003 of 2023 - Urban Forest Action Plan03
Passed by the City Council of Salt Lake City, Utah, this ___ day of _____ _
2023.
CHAIRPERSON
ATTEST AND COUNTERSIGN:
CITY RECORDER
Transmitted to Mayor on __________ _
Mayor's Action: ___ Approved. Vetoed. ---
CITY RECORDER
(SEAL)
Bill No. of 2023. ----Published: -------Ordinance adopting the Urban Forest Action Plan MAYOR
APPROVED AS TO FORM Salt Lake City Attorney's Office Date: -------
B:� Katherine D. Pasker, Senior City Attorney
21st February
03
Mar 7, 2023
Apr 14, 2023
Erin Mendenhall (Apr 21, 2023 14:40 MDT)
4
April 26, 2023
Ordinance 03 of 2023 Urban Forest Action Plan
Final Audit Report 2023-04-26
Created:2023-03-03
By:Thais Stewart (thais.stewart@slcgov.com)
Status:Signed
Transaction ID:CBJCHBCAABAAyoqKEoohBZCF9uK_eCChJpd244Ye06Fy
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URBAN FOREST ACTION PLAN
SALT LAKE CITY
DEPARTMENT OF COMMUNITY & NEIGHBORHOODS // PREPARED BY THE PLANNING DIVISION // ADOPTED FEB 2023 // V.1
[ PAGE LEFT BLANK INTENTIONALLY ]
DEPARTMENT OF COMMUNITY & NEIGHBORHOODS // PREPARED BY THE PLANNING DIVISION // ADOPTED FEB 2023 // V.1DEPARTMENT OF COMMUNITY & NEIGHBORHOODS // PREPARED BY THE PLANNING DIVISION // ADOPTED FEB 2023 // V.1
URBAN FOREST ACTION PLAN
SALT LAKE CITY
INTRODUCTION
SALT LAKE CITY URBAN
FOREST ANALYSIS: STRENGTHS,
VULNERABILITIES, OPPORTUNITIES,
+ CONSTRAINTS
LIVABILITY + THE URBAN FOREST
IN SALT LAKE CITY
BEST MANAGEMENT PRACTICES
FOR A THRIVING URBAN FOREST
Contents
no. 1
no. 2
no. 3
no. 4
no. 5
GROWING AN EQUITABLE
URBAN FOREST IN SALT LAKE CITY
84 The Urban Forest is Public Infrastructure
90 Maximize the Urban Forest’s Return on Investment (ROI)
98 Partner to Equitably Distribute Urban Forest Benefits
101 Plan and Design the Urban Forest in the Public Interest
9 Urban Forest Contributions
10 Environmental Benefits
11 Community Benefits
12 Salt Lake City’s Urban Forest
13 Urban Forest Action Plan Purpose
17 Strengths
22 Vulnerabilities
28 Opportunities
32 Constraints
34 Equity
42 Salt Lake City Census Tract Analysis
44 Environment
45 Ordinance
49 Urban Design
60 Policy
65 Preservation
69 Promotion
73 Placemaking
6
What does the urban forest look like in your neighborhood? Is it full and thriving,
its shade expansive and cooling? Or is it weak and declining, too sparse to improve
air and water quality? Do trees shade the west side of your home or workplace,
conserving energy and sequestering carbon?
Municipalities across the United States have increasingly come to recognize the value
that the urban forest provides to environmental, economic, and community health.
Urban forests deliver a vast range of benefits to our cities, from improved air and water
quality and school performance, to reduced urban heat impacts and childhood asthma
rates. We now know that healthy urban forests are dynamic contributors to flourishing
communities. While we often refer to parks as the “lungs of the city,” it is the urban forest
that often fills that role.
More recently, municipalities have begun to reckon with biases in the way cities are
planned and built and to consider how these inequities extend to the urban forest.
Multiple recent studies demonstrate that areas considered “prime real estate” in the 1930s
have two to four times more tree canopy than formerly redlined areas. Nearly a century
later, this disparity matters because it correlates to continued adverse public health
outcomes, reduced livability, and decreased resilience in the face of climate change.
EXECUTIVE SUMMARY
STRATEGIES FOR A THRIVING URBAN FOREST
The strategies presented in this action plan provide guidance for Salt Lake City to align its
resources and actions in the built environment with its goals for sustainability and equity
and describes concrete steps to implement equitable practices for a resilient future.
7
THE URBAN FOREST IS PUBLIC INFRASTRUCTURE
When properly planned, planted, and protected, urban forests contribute to public and
environmental health and mitigate some effects of climate change. Salt Lake City should
strive for balance in stewardship of its urban forest, which can be achieved by viewing
the urban forest as public, living infrastructure. As cities grow and change, trade-offs
must occur to increase housing, transportation, and employment choice for residents.
Well-managed infrastructure systems make our cities healthy, livable places, and require
funding to build and maintain. By valuing the urban forest as public infrastructure with
wide-ranging benefits, the City can make better, more informed decisions about the urban
forest’s growth and preservation.
MAXIMIZE THE URBAN FOREST’S RETURN ON INVESTMENT
The living infrastructure of Salt Lake City’s urban forest provides economic,
environmental, and community returns much greater than any single built infrastructure
system. To responsibly steward taxpayer dollars, the City’s policy and planning decisions
guiding the City’s investments in the preservation and growth of the urban forest should
maximize these returns. Enhanced coordination between City departments and partners,
and new approaches to infrastructure that combine functions, can help Salt Lake City
reap the greatest returns on all the benefits the urban forest provides. From carbon
sequestration to improved community cohesion, the urban forest can both mitigate
negative environmental impacts and provide positive returns to public health.
PARTNER TO EQUITABLY DISTRIBUTE URBAN FOREST BENEFITS
To implement the growth and maintenance of the urban forest at the scale needed to
mitigate environmental and public health impacts, the City should explore partnerships
with a range of organizations and agencies. At the same time, revisiting and redefining
the equitable rights and responsibilities of residents in stewarding neighborhood street
trees is critical to ensuring the City will continue to benefit from the urban forest over the
long term. Investigating and implementing new and expanded mechanisms for funding the
urban forest will also increase the equitable distribution of its benefits.
PLAN AND DESIGN THE URBAN FOREST IN THE PUBLIC INTEREST
Planning for the urban forest with an approach that combines urban design principles
for creating inviting, attractive, and comfortable places for people with environmental
impact mitigation strategies is key to public health and wellbeing returns. As the City
grows, planning and designing the urban forest to enhance its environmental and
aesthetic benefits in our public spaces (sidewalks, streets parks, and plazas) will become
increasingly critical to maintaining livability.
This Action Plan offers a full range of strategies to help planners, designers, and
land managers continue to rethink and reinvigorate the performance of Salt Lake
City’s urban forest. This plan charts a course to preserve and grow the capacity of
our living infrastructure to clean our air, cool our City, and create great community
places for all Salt Lakers.
8
9
An increase in canopy coverage, appropriate tree selection, and emphasis on the
importance of tree care can support a wide range of Salt Lake City’s economic,
environmental, public health, planning, community cohesion, and urban design goals,
including improvements to:
Introduction
Urban forests are vital contributors to thriving cities. When properly planned, planted,
and protected, urban forests promote both public and environmental health and can
mitigate some effects of climate change. Our urban forest is an asset that Salt Lake City
residents treasure. In the City’s 25-year general plan, Plan Salt Lake (2015), residents
named the urban forest as one of our greatest assets and called for its continued
preservation and expansion.
Urban forests are composed of all trees, including those in riparian and wetland areas,
within a city. Unlike their natural area counterparts, urban forests regularly interact with
all aspects of city life, including pavement, pollutants, auto emissions, salt and sand,
urban heat island, construction impacts, and above and underground utilities, among
others. A growing, thriving urban forest is only possible with a careful combination of
planning, policy, and design. That combination must balance the imperative of water
conservation with a comprehensive, equity-based approach to the role of trees in the
watershed and air quality. At the same time, City policies should account for the full
range of benefits and costs of urban forests.
Salt Lake City’s history as an urban place is closely tied to the history of its urban forest.
When emigrants arrived in the Salt Lake Valley in 1847, their first concern was water. The
second was shade. Settlers quickly planted vines to grow shade over their first, simple
earthen homes. Then they planted and cultivated trees to transform the first streets and
canals of the Plat of Zion into a livable city. By caring for our urban forest, we continue a
positive legacy of those city-makers and embrace our urban heritage.
n
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1
• Air Quality
• Water Quality
• Energy Conservation
• Carbon Sequestration
• Urban Heat Island Effect Mitigation
• Retail Sales
• Employee Satisfaction
• Public Health
• Mental Health
• School Performance
• Environmental Equity
• Transportation
• Urban Design
• Community Cohesion
Urban Forest Contributions
These improvements are briefly summarized below. Except where noted, this information
was gathered from the Vibrant Cities Lab, a joint project of the US Forest Service,
American Forests, and the National Association of Regional Councils. The Vibrant Cities
Lab website has detailed information, research, and supporting data.
10
Environmental
Benefits
WATER QUALITY
Urban forests slow stormwater flows and reduce peak discharge
during storms by holding water in the canopy and root system,
allowing stormwater to slowly infiltrate into the ground. Slowed
stormwater contributes to a healthier hydrologic system and aquatic
ecology, because stormwater in pipes flows quickly which raises
the water temperature and can negatively impact life downstream.
Trees also filter pollutants from water, including nitrogen and
phosphorus (typically found in fertilizer and pet waste).
AIR QUALITY
Trees reduce air pollution through the uptake of ozone, carbon
dioxide, nitrogen dioxide, sulfur dioxide, and particulate matter
less than 2.5 microns wide (PM2.5). Strategically locating tree
plantings can reduce the impacts of air pollution. For example,
vegetation barriers along roadways encourage the mixing of air
strata and can reduce ground-level pollution.
ENERGY CONSERVATION
Trees reduce the energy consumption of commercial and
residential buildings. According to the Lawrence Berkeley
Lab Heat Island Group, “each one-degree F increase in peak
summertime temperature leads to an increase in peak demand
of 225 megawatts,” resulting in $100 million in annual costs to
customers. (Center for Neighborhood Technology, 2010).
CARBON SEQUESTRATION
According to the U.S. Geologic Survey, carbon sequestration is
the “process of capturing and storing atmospheric carbon dioxide.
It is one method of reducing the amount of carbon dioxide in the
atmosphere with the goal of reducing global climate change.”
(USGS, 2021) Trees sequester and store carbon dioxide (CO2);
adding trees in cities (in combination with other strategies) can
reduce the amount of atmospheric CO2.
URBAN HEAT ISLAND EFFECT MITIGATION
Shade trees mitigate urban heat island effects created by
impervious, paved surfaces. The shade and transpiration (the
process by which tree leaves give off water) properties of
trees can reduce peak summer temperatures between 2 – 9
degrees Fahrenheit.
ECONOMIC BENEFITS
Tree-lined streets are correlated with increased retail sales,
customers remaining in business districts longer, and patron
visitation from further away (Wolf, 2009). Studies have also
demonstrated that trees and plants boost employee productivity
and job satisfaction. Trees and plants also have a well-known
positive impact on property values.
11
URBAN HEAT ISLAND HEALTH IMPACTS
Community Benefits
PUBLIC HEALTH
Numerous studies demonstrate the connection between the
ability to experience nature and improved mental and physical
health. Urban forests reduce the incidence of respiratory disease,
cardiovascular disease, heat-related illness, and skin cancer.
Walking through areas with trees and other vegetation and even
viewing vegetated areas through windows has been demonstrated
to reduce anxiety, stress, depression, and aggression. Studies of
trees and vegetated spaces in cities also showed improved school
performance and reduced ADHD symptoms.
Cities generally have a significant amount of paved or built surfaces with a low solar reflectance (albedo), such as asphalt, leading
to higher temperatures. Urban spatial organization, urban form, lack of vegetation, and waste heat also contribute significantly to
the heat island effect. A 2015 University of Georgia study found that the Salt Lake City metro area ranked among the top 4 of
50 U.S. metropolitan areas for intensity of urban heat island (UHI) effect.
Salt Lake City’s UHI creates several public health impacts. Heat, especially days over 90° F, is the primary driver of weather-
related deaths in the United States (Climate Central, 3). Higher summer temperatures increase concentrations of ground-level
ozone, contributing to air pollution. Higher temperatures and air pollution increase the incidence of respiratory diseases, heat
exhaustion, heat stroke, and heat-related mortality.
Ozone pollution causes a range of respiratory problems. Sensitive groups, such as children, older adults, and people with
health conditions are at higher risk during heat waves, which are exacerbated by UHI effects. The Center for Disease Control
and Prevention estimates that during the 24-year period from 1979-2003, “excessive heat exposure contributed to more than
8,000 premature deaths in the United States. This figure exceeds the number of mortalities resulting from [all natural disasters]
combined.” (https://www.epa.gov/heat-islands/heat-island-impacts, accessed July 2019)
URBAN DESIGN
Street trees and urban forests also make vital contributions to
the urban design identity of neighborhoods and districts. In Salt
Lake City, we can implement urban forest design to increase
the number and quality of human-scale spaces in our oversized
streetscapes. By creating inviting, pedestrian-scaled places in
the city using street trees to mediate between the width of our
streets and the height of our buildings, we can make places that
encourage positive interactions between residents.
12
As Salt Lake City undergoes record growth and development
during the era of climate change, our urban forest faces new
threats. When we add more paving to our city, without planning
for adequate environmental and social mitigation, livability
decreases. As the city heats up and air and water quality
decline, our sidewalks and public spaces become unpleasant
places that we avoid. Avoiding these places will deprive us of
the city’s most critical purpose: the ability to interact with our
fellow residents and visitors.
Salt Lake City’s Urban Forest Action Plan aims to:
• Assess existing policies, plans, and practices,
• Gather best practices and solutions,
• Provide strategic, prioritized recommendations to preserve and grow our urban forest equitably.
The Urban Forest Action Plan will contribute to Salt Lake City’s
resilience ecologically, economically, and socially by increasing
the number, health, growing conditions, and longevity of trees in
the urban landscape.
Salt Lake City’s
Urban Forest
ENVIRONMENTAL EQUITY
Numerous studies have shown that lower-income, historically
marginalized groups, and renters tend to live in urban areas
with the fewest street trees in public rights of way. Careful
planning of the urban forest is needed to ensure an equitable
distribution of its benefits.
TRANSPORTATION
The appropriate use of trees in streetscape design results in
traffic calming, reduced collision risk, and an inviting environment
for walking and biking, promoting active transportation and
recreation activities.
COMMUNITY COHESION
Trees enhance neighborhoods by creating inviting gathering places
and providing more opportunities for neighbors to socialize and
build community. Studies demonstrate an association between the
number of trees and community cohesion in urban neighborhoods.
Most of the trees in Salt Lake City were planted by hand.
13
Urban Forest Action Plan Purpose
Salt Lake City’s urban forest is critical to our quality of life but is currently an underutilized and
an undervalued asset (see chapter 2 and chapter 3 for details). An action plan will address
and prioritize the urban forest’s multiple opportunities and challenges and engage a full range of
agency, institutional, private, and community stakeholders.
Action plans address interconnected challenges, develop priorities, find solutions, and build
a long-term plan of action. Policymakers, planners, and community members create and
implement action plans to unite a broad range of stakeholders around a shared cause.
These stakeholders include community members, non-profit organizations, private interests,
institutions, and governmental agencies. As subsequent chapters detail, the expansion of the
urban forest can play an important part in addressing many of the interconnected challenges
that Salt Lake City faces. However, it will take a joint government, institutional, private sector, and
community effort to grow and maintain our urban forest.
Challenging growing conditions in cities (from compacted soils to numerous utilities) call for careful planning and design of the urban forest.
14
Unshaded asphalt and concrete on Salt Lake City’s roadways and sidewalks exacerbate high temperatures in the summer.
15
Salt lake City
Urban Forest
Analysis:
Strengths, Vulnerabilities,
Opportunities, + Constraints
Salt Lake City’s urban forest is critical to our quality of life. However, it is currently an
undervalued and underused asset. In the past decade, Salt Lake City’s record growth
has impacted the urban forest. Development has contributed new trees to our streets
and private lands. Yet, we have also lost established trees due to tree removal or root
damage incurred in the process of accommodating growth.
New construction, changes in technology, and the need to provide services to more
residents have increased competition to locate utilities within the park strip. Despite
available solutions, these utilities often assume the space required for trees to thrive.
This chapter assesses Salt Lake City’s urban forest’s current strengths,
vulnerabilities, opportunities, and constraints. This analysis creates a baseline for
comparison to evaluate the effectiveness of the Urban Forest Action Plan’s future
implementation strategies.n
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2
16
The rate at which Salt Lake City loses public trees doubled
every decade between 2008 and 2018. The hurricane-force
windstorm in September 2020 decimated over 1,500 public trees,
including many older specimens. Between the Mayor’s 1,000 trees
initiative and Urban Forestry’s scheduled planting, Salt Lake City
planted more than 2,000 new trees in 2020.
However, replacements for mature, large trees take decades
to provide comparable air and water quality mitigation capacity.
With continued development and climate change, adverse
environmental impacts will increase. At the same time, declines
in the City’s urban forest impair its ability to mitigate these impacts.
The urban forest has numerous strengths, including existing tree
stands, code and policy provisions, public support, and public
appreciation for its many benefits. Building upon these strengths
can address the vulnerabilities that occur primarily due to a
fragmented approach to planning and managing the urban forest.
The urban forest is a living infrastructure system that requires
sustained interdepartmental collaboration to optimize its benefits.
The urban forest also needs land managers to implement
solutions when conflicts occur between infrastructure systems.
The handful of constraints on the City’s urban forest, while
significant, can be addressed through careful planning
and mitigation measures and strategic investment in
irrigation infrastructure.
The City’s existing urban forest cannot effectively meet climate
change challenges and growth opportunities without significant,
strategic intervention, paired with ongoing planning for the future.
While other means of mitigating environmental impacts are
available, most are more expensive than tree planting. And
few (if any) of these mitigation measures provide the multiple
ecological, social, and urban design benefits that trees do. By
prioritizing the many opportunities available to preserve and
grow the urban forest, Salt Lake City can build resilience into its
urban fabric while fostering healthy communities.
Liberty Park is Salt Lake City’s most visited park, and over one-third of visitors describe the trees as their paramount reason for visiting.
17
This plan defines strengths as factors that support the goal of
growing and preserving the urban forest. These factors include
existing assets, ordinances, policies, skill sets, or other municipal
or resident practices.
Strengths
EXISTING URBAN FOREST
When considering the City’s urban forest, it is valuable to note
that people intentionally planted nearly all trees throughout Salt
Lake City (except those along waterways).
Salt Lake City’s publicly owned urban forest comprises roughly
86,500 individual trees; approximately 75% of these are
street trees in the right-of-way (ROW). The remaining 21,000
grow in City parks and other public lands.
According to a 2019 analysis, these trees create 1,455 acres of
canopy cover, or just over 2% of Salt Lake City’s total land area of
111.1 square miles (SLC Urban Forest Resource Analysis).
Geographic Information System (GIS) analysis from 2014 EPA
Meter Scale Urban Land data that includes private lands
expands the City’s canopy coverage to 15% of the City’s land
area (10,778 acres).
PUBLIC APPRECIATION OF TREES
One of Salt Lake City’s urban forest’s greatest strengths is the
community’s high regard for it. The value residents place on the
urban forest has been demonstrated through public engagement
(see appendix for detail) and current tree care practices.
Plan Salt Lake, adopted in 2015, demonstrates the appreciation
residents have for the urban forest, noting: “Salt Lake City
residents and visitors recognize our green network, including
our urban forest, parks, and street trees, as one of our
greatest assets” (31).
The Salt Lake City Urban Forestry Division receives between
4,000 and 5,000 requests for service annually. New tree
planting requests have also increased in recent years,
demonstrating residents’ expanding interest in the urban forest.
Salt Lake City requires residents to water street trees. The
significant number of thriving trees demonstrate that many
residents are willing and able to support the urban forest with
time and money.
18
The Salt Lake City Streets and Intersection Typologies
(ongoing) will assist the City in creating place-based streets
that work for all users. The guide proposes new classifications
and prototypes for a range of Salt Lake City street types. The
typologies consider land use, City, and neighborhood goals and
allocate the public right-of-way to prioritize people.
Street trees play a significant role in the design guide. The guide
acknowledges the urban forest’s considerable environmental,
transportation safety, retail district improvement, and community
functions in making streets attractive, accessible, and equitable
places for people.
The Salt Lake City Street Lighting Master Plan (2020) expands
upon the Transportation Division’s 2006 policy of coordinating
new streetlight locations with new trees. The plan recommends
using pedestrian lighting in addition to street lights in areas
where street trees create shadows to support a safer and more
visually comfortable environment (45).
SALT LAKE CITY PLANS
Plan Salt Lake includes initiatives for incorporating trees in
City rights-of-way in nearly one-third of its guiding principles:
Neighborhoods, Transportation and Mobility, Air Quality, and
Beautiful City.
The Transportation Division’s current plans also highlight the
need for trees to implement successful, well-used transit routes.
These plans also call for more shade trees to create comfortable,
beautiful pathways for walking and other active transportation.
The Salt Lake City Transit Master Plan recommends investing
in street trees on Frequent Transit Networks as a near-term, high
priority strategy related to placemaking and design (SLC Transit
Master Plan, 6-8, 2017).
The Salt Lake City Bike and Pedestrian Master Plan (2015)
notes that street trees have a “profound effect” on improving
street corridors for pedestrians. The plan recommends that
the City include street trees, particularly shade trees, in its
streetscape designs (43). Additionally, it notes that trees create
an important functional and aesthetic buffer between the
sidewalk and the roadway (57).
Several Salt Lake City Community Plans also note the
importance of street trees, notably the Downtown Plan
(2016), which emphasizes their importance in establishing
district design identity:
Trees…contribute to the image and identity of districts.
Street trees strengthen the image of Downtown,
contribute to the character of individual districts, provide
comfort and amenity to public spaces, and perform
essential ecological services that make a healthy urban
environment. …Street trees that provide a regular,
continuous canopy reinforce the formal symmetry,
regularity and “grand” landscape-scale of Downtown’s
main streets. (21)
On streetscapes with trees, lighting vehicle and pedestrian pathways at night enhances safety and visual comfort for pedestrians.
19
• Energy Savings ($1 million): The urban forest reduces
energy consumption for heating and cooling in multiple
ways. The urban forest:
• Provides shade, reducing both surface and ambient
temperatures on concrete, asphalt, and other paving
materials (heat island effect);
• Transpires (releases water vapor), cooling the
surrounding air;
• Provides passive solar heating, allowing sunlight to reach
interior spaces in winter after deciduous leaves fall;
• Reduces wind speeds and the movement of wind into
buildings; and
• Reduces heat loss on surfaces with high thermal
conductivity (21-32).
Salt Lake City’s Urban Forest currently provides a range of
air quality, stormwater management, aesthetic, urban design,
cooling, and energy-use reduction benefits to the City, along
with public health benefits, both physical and mental. While
some of the urban forest’s benefits can be quantified, others are
qualitative and have a significant impact on Salt Lake City’s goals
for livability, emissions reduction, and placemaking.
QUANTITATIVE BENEFITS
Davey Resources Group extensively detailed and quantified
many specific benefits of trees on Salt Lake City property in
the 2019 Salt Lake City Urban Forest Resource Analysis. (See
Appendix A for details).
The analysis found that the total estimated benefits
provided by Salt Lake City’s public trees are worth nearly
$7.5 million annually.
ENVIRONMENT
Salt Lake City’s public trees currently provide $1.7 million in
environmental services annually:
• Improved air quality ($140K): Trees absorb pollutants
(ozone, sulfur dioxide, nitrogen dioxide) through leaf
surfaces, intercept particulate matter (dust and smoke),
produce oxygen via photosynthesis, and provide cooling,
which reduces ozone formation.
• Stormwater management ($330K): Leaves and root masses
work to intercept rainfall, which decreases the amount of
stormwater flowing into storm drains. Trees also increase
soil infiltration capacity, recharging groundwater supplies,
reducing stormwater volumes, and improving water quality
through pollutant uptake. Soil infiltration provides ecological
benefits by filtering water before it enters rivers and streams
and economic benefits to the City by reducing the need to
invest in gray stormwater infrastructure.
• Carbon Reduction ($92K): Trees accomplish this directly
via carbon uptake in leaves and biomass. They indirectly
reduce carbon by providing shade and passive solar
benefits, reducing emissions associated with building
energy consumption.
ECONOMY
Property values and commercial rental rates increase as trees
mature and canopies become large. The Salt Lake City Urban
Forestry Division compared neighborhoods with many trees to
those with few or none. The analysis estimated that public
trees provide a range of socio-economic benefits equaling
nearly $6 million annually. (33)
A national survey of business districts found healthy urban
forests correlate with increased retail sales and spending and
customers remaining in business districts longer. In addition,
patrons are willing to travel longer distances and spend
approximately 10% more in business districts with trees. (Wolf,
2009). Salt Lake City’s Economic Development department
considers the 9th and 9th neighborhood the “showcase” retail
district. It has many mature trees both within the right-of-way and
on adjacent private property.
RETURN ON INVESTMENT (ROI)
The City invests $2.2 million annually in the urban forest by
planting, pruning, irrigation, administration, and other infrastructure
management. According to the 2019 assessment, the total annual
benefit (environmental and socio-economic) that the urban forest
provides is $7.5 million, for a net yearly gain of $5.3 million.
Put simply, for every $1 Salt Lake City invest directly
in the urban forest, it receives $3.40 in benefits (38).
20
Urban residents in early Salt Lake City understood that trees were fundamental to a livable city. (Utah State Historical Society, circa 1877-1880)
CULTURAL VALUES
Salt Lake City’s history as an urban place is closely tied to its
urban forest. When emigrants arrived in the Salt Lake Valley in
1847, their first concern was water. The second was shade for
thermal comfort. Settlers first planted vines to grow shade over
their early, simple earthen homes quickly. They just as promptly
planted and cultivated trees to transform the streets and canals
of the Plat of Zion into a livable city.
There are notable trees with cultural value throughout Salt Lake
City. The locust tree planted near the Beehive House in Temple
Square (at the State Street entrance). Harriet Page Wheeler
Decker, mother-in-law to Brigham Young, arrived with the first
pioneer company in the Salt Lake Valley on July 24, 1847. She
carried a locust tree seed on the Mormon Pioneer Trail and
planted it near the Beehive House kitchen door. Reputed to be
the first residential landscape tree in the Valley, photographs
show that a locust tree has remained in that location since the
1850s, even withstanding the impacts of an addition to the
house in 1889.
Even tree locations have cultural importance to Utahns. On
600 East, just south of the intersection with 300 South, a
center median contains a monument to “The Lone Cedar Tree,”
erected by the Daughters of the Utah Pioneers (DUP) in 1960.
The Lone Cedar may have been a landmark in grasslands that
characterized the mid-nineteenth century Salt Lake Valley. In the
immense vistas of the western United States, landmarks were
critical navigation tools used during the overland migration.
QUALITATIVE BENEFITS The DUP resolved to memorialize the Lone Cedar Tree after it
was “thoughtlessly” cut down (as the plaque notes). Their efforts
demonstrate its cultural and historical reputation to residents
more than a century after Salt Lake City’s founding.
Mayor Erin Mendenhall created a campaign to plant 1,000 trees
on Salt Lake City’s West Side in 2020 and secured private
funding for this effort. The planting kick-off was held on Arbor
Day in April 2020, even while the administration addressed the
combined emergencies of the global COVID-19 pandemic and a
magnitude 5.7 earthquake a month prior. After a hurricane-force
windstorm in September 2020, the Mayor worked with non-profit
and private sector partners to replant the nearly 2,000 trees lost
on City-owned land. (See September 2020 Windstorm below).
RECREATION + ACTIVE TRANSPORTATION
Trees play a critical role in recreation and active transportation
activities in Salt Lake City. For example, the 2019 Salt Lake City
Parks and Public Lands Needs Assessment surveyed residents
and visitors to parks. The Assessment found that Liberty Park
is the most visited park in the City, and one-third of survey
respondents noted that their primary reason for visiting Liberty
Park is the trees (xiii).
The Salt Lake City Bikeways Map recommends selecting routes
based in part on street trees and available shade. This guidance
demonstrates trees’ importance in providing comfort and shade
when making active transportation choices.
21
TREE AGE DISTRIBUTION IN
THE URBAN FOREST
Age distribution is critical in the urban forest because single-
age tree stands are more likely to die simultaneously. Arborists
typically describe a tree’s age using its size, or DBH (diameter
at breast height). DBH is the standard method used to
describe the width a tree trunk at 4.5 feet above the ground.
By ensuring trees have a range of DBH, managers can plan for
urban forest succession. Planning ensures that new trees have
sufficient time to establish to replace mature trees with more
extensive canopies.
The current age distribution of Salt Lake City’s public trees is
nearly optimal from a resource management perspective. 41%
of trees are eight inches or less DBH, while 12% are larger than
twenty-four inches DBH. This age distribution generally allows
Urban Forest managers to anticipate annual maintenance costs
and plan the expenditure rate from year to year.
SALT LAKE CITY CODE
The Salt Lake City Urban Forestry Ordinance (Chapter 2.26.210
of the Salt Lake City Code) requires a permit to plant, maintain,
or remove trees on public land. It also requires replacements or
remuneration for any tree removed. (Removal fees, however, do
not capture the value of ecosystem services trees provide).
The zoning code contains provisions to protect some trees on
private land (21A.48.135), namely healthy, viable “specimen trees.”
Specimen trees are defined as either single trees or tree groups
that measure at least 10” in DBH (see Tree Age Distribution,
above) or more. The code states, “specimen trees shall be
preserved to the maximum extent practicable as determined by
the city forester, in consultation with the zoning administrator.”
However, there are some instances where developers can
provide cash instead of replacement trees. Salt Lake City Code
also preserves and protects urban forests on specific parcels of
private land through the Planned Development process detailed
in 21A.55.010.A.
Some zoning districts and overlays protect natural lands and
riparian corridors that the City could amend to include provisions
to preserve trees. Namely, the Natural Open Space District,
Open Space District, Foothills Protection District, Riparian
Corridor Overlay, and the Lowland Conservancy Overlay. That
said, currently, the text does not mention protections for forest
stands or individual trees specifically.
CITY POLICIES
In January 2020, Mayor Erin Mendenhall updated City policy to
incorporate sustainability into operational decision-making. She
requested all department directors to submit memoranda detailing
how their operations could mitigate adverse environmental
impacts or improve environmental quality.
PRIORITIZING TREES IN PARK STRIPS
A car-dominated city, Salt Lake allowed paved parking spaces or
driveways to occupy prime spots for trees in the public right-of-
way for decades. Before 2020, the City regularly granted permits
to remove trees to make space for cut-in parking stalls within
park strips or to create driveways to existing homes.
At the same time, new parking stalls induce demand for driving,
thereby increasing emissions. In 2020, the Community and
Neighborhoods Department led an effort supported by other
City Departmental stakeholders to address the inconsistency
between the environmental impacts of parking policy and the
City’s commitment to air and water quality. The consensus
recommendation was to create a new Salt Lake City policy to
eliminate the practice of replacing park strips with parking or any
other impervious surface, with rare exceptions.
22
The goal of the Urban Forest Action Plan is to develop
strategies to preserve and grow the Urban Forest; this plan
defines vulnerability in Salt Lake City’s Urban Forest as:
• Unresolved conflicts,
• Gaps (in ordinance, policy, guidance, enforcement, or
other City practices), or
• Loss or absence of skill,
That undermines the goal of growing and preserving the
urban forest.
Chapter 4 of this plan examines best practices in other
cities that address these vulnerabilities, and chapter 5
recommends actions to address and correct vulnerabilities
and prioritize solutions.
Vulnerabilities
ACCELERATING RATE OF TREE LOSS
The rate at which Salt Lake City is losing urban forest trees has
doubled every decade over the past twenty years. Salt Lake City
removed 300 trees in 1998, 600 trees in 2008, and 1200 trees in
2018. Salt Lake is not unique in its loss of trees. A recent Nature
Conservancy study looked at 27 US cities and found that 85% had
declines in canopy cover between 2004-2014. (Kroeger, 2018)
While the City has replaced many of these trees, replacement
plantings for a single large tree will take 75 to 100 years to
provide enough canopy to mitigate air and water quality impacts
and heavy stormwater flows (PAS, 2014). Additionally, many of
the City’s fastest-developing areas, such as Downtown, are also
those that are already the most heavily paved. Thus, tree loss in
these locations exacerbates the urban heat island (UHI) effect
and localized flooding.
LACK OF COMPREHENSIVE
PLANNING FOR THE URBAN FOREST
Salt Lake City lacks an urban forest master or management plan,
which would provide comprehensive, prioritized guidance to
equitably deliver the benefits trees provide. A master plan focused
on the urban forest could address maintenance, management,
long-term funding, staffing, disaster response, and mitigation,
and provide robust strategies and best management practices to
maximize the urban forest’s return on investment (ROI).
URBAN FOREST ORDINANCE +
POLICY CONFLICTS
Over the past decade, the City has developed at a rapid
pace. The pace and scale of development has sometimes
left City policies and practices unable to meet current
needs. The City has, at times, found itself unable to strike an
effective compromise between urban forest preservation and
development activity.
Existing policies related to land use in the right-of-way (ROW)
sometimes conflict with City policies for the urban forest and
make it difficult to plant trees in many areas. For example, Public
Utilities Department policy directs trees to be planted at least
10 feet away from water and sewer lines. A recent analysis of
tree planting spots in the ROW found that approximately 24,000
suitable locations exist (Davey Resource Group, 2019). When this
spatial analysis was paired locations of water and sewer lines
using GIS, however, the number of planting locations dropped
by more than half -- to 10,000 viable tree sites in the ROW.
When sustainability criteria (energy use reduction) are applied to
potential tree locations, however, that number drops to less than
200, or 0.8% of the total number of planting locations identified.
While products exist that can direct tree root growth away from
pipes, they add additional costs to project budgets. Currently,
these are not a line item in either Public Utilities or Urban
Forestry’s budgets.
Private property owners whose land abuts park strips are
responsible for watering and fertilizing trees and protecting them
from damage caused by lawnmowers and similar equipment
(Section 2.26.190). Yet, Salt Lake City has no mechanism to
enforce this policy. The City would need additional revenue
streams to enforce this policy equitably, or the cost burden
would be more significant on lower-income owners. Additionally,
this policy assumes that residents know their responsibilities and
have adequate information and experience with tree irrigation,
which is not always the case.
Existing city code has conflicting regulations for street trees. If
an adjacent property owner challenged the City, it would have
limited ability to maintain its public infrastructure. For example,
the Urban Forestry chapter (2.26.210) states, “The urban
forester must approve any permit for removal of public trees.”
Permit approval is conditioned on the provision of replacement
trees or compensation.
23
Yet the regulations for existing street trees in the Landscaping
and Buffers chapter (21A.48.050) state, “the removal of trees
within the street right of way is prohibited without the approval
of the zoning administrator in consultation with the urban
forester.” Without reconciliation, these inconsistencies leave the
City open to challenge by property owners who do not accept
trees as a public benefit.
Additionally, the City has yet to establish clear, definitive
thresholds for conserving the urban forest. Without clear
conservation guidance, it is more challenging to preserve and
maintain the collective benefit they provide. The code typically
regulates individual trees rather than the entire urban forest as a
modified natural system.
INADEQUATE TREE REMOVAL
MITIGATION POLICY
Currently, Salt Lake City’s tree replacement policy does not
account for a tree’s total ecosystem value. City ordinance
requires replacements for trees removed for construction or
that the cash value of the timber is paid into a revenue account
to plant and preserve the urban forest. Therefore, the City does
not receive the full benefit when cash or replacement trees are
provided for removed trees.
Small trees (2-inch caliper) are the best to establish in Salt Lake
City’s difficult growing conditions. Bigger trees are generally
more costly and prone to early mortality when transplanted.
Therefore, if a large tree is removed, the “in-kind” replacement is
made with an equal number of 2-inch caliper trees. For example,
a 20-inch caliper tree replacement consists of ten 2-inch caliper
trees. However, ten young trees can take decades to provide
similar ecosystem services as a single mature tree. Given the
challenges and stresses of urban growing conditions and climate
change, new trees may never offer the same ecosystem services
as those they replaced.
While Salt Lake City’s urban forest’s age distribution is
generally healthy, 56% of trees in Salt Lake City are on the
younger end of the spectrum. These young trees require
adequate care and water to ensure they reach maturity and
provide maximum benefits.
With the growth and construction rate Salt Lake City has
undergone in the past decade and climate change impacts,
the urban forest is becoming younger. As a result, the urban
forest is less equipped to mitigate the environmental impacts
of rapid development and increased emissions related to
population growth.
NEED FOR MORE PLAN
REVIEW CAPACITY
There is inconsistent attention to tree roots’ size and location in
site plan review, notably in demolition and construction staging
plans. Plan reviewers outside the Urban Forestry division are
not trained to assess conditions for tree growth and survival.
Evaluation and correction by a qualified reviewer during these
initial stages are critical to ensure that trees need not die
unnecessarily. Furthermore, Urban Forestry has limited resources
to allocate to plan review, presenting real challenges to tree
preservation given the expanding pace of development in Salt
Lake City.
City ordinance (21A.48.050) prohibits “the removal of trees within
the street right of way … without the approval of the zoning
administrator in consultation with the urban forester.” Yet, in most
cases, when tree removal is requested, the application does not
come before the zoning administrator for consideration, breaking
a vital link between Planning and Urban Forestry.
UTILITY + URBAN FOREST CONFLICTS
Conflicts between overhead and underground utilities and trees
have become increasingly frequent during the City current
period of rapid development. While many utilities are located
underneath the roadway, the City permits others to be installed
the park strip, where they compete for space with tree roots.
Trees are regularly removed or damaged to accommodate
underground utilities in the park strip.
The most significant tree and utility conflicts in the Salt Lake
City area are between root systems and water and sewer
lines and between tree canopies and above-ground electricity
infrastructure. These conflicts occur frequently and lead to
tree removal and damage, unaesthetic pruning, and loss of
(otherwise viable) tree planting sites.
Overhead utility lines often prevent appropriately scaled trees
from being planted along Salt Lake City’s wide streets. Electric
transmission lines are costly to bury and are typically only cost-
effective to place underground when there is at least a mile-
long section. Typical development on a single parcel is a much
smaller scale. Currently, transmission lines prevent the City from
planting trees that can adequately shade our large rights-of-way.
24
INADEQUATE SOIL VOLUMES
Areas that are most heavily paved, such as Downtown streets,
require more shade to offset the increase in pavement surface
and ambient temperatures. The same is true of bus shelters built
on concrete pads. However, standard paving practices reduce
the amount of available soil required to provide sufficient root
space for large shade trees. Salt Lake City has made advances
by introducing structural soils under the pavement in some areas.
However, soil cell (or suspended pavement) systems are generally
preferable. They tend to produce sizable, healthier trees while
also managing stormwater. (See Chapter 4, Suspended Pavement
Systems, for additional details).
NEED FOR MORE SUSTAINABLE
APPROACHES TO FIRE ACCESS
Both life safety and sustainability are the foremost priorities in
Salt Lake City. Still, the City has yet to fully explore the wide
range of solutions to create a both/and approach to fire access
requirements and sustainability.
Requirements for unobstructed area for fire apparatus (ladders,
etc) access have led to developers removing large trees and soil,
and the introduction of more pavement into the right-of-way (ROW).
The Department of Community and Neighborhoods and the Fire
Department worked closely to find a range of alternative means
of fire prevention. However, these are optional to the developer
and typically cost more than simply paving more area for fire truck
access. The result is often large volumes of surface soil that once
grew trees are paved over to support a fire truck’s weight.
LIMITS ON ENFORCEMENT CAPACITY
The lack of a consistent City-wide approach to tree protection
during construction has led to a decline in the urban forest.
Although the City has policies to protect trees during construction,
these are too often overlooked during construction. Building
inspectors who examine the trees on installation and civil
enforcement officers are not arborists trained to spot potential tree
problems. Thus, they are at a significant disadvantage in detecting
issues that may lead to early tree mortality.
Although required by ordinance (2.26.300: Protection of Public
Trees Near Construction Activities), construction sites often
lack fencing or signage related to tree protection. Both Civil
Enforcement and Urban Forestry need additional capacity to
monitor and enforce regulations actively or issue stop-work orders
to correct the situation.
NON-COMPLIANCE WITH
PROTOCOLS FOR NEW TREES
When the zoning code requires new or replacement trees,
the new plantings are often subject to severe stress because
applicants do not follow tree health and irrigation protocols.
Inspectors only determine if the correct number of trees have
been installed and are not trained to evaluate tree health or
planting conditions.
When trees are planted at the height of summer, heat stress
creates difficult growing conditions, resulting in more significant
disease and mortality. Furthermore, once planted, contractors
often do not water during the establishment period, leading to
excessive rates of new tree mortality.
RIGHT-OF-WAY CONFLICTS
Multiple City departments are charged with overseeing land uses
related to public health, safety, and welfare in the right-of-way
(ROW). When land use policies conflict (for example, tree roots with
water lines), insufficient funding means trees often lose out. Tree
loss occurs despite potential solutions which might accommodate
a robust urban forest alongside other land uses.
Simultaneously, there is no clear arbiter for final decisions in the
ROW nor a straightforward process by which different land uses are
allocated. Given the wide streets in many parts of the City’s ROWs,
ample space for trees exists. However, tree planting locations are
sometimes lost due to lack of communication or clear decision-
making authority regarding allocating space in the ROW.
INADEQUATE IRRIGATION
Irrigation considerations are always prominent in Utah’s arid
climate. With a growing population and climate change concerns,
the need for water conservation is ever-present. Currently, the
City will plant trees in park strips at resident request, provided
residents agree to irrigate them. Additionally, the City requires
trees to be preserved or planted for all new development. The
developer is also required to irrigate the trees. In many cases,
however, irrigation never happens or happens for a short period,
leading to the decline and death of trees.
It is challenging to enforce watering requirements. People move,
developers sell properties, and new residents may not be aware,
inclined, or able to meet their responsibilities. As a result, healthy,
viable trees go without sufficient water and never establish and
have a dramatically shortened lifespan.
Furthermore, City maintenance budgets currently limit the amount
of usable irrigation from precipitation, which will be increasingly
important as climate change brings more rain. For example,
the City lacks funds to support the cost of maintaining previous
paving, which would benefit both trees and groundwater supplies.
NON-COMPLIANCE WITH
PROTOCOLS FOR NEW TREES
When the zoning code requires new or replacement trees,
the new plantings are often subject to severe stress because
applicants do not follow tree health and irrigation protocols.
Inspectors only determine if the correct number of trees have
been installed and are not trained to evaluate tree health or
planting conditions.
When trees are planted at the height of summer, heat stress
creates difficult growing conditions, resulting in more significant
disease and mortality. Furthermore, once planted, contractors
often do not water during the establishment period, leading to
excessive rates of new tree mortality.
25
CAPACITY CONSTRAINTS ON URBAN
FOREST MAINTENANCE
Because the urban forest is living infrastructure, its maintenance
needs, while generally predictable, are becoming less so with
climate change. Summer thunderstorms can break tree limbs and
create debris in the right of way, and winter ice storms do the
same – both are increasing as the climate changes. In turn, this
can increase impacts on other infrastructure, such as streets and
aboveground utilities.
LIMITED URBAN FOREST DATA
GATHERING + SHARING
The City lacks a defined schedule for urban forest surveys. Using
GIS and aerial photography, the City has the tools to create and
update canopy cover maps regularly; however, this requires
investment or agreement to share resources with other Utah
government agencies.
The City is possesses reasonably comprehensive and accurate
tree inventory data. However, as this inventory data changes daily,
it is imperative that inventory update strategies be developed and
implemented to ensure lasting data accuracy.
When applicants look at Salt Lake City Maps to determine
project needs and requirements, existing tree and planting
spots are not available.
Additionally, the Urban Forestry Division requires permits for tree
planting and removal, but currently these are difficult to track for a
given year because of past inconsistencies. Further, residents are
often unaware permits are required for park strip trees, and when
they plant or remove trees without a permit, the Urban Forestry
Division does not have a means to track these.
LIMITED RESIDENT ENGAGEMENT
Salt Lake City lacks a balanced public outreach effort that
educates and motivates the community around the urban forest
citywide from residents to business owners.
The City needs data regarding the most effective means of
public outreach and engagement to our residents, including
the approximate number of residents informed about our Urban
Forestry Division’s services and their responsibilities related to
watering street trees.
Many residents are eager to be good stewards of their
neighborhood trees, but the City’s lack of data and capacity to
provide effective outreach creates missed opportunities.
SPECIES OVER-REPRESENTATION
When private property is included, too many Norway maples (Acer
platanoides) are present in the urban forest. The urban forest also
has many green ash (Fraxinus pennsylvanica) and Modesto ash (F.
velutina) trees.
A generally accepted rule is that a single species should never
exceed 10% of the urban forest as a whole and that no genus
should exceed 20%. Norway maple exceeds this rule at the
species level, and the Acer (maple) genus represents 19.9% of Salt
Lake City public trees.
Large park strips can provide ample space for tree roots to grow
when underground utilities are carefully co-located.
26
LOSS OF CLIMATE-RESPONSIVE
DESIGN CULTURE
In the era before air conditioning, the people of Salt Lake
understood the need for shade during the summer months and
planned and legislated accordingly. In 1923, Salt Lake City passed
an ordinance creating a Shade Tree Department, overseen by
the Shade Tree Commission. The Shade Tree Department had
authority over tree planting, pruning, and removal on City lands.
The penalty for violating the ordinance was a $299.00 fine (nearly
$5,000 in 2020) or six months in jail, or both. In the early 20th
century, City officials understood trees as critical components of
Salt Lake City’s urban life.
The loss of climate-responsive design approaches is not unique to
Salt Lake City but has occurred worldwide. Architects abandoned
design responses intended to mitigate weather impacts or
harness the cooling properties of shade and breezes. When
climate control became prevalent, architects designed buildings
where temperatures could adjust with the touch of a dial.
ENVIRONMENTAL INEQUITY
A significant weakness in Salt Lake City’s Urban Forest is related
to a sparser tree-canopy in working-class and industrial areas of
the City, as well as business districts. The lack of trees is most
evident in the West Side (with less than half the canopy cover of
neighborhoods on the east side) and downtown.
Lower tree canopy can intensify adverse public and environmental
health impacts and increase energy costs. Inequity in the urban
forest is common throughout US cities, which several are now
trying to remedy (Los Angeles and Tempe, AZ, for example).
In Salt Lake City, inequity is inadvertently exacerbated because
residents must both request a tree in their park strip and are
required to water it. While this program has many positive
outcomes, this policy generally privileges homeowners. Renters
may feel they need to ask their landlord’s permission or may not
have ready access to a means of irrigation.
For those already cost-burdened by housing, the cost of a
sprinkler system or the time and planning needed to water by
hand simply adds to the burden. And while shade trees can
significantly reduce both energy and water costs to residents, this
is not common knowledge. It is typically 10-15 years from planting
until trees provide adequate shade to houses.
Cost-burdened households then end up in a vicious cycle of
inequity, as they incur physical and economic costs related to
adverse health impacts from hotter summer temperatures and
localized spikes in air pollution. Furthermore, to access trees’
emotional and social benefits, cost-burdened residents are often
required to travel to parks or public lands. In contrast, higher-
income residents are more likely to have trees available when
they look out the window or open the door.
By the 1960s, the widespread adoption of air conditioning
contributed to the notion that urban forests were only
aesthetic and served no real function in US cities.
27
Today, natural systems are increasingly understood as cost-effective solutions in cities to enhance both environmental and public health.
28
This plan defines opportunity in Salt Lake City’s Urban Forest as
factors contributing to growing and preserving the urban forest.
These factors have yet to be explored, acquired, funded, or
implemented. They include assets, policies, skill sets, and other
municipal or resident practices.
Subsequent chapters of this Action Plan will assess some of
these opportunities in more detail and prioritize strategies for
decision-making and implementation.
Opportunities
STRENGTHENING OF TREE
PRESERVATION STRATEGIES +
REQUIREMENTS
There are conflicting directives related to tree preservation
in the Salt Lake City Code. Few fully account for trees’ social
and environmental health benefits. Reassessing these codes
and amending them to remove conflicts and inconsistencies
could resolve these conflicts. In addition, creating urban forest
regulations intended to improve growing conditions, urban
design, and public health would provide multiple environmental
and social benefits.
There are multiple ways to amend the ordinance to strengthen
tree protection and codify ecosystem service value.
The Salt Lake City Open Space Acquisition Strategy, last updated
in 2010, could be revisited to incorporate more specific guidance
related to trees. This guidance should be based on the findings
of more recent analyses of the administration’s urban forest
and goals set. In partnership with scientists and environmental
managers, the City could identify an approach to urban forest
expansion that cleans both the air and the urban watershed.
TREES ARE PUBLIC INFRASTRUCTURE
Cities with thriving urban forests, such as Minneapolis,
understand that trees are critical public infrastructure and plan
and protect them accordingly. Salt Lake City has an opportunity
to investigate and apply a range of policies and practices that
could achieve the goal of elevating the urban forest to the level
of public infrastructure. When trees are valued on par with our
storm-water pipes or streetlights, the City can more easily ensure
an equitable distribution of its benefits.
CREATE COOLING ISLANDS IN GOLF
COURSES + PARKS
Salt Lake City has several opportunities to maximize the “cooling
island effect,” created by parks and golf courses through planting
trees in optimal locations. Research demonstrates that parks cool
ambient temperatures in neighborhoods surrounding them.
Strategically locating large trees on the borders of parks and golf
courses, in collaboration with urban ecologists and atmospheric
scientists, could help mitigate urban heat island impacts as
summers grow hotter.
PLANTING “RIGHT-SIZED” TREES:
CONSIDERING ABOVE + BELOW
GROUND NEEDS
Overhead utility lines often prevent the use of appropriately
scaled trees. In Downtown areas with buildings above three
stories, the City needs taller trees to mediate between the
human and tower scale. Trees do this, and with appropriate
selection can create human-scaled spaces the ROW. In Salt Lake
City’s expansive rights of way, towering trees with generous
canopies promote better urban design and needed shade for
summer cooling.
Electric distribution lines are relatively inexpensive to bury, and
existing trees are usually removed and replaced to bury these
lines. Developing a policy to accommodate buried electric lines,
adequate soil volumes, and soil quality improvement to grow
large trees would add value to developers and residents.
EXISTING PLANTING LOCATIONS
The Urban Forestry Division’s recent inventory identified 36,000
vacant planting sites on City-owned land. A City-led initiative in
partnership with other government agencies and non-profits
could fill those spots. Partners can identify low-water-use tree
species and irrigation infrastructure funding sources to provide
the greatest equity and water conservation benefits. These
planting locations represent the potential to increase the tree
canopy by 600 acres and grow our urban forest by 40%.
29
THE URBAN FOREST’S ROLE IN
URBAN DESIGN + PLACEMAKING
Salt Lake City can link its Urban Forest with urban design
and placemaking to strengthen the City’s image and identity.
Introducing urban forest districts with species selection based
on form and scale would help to define neighborhood character.
Integrating aesthetics and ecological function into plans for the
Urban Forest can creating inviting community spaces.
With a comprehensive approach, planting requirements can
consider physical characteristics, growing needs, regular spacing
for the creation of continuous canopies, visual separation from
moving vehicles for improved perception of safety, and alignment
of street trees to add definition and imageability to neighborhoods
and business districts.
CREATING A RESILIENT
URBAN FOREST
Salt Lake City can create a resilient urban forest that
addresses multiple impacts created by climate change. In
addressing climate change at the local level through urban
forest design and planning, Salt Lake City has a national
opportunity to lead by example.
PUBLIC HEALTH IMPACT MITIGATION + ENVIRONMENTAL JUSTICE
Salt Lake City has an opportunity to link the urban forest with
a broad range of public health outcomes, including improved
outcomes for mental and physical health, and specifically with
respiratory disease. Explicitly relating the urban forest to public
health also presents an opportunity to implement environmental
justice and systemic racism. Trees are an important part of
a strategy to address adverse impacts among historically
marginalized groups disproportionally impacted by poor health.
The City could develop metrics to quantify the effects of tree
plantings on these public health objectives, providing transparent
data to assess whether it is meeting its goals.
ENVIRONMENTAL EQUITY
More shade trees in lower-income neighborhoods can save
energy consumption and address public health concerns related
to urban heat islands and air pollution. The City’s existing tree
planting program can be expanded and revisited to ensure
equitable outcomes. (See Chapter 3, Equity in the Urban Forest,
for examples from other US cities).
INCREASED ACTIVE TRANSPORTATION USE
Introducing shade trees at transit stops and on critical active
transportation routes can make walking, biking, and transit the
most attractive, obvious, and comfortable choice. Making non-
auto transportation modes attractive can reduce the stigma often
associated with taking public transit or walking. More shade could
also make cycling and walking more appealing during the hot
summer months, reducing emissions from private vehicle use.
ENERGY SAVINGS
The 2019 Resource analysis found that SLC saves $1.1 million in
energy consumption annually. As our summers get hotter because
of climate change, the City has an opportunity to locate trees
strategically and increase energy savings substantially.
FOOD ACCESS
Urban forests can be a source of fresh, accessible produce and
an opportunity for education on food and nutrition. Incorporating
collections of food-bearing trees, either as a supplement to
landscaping in parks and playgrounds, as street trees, or in an
orchard format (commonly called a food forest), can be an added
layer of long-term support for communities.
INTEGRATING THE URBAN FOREST INTO
STORMWATER MANAGEMENT STRATEGIES
By storing rainfall on the leaves and branches, trees reduce or
eliminate localized flooding. Tree roots retain soil in place so that
it is not washed away in severe storms. The tree roots keep soil
in place so that it is not washed away in severe storms. Trees
also clean water as it flows through roots and into groundwater.
One hundred mature trees can retain approximately 250,000
gallons of rainwater per year, decrease polluted runoff, and
decrease erosion, improving water quality. Integrating trees fully
into Salt Lake City Stormwater Management practices would
make the City more resilient to climate change-induced summer
precipitation events.
30
EXPANDING BIODIVERSITY IN SALT LAKE
CITY’S PARKS + STREETSCAPES
While there are 200 species of trees within Salt Lake City’s urban
forest inventory, nearly 50% of all public trees consist of seven
species. Salt Lake City can expand the biodiversity of its urban
forest further, providing both habitat and urban design benefits.
Increased biodiversity provides additional insurance against the
risk of large areas of tree die-off created by species-specific threats
due to pests and climate change impacts. Many of the over-planted
species are now nearing removal age. New plantings provide an
opportunity to expand biodiversity on public lands and educate
landowners about the importance of maintaining diverse tree
species on private lands.
IMPROVING HABITAT FOR BIRDS
The City could assess its existing bird habitat, with focus
on important migratory flyways, like the Jordan River, using
commercially available GIS tools, or through partnerships with
institutions or nonprofits. When the assessment is complete, and
habitat revitalization opportunities are identified, the City could
look to the model created by Vancouver, B.C., an “adopt and
promote voluntary Bird Friendly [Urban Forest and] Landscape
Design Guidelines for developers, planners and designers and
public and private landowners.” (City of Vancouver, 2015)
EDUCATION ON IRRIGATION COSTS +
WATER CONSERVATION
Salt Lake City can educate residents on the costs of tree irrigation.
The City can also disseminate information on which species are
low water use and contribute to City water conservation goals.
While the cost of watering varies by tree species, they are typically
lower than expected. Based on the recommended watering
schedule Urban Forestry prescribes, the total cost of watering
trees during the 6-month growing season works out to two dollars
per month. An average, healthy tree uses 225 gallons of water
a week for about half the year. In comparison, a single person
typically uses 700 gallons of water per week all year round.
EDUCATING RESIDENTS ON URBAN
FOREST BENEFITS
Providing education on the urban forest can assist Salt Lake
City with its stewardship. With some education, many residents
could help care for our urban forest. Urban Forestry staff could
provide training like a “Master Gardener” program that results in
neighborhood-based volunteer foresters. These “tree stewards
“could assist with minor tree care, provide best practice advice
to neighbors, and help flag more extensive tree care needs to
urban forestry staff.
INTEGRATING URBAN FORESTRY
INTO SALT LAKE CITY GIS
The Urban Forestry Division maintains a tree inventory in a
proprietary geographic information system (GIS), accessible to the
public on the division’s web page but maintained by a national
arboriculture consultancy.
The City would benefit from improved integration of a tree
inventory data layer into Citymap, Salt Lake City’s publicly
accessible GIS. Ideally, tree inventory data updates should
automatically push to the City’s other GIS mapping software. That
way, applicants and reviewers can consider trees and planting
spaces in the earliest stages of project planning. Sharing the
inventory updates on a regular basis with utility companies, could
help the City anticipate and avoid conflicts.
Currently, no accurate maps of park strip dimensions and other
tree planting locations exist in the City GIS. An accurate survey of
these areas would assist multiple City departments by providing
precise measurements to plan tree planting and additional
sustainable infrastructure measures, including proactive planning
for areas where additional soil volumes are needed.
31
RETHINKING THE ROW:
PLANNING EARLY + ALWAYS
FOR THE URBAN FOREST
Salt Lake City’s rights-of-way represent our largest and most widely
distributed public spaces throughout the municipality. Integrating
space for trees to prioritize the quality of life in these public spaces
could be transformative, both socially and environmentally.
We have many existing large park strips that would give ample
space for large trees, even alleés (double rows) of trees.
Additionally, removing asphalt during road reconstruction and
planting trees could significantly reduce the extent of paved
surfaces and increase asphalt lifespan.
A critical opportunity for the City is to assess all plans and
implementation projects in or adjacent to the ROW alongside
the tree inventory. Proactive planning between the departments
should incorporate the total value of the urban forest. A proper
appraisal of our living infrastructure will retain trees and tree-
planting locations and maintain adequate soil volumes as the
City grows and changes.
SEPTEMBER 2020 WINDSTORM
On September 8, 2020, a windstorm brought hurricane-force
winds that felled more than 1,500 public trees and many more
private trees. While catastrophic, this spotlighted the importance
of the urban forest. People across the City recognized the loss of
large, older trees in parks and neighborhoods. Residents were
moved to donate or volunteer to replant trees. This event may
motivate more residents to become involved in the preservation
and growth of the urban forest and actively seek education on
tree maintenance practices.
DEVELOP AN URBAN FOREST
MANAGEMENT PLAN THAT
INTEGRATES ECOSYSTEM SERVICES
The urban forest’s ecosystem services are incidental to tree
regulations in the Salt Lake City Code and policy. A comprehensive
urban forest management plan that strategically considers all the
benefits trees provide could address environmental impacts. A
management plan could also evaluate multiple factors to prioritize
tree plantings where they are needed most.
PUBLIC-PRIVATE PARTNERSHIPS
The City can continue to explore a range of public-private
partnerships with institutions, corporations, schools, health
care providers, and non-profit organizations. More broadly,
communicating the broad range of the urban forest’s benefits
widens the range of potential partners whose goals may also
be addressed by planting trees. These partnerships present
opportunities to pursue a wide range of grant funding to
implement the recommendations of this action plan.
32
This plan defines Salt Lake City’s Urban Forest constraints as
external or structural factors inherent to planting and managing
trees in urban conditions.
These factors limit the urban forest’s growth and preservation
and may also restrict the City’s ability to effectively utilize the
urban forest’s ecosystem services.
CLIMATE CHANGE
As the climate changes and summer temperatures increase, stress
on trees will also increase. Climate change can contribute to
tree mortality through increased exposure to disease, pests, and
extreme weather events.
To adapt to climate change and increased urban heat island
impacts, the City may need to evaluate its list of preferred
species and make updates on an as-needed basis. Climate
change could also impact the amount of water some public trees
require or require designed microclimates in specific locations to
accommodate beloved species better.
BIOGENIC VOLATILE ORGANIC
COMPOUNDS
Some tree species are high biogenic volatile organic compound
(BVOC) emitters, which can contribute to ozone pollution during
the summer months. According to the City’s recent resource
analysis, “Over 11,173 pounds of BVOCs are emitted annually
from Salt Lake City’s public trees, reducing annual benefits to air
quality by -$2,123.”
While this is a naturally occurring constraint, arborists and
ecologists can mitigate these impacts through species
selection and careful attention to planting locations of BVOC-
emitting species.
PROPERTY DAMAGE
Some degree of property damage is inevitable with trees (and with
precipitation patterns fluctuating due to climate change, this may
increase). And while Urban Forestry removes dead or dangerous
trees, commitment to funding adequate pruning and maintenance
cycles can minimize tree damage and decline.
WATER QUALITY IMPACTS
Increasing the number of trees in Salt Lake City can increase
the volume of leaf litter in our waterways, depriving the aquatic
life of needed dissolved oxygen. Because the Jordan River is a
heavily engineered system in a highly urbanized area located
at the base of a closed watershed, adverse impacts to water
quality can be magnified.
ARID CLIMATE
Salt Lake City’s arid climate, with its hot summers and cold, snowy
winters, creates stressful growing conditions for trees. The City’s
trees need additional irrigation to thrive, unlike those in cities with
abundant precipitation. Our urban forest is mainly hand-planted,
except for along riparian corridors, and requires climate-specific
care to thrive.
WATER CONSERVATION CONCERNS
Water conservation, however, remains vital in Salt Lake City’s
arid climate, and the Urban Forest requires careful planning
and management to achieve adequate protection. Many
well-meaning residents have reduced landscape irrigation to
conserve water, which has resulted in tree death in some cases.
Xeriscaping, the practice of planting primarily low water use
vegetation and zoning plants by water usage, has too often
been misinterpreted as “zero-scaping.” Zero-scaping consists
of placing rocks and perhaps a few plants within park strips and
yards--or laying petroleum-based artificial turf over the soil.
While xeriscaping works with many tree species, “zero-scaping”
and artificial turf increase the urban heat island (UHI) effect,
leading to tree stress. Ultimately, lack of water often results in early
mortality. Much of the discussion of water use and conservation
has been oversimplified as few to no plants providing
conservation benefits.
In addition, residents often desire “no-maintenance” landscapes
or see neighboring “zero-scapes” as a model for their land. These
perceptions will likely continue to result in tree damage and death
in the near term, along with increased UHI.
Educating the public on the role of the urban forest in water
conservation, and importance of tree watering (deeper but less
frequently) is necessary. Shade provided by tree canopy reduces
evaporation, particularly over turf grass, reduces waste and
evaporation and plays a critical part in water conservation.
While a concerted education campaign is essential, the realities
of cost and competing budget priorities impose limits on the City’s
ability to mitigate impacts from “zero-scaping.”
Constraints
33
Livability + the
Urban Forest in
Salt Lake City
Livability is a place-based term, defined in Salt Lake City’s Downtown Plan (2016) as the
capacity of a place to fulfill both daily needs and quality of life needs for residents. Daily
needs are basics required for survival, like food, water, housing, transportation, public
health and safety, sanitation. Quality of life needs must be met for residents to thrive.
Quality of life encompasses the tangible and intangible elements that increase resident
happiness, including arts and culture, recreation, social interaction, community, education,
social equality, and access to nature. Underpinning both daily needs and quality of life
needs is the ability of the community to provide access to good jobs and support a
resilient economy. A livable city is one that provides access and choice to both daily and
quality of life needs to residents and visitors. (Downtown Plan, 2016)
The urban forest contributes to livability by meeting both daily and quality of
life needs, including public health and safety, equity, access to nature, active
transportation routes, and fostering places for social interaction. Without a healthy
urban forest, life in Salt Lake City would be drastically different. n
o
.
3
34
* 2014 the most recent publicly available data set at the time
this plan was created. Given the slow rate at which tree canopy
expands, the data remained applicable in 2021.
Equity is foundational to livability, as attention to both the daily
and quality of life needs of marginalized communities typically
provides benefit to all. The American Planning Association,
describes equity as “just and fair inclusion into a society in which
all can participate, prosper, and reach their full potential.” The
APA notes that “equity is responsive to difference; equitable
policies actively mitigate the disproportionate harm faced by
certain communities.” (APA, 2021)
As the national non-profit Partners for Livable Communities
notes, “A community that satisfies the full range of its residents’
needs is more attractive as a place to live, work and do business
and, therefore, more likely to be economically successful.”
(Partners for Livable Communities, 2021)
The distribution of tree canopy cover is a useful frame of
reference to evaluate urban equity. Given the wide range of
benefits the urban forest provides, from improved local air
quality and public health to increased property values and
retail sales, the distribution of canopy cover is a useful metric
to assess which neighborhoods have the greatest and least
access to those benefits.
Planning undertook GIS analysis of canopy cover per 10-acres
of land area (the size of a downtown city block) based on U.S.
Environmental Protection Agency land cover data from 2014.*
Equity
The analysis reveals an uneven distribution of tree canopy
across the city, and one that correlates closely to other
documented inequities in Salt Lake City.
While some of the distribution of trees may be attributed to their
“natural” pattern of growing predominantly along waterways and
north-facing slopes this eco-region, it cannot account for most
of it. Note that urban-scale tree planting in Salt Lake City began
nearly two centuries ago, and multiple factors influence when
and where trees are planted in the city.
The GIS analysis below divides the city into master plan areas
for the purposes of comparing primarily residential districts. Tree
canopy cover was notably greater in residential areas east of
approximately State Street with the prominent exception of the
Downtown Plan area.
The Downtown Plan area is one of the most heavily paved
in the city, with the most difficult growing conditions for
trees. Downtown has seen an unprecedented rate of new
development in the past decade, which often leads to tree
removal and replacement with young trees and may be a
contributing factor to its low canopy level.
¯
City Creek
Airport
Northwest
Quadrant
Capitol Hill
Avenues
East BenchCentral
Community
Westside
Sugar House
Northwest
Downtown
Salt Lake City Tree Canopy Cover by Master Plan Area (2014 EPA vegetation data). East side areas have approximately twice
the canopy as the those on the west side, and an average of four times the canopy present in the Downtown Plan area.
0 - 473
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1735 - 3300
ACS Population Less than 18 Years
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Tree Cover per 10 Acre hexagon
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80 - 100%
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City Creek
Airport
Northwest
Quadrant
Capitol Hill
Avenues
East BenchCentral
Community
Westside
Sugar House
Northwest
Downtown
35
Surface Temperature by Master Plan Area
100 F˚
100.1 - 115 F˚
115.3 - 118 F˚
118.3 - 123 F˚
0 3.5 7
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Quadrant
Northwest
City Creek
Airport
Capitol Hill
Avenues
East Bench
Central
CommunityWestside
Sugar House
Northwest
Downtown
Salt Lake City Surface Temperature by Master Plan Area (temperature measured on July 31, 2020 at 5:05 pm
local time by NASA’s ECOSTRESS satellite). Lower temperatures correlate to areas with more tree canopy, and vice versa.
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
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Surface Temperature by Master Plan Area
100 F˚
100.1 - 115 F˚
115.3 - 118 F˚
118.3 - 123 F˚
0 3.5 7
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Quadrant
Northwest
City Creek
Airport
Capitol Hill
Avenues
East Bench
Central
CommunityWestside
Sugar House
Northwest
Downtown
THE LEGACY OF REDLINING IN
SALT LAKE CITY’S URBAN FOREST
In cities throughout the United States, persistent socio-
economic divides in investment and development patterns
correlate to the historic practice of redlining. Briefly, redlining
is the term commonly used to describe federal, state, and
local government policy during the New Deal era of the 1930s,
in which policy-makers designated the “quality” of areas for
loans provided via the Home Owners Loan Corporation (or
HOLC). In practice, this was used to reinforce segregation
and discrimination in neighborhood patterns by designating
areas of residential settlement based on race, ethnicity, and
socioeconomic class. Areas consigned to “the wrong side of
the tracks,” were labeled “D-hazardous” and shown in red on
maps, hence the term “redlining.”
The legacy of these discriminatory practices is present in the
inequitable distribution of wealth and access in cities throughout
the United States, and Salt Lake City is no exception. Households
with the highest median income live on the east side of the city,
while the lowest income households are located predominantly
on the formerly redlined west side.
Just as the pattern of racial, ethnic, and economic inequalities
persist in urban areas nearly a century after redlining policies
were created in the US, the distribution of urban forest cover
often reflects those same inequities. Typically, wealthier
communities have greater tree canopy, and therefore more
access to the range of benefits the urban forest provides.
Salt Lake City redlining map, c. 1935 (Mapping Inequality)
A 2020 study of 37 US cities looked at urban forest distribution
and HOLC (or redlining) maps, found that areas designated “A”
(typically reserved for US-born white populations) had nearly
double the tree canopy cover than those designated “D” for
people of color. (Locke, 2021)
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A
A
A
B
B B
B
BB
C
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CC
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C
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DD
D
D
D
D
D D
D
HOLC Category + Percent Canopy
A -
B -
C -
D -
28 - 40%
20 - 27%
9 - 19%
6 - 8 %Percent tree cover (EPA, 2014) by HOLC graded areas in Salt Lake City. Redlined areas (D) have the lowest amounts of tree canopy.
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DD
D
D
D
D
D D
D
HOLC Category + Percent Canopy
A -
B -
C -
D -
28 - 40%
20 - 27%
9 - 19%
6 - 8 %
This phenomenon is apparent in Salt Lake City as well, with
some “A” areas having more than six times the tree canopy of
those once designated “D.” For a fuller accounting of inequities
in urban forest distribution in the United States see the American
Forests Tree Equity Score website.
Salt Lake City’s street tree planting policy is to provide them
free of charge to residents, on the condition that they agree
to water them. This is a popular program for residents who are
aware of and appreciate the benefits trees provide, but still leave
a significant number of street tree planting locations vacant
and assume that residents are aware of the needs and costs
associated with watering.
An equitable distribution of free trees in Salt Lake City will likely
require a significant campaign on both the importance of the
urban forest as well as water use and costs to maintain healthy
trees. Trees generally use much less water than people assume,
while also conserving water by reducing evaporation for the
vegetation that they shade.
An average mature tree uses 70 gallons of water weekly, while
an average adult uses ten times that amount. During the 8-month
growing season, monthly costs to water a tree range from $0.10
for a young tree to $ 0.70 for a mature tree.
Sprinkler costs, however, can create a larger burden on low-
income residents, as installation and power expenses are a
larger share of their income than higher income residents. For
those who do not have sprinkler systems, the time required
to provide the deep, slow watering that helps trees thrive can
also represent a burden.
Rising housing rates and rents have made resident turn over
more frequent in Salt Lake City. As home ownership or rentals
change occupants, new residents may not be aware of their
irrigation responsibilities. Further, renters may assume that tree
requests and irrigation are the responsibility of the landlord,
leading to trees going without water for prolonged periods,
resulting in decline and death.
LEGACY OF REDLINING ON THE
URBAN HEAT ISLAND EFFECT
Increasing temperatures due to climate change have a direct
impact on livability, as do temperature impacts created by
many urban surface materials, notably asphalt. Land Surface
Temperature is measured by satellite and is a measurement of
how hot a given surface feels to the touch, the data is made
available by NASA. The difference in Land Surface Temperature
37
A
A
A
A
B
B B
B
BB
C
C
CC
C
C
C
C
C
DD
DD
D
D
D D
D
A -
B -
C -
D -
HOLC Category + Surface Temperature
111 - 113 F˚
113.1 - 115 F˚
115.6 - 117 F˚
117.9 - 122 F˚
0 3.5 7
Miles
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Land surface temperature by Salt Lake City HOLC graded areas (NASA ECOSTRESS, July 31, 2020 at 5:05). Areas that were
redlined (grade D) and grade C (“definitely declining”) have the highest surface temperatures nearly a century later.
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HOLC Category + Surface Temperature
111 - 113 F˚
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115.6 - 117 F˚
117.9 - 122 F˚
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(LST) shown in the map below is the difference in mean
temperature for within formerly HOLC-graded (or redlined)
areas from the mean temperature for all HOLC-graded areas
in Salt Lake City. Again, as with other cities in the US, there is a
correlation between higher temperatures and redlined areas.
Although air temperature is the gold standard for
demonstrating thermal comfort and increased potential for
adverse health impacts, this data was not available at the
neighborhood or block scale in Salt Lake City.
Although land surface temperatures do not directly correlate
to thermal comfort (which requires local air temperature
measurements), it does provide some guidance to understand
which areas of the city may be likely to have increased heat-
related impacts and demonstrate which locations are most in
need of shade. Land surface temperature is also an indicator
of areas where vegetation is likely to experience heat stress,
which has significant impacts on the health and longevity of
the urban forest.
Furthermore, the impact of rising temperatures due to climate
change are magnified by urban heat island effect and have
significant adverse impacts on human health.
Salt Lake City’s poor winter air quality tends to get a greater
share of the public’s attention, in part because of the visible
smog created by particulate matter (PM2.5). Summer air quality,
and its relationship to the urban heat island, however, is of
increasing concern in the city.
Nitrogen oxides (NOx), primarily caused by vehicle emissions,
react with volatile organic compounds (VOCs) during sunny, hot
weather and lead to the creation of ozone (O3). (https://www.epa.
gov/heat-islands/heat-island-impacts, accessed July 2019)
Ozone pollution can trigger respiratory problems,
including lung inflammation and asthma attacks, along
with heart attacks.
The EPA’s current air quality standard for ozone is 0.075 ppm,
although some EPA scientists recommend lowering this to 0.06
ppm to protect children’s developing lungs from its negative
effects. The World Health Organization recommends an even
lower ozone standard of 0.053 ppm. (Kenward, 2014)
Although the Clean Air Act has provided improvements in ozone
levels, these gains may be threatened by increased heat caused
by climate change.
38
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11 - 20 %
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27 - 36 %
Tree Cover Percent by Census Tract
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27 - 36 %
Tree Cover Percent by Census Tract
Salt Lake City tree canopy cover EPA 2014) by census tract. Tracts: U.S. Census Bureau 2019 American Community Survey (ACS).
DEMOGRAPHICS
Demographic analysis demonstrates that a lack of tree cover
is correlated to neighborhoods with higher concentrations of
people living in poverty, people of color, and numbers of children
in Salt Lake City.
Access to tree cover in residential areas is generally less
in areas with higher concentrations of poverty (see above
right), meaning the livability factors enhanced by trees are
inequitably distributed.
The pattern in Salt Lake City mirrors that found in cities
throughout the United States, where wealthier areas have
twice the canopy of their lower-income counterparts. This
holds true in neighborhoods with higher numbers of people of
color as well.
Poverty and systemic racism are both contributors to poor health
outcomes, up to and including shorter life spans, as they are
significant stressors. Enhanced livability through an expanded
urban forest will not, on its own, solve these problems, but can
become an significant part of the solution through the many
benefits it provides.
39
1 - 10 %
10 - 15 %
15 - 25 %
25 - 41 %
SLC Population Below Poverty Level in the Past 12 Months
0 3.5 7
Miles
¯
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
0
-
4
7
3
47
4
-
1
0
1
5
10
1
6
-
1
7
3
4
17
3
5
-
3
3
0
0
AC
S
P
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p
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l
a
t
i
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L
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1
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a
r
s
0
3.
5
7
Mi
l
e
s
¯
1 - 10 %
10 - 15 %
15 - 25 %
25 - 41 %
SLC Population Below Poverty Level in the Past 12 Months
0 3.5 7
Miles
¯
¯
0 3.5 7
Miles
ACS Population by Race
Non-Hispanic White
Hispanic or Latino
Black or African American
Asian
American Indian and Alaska Native
Two or More Races
Native Hawaiian and Other Pacific Islander
Other Race
Predominant racial or ethnic group by census tract (2019 ACS).
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
0
-
4
7
3
47
4
-
1
0
1
5
10
1
6
-
1
7
3
4
17
3
5
-
3
3
0
0
AC
S
P
o
p
u
l
a
t
i
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L
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n
1
8
Y
e
a
r
s
0
3.
5
7
Mi
l
e
s
¯
¯
0 3.5 7
Miles
ACS Population by Race
Non-Hispanic White
Hispanic or Latino
Black or African American
Asian
American Indian and Alaska Native
Two or More Races
Native Hawaiian and Other Pacific Islander
Other Race
5%
2%
1%3%
3%
22%
64%
Percent of population whose income was below the poverty level in the past 12 months, by census tract (2019 ACS).
40
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
Asthma Prevalence (%)
8 %
9 %
9 - 10 %
10 - 11 %
0 3.5 7
Miles
¯
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
0
-
4
7
3
47
4
-
1
0
1
5
10
1
6
-
1
7
3
4
17
3
5
-
3
3
0
0
AC
S
P
o
p
u
l
a
t
i
o
n
L
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s
s
t
h
a
n
1
8
Y
e
a
r
s
0
3.
5
7
Mi
l
e
s
¯
Asthma Prevalence (%)
8 %
9 %
9 - 10 %
10 - 11 %
0 3.5 7
Miles
¯
Percent of population under 18 years old by census tract (2019 ACS).
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
0
-
4
7
3
47
4
-
1
0
1
5
10
1
6
-
1
7
3
4
17
3
5
-
3
3
0
0
AC
S
P
o
p
u
l
a
t
i
o
n
L
e
s
s
t
h
a
n
1
8
Y
e
a
r
s
0
3.
5
7
Mi
l
e
s
¯
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
The greatest numbers of children in Salt Lake City live on the
west side and are therefore more likely than their east side
counterparts to experience the adverse impacts to livability
associated with lower canopy cover.
Asthma rates are also significantly higher in areas with fewer
trees, higher poverty, and more children. Studies have shown
a relationship between lower rates of childhood asthma in
neighborhoods with more trees (Vibrant Cities Lab).
Percent of population with asthma by census tract, from the Center for Disease Control’s (CDC) 500 Cities program.
41
Energy Burden (percent of income)
1 %
1 - 2 %
2 - 3 %
3 - 4 %
0 3.5 7
Miles
¯
CDC 500 Cities - Lack of Health Insurance Prevalence (%)
6.6 - 11.4%
11.41 - 16.1%
16.11 - 22.5%
22.51 - 36.6%
0 3.5 7
Miles
¯
Percent of population without health insurance by census tract (CDC’s 500 Cities program).
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
0
-
4
7
3
47
4
-
1
0
1
5
10
1
6
-
1
7
3
4
17
3
5
-
3
3
0
0
AC
S
P
o
p
u
l
a
t
i
o
n
L
e
s
s
t
h
a
n
1
8
Y
e
a
r
s
0
3.
5
7
Mi
l
e
s
¯
CDC 500 Cities - Lack of Health Insurance Prevalence (%)
6.6 - 11.4%
11.41 - 16.1%
16.11 - 22.5%
22.51 - 36.6%
0 3.5 7
Miles
¯
Energy Burden (percent of income)
1 %
1 - 2 %
2 - 3 %
3 - 4 %
0 3.5 7
Miles
¯
The prevalence of pulmonary disease on the west side is
compounded by a lack of health insurance. Strategic tree
planting guided by demographic information, and using species
known to mitigate targeted pollutants may provide improved
health outcomes for many in these communities. Energy burden,
or the costs of energy as a percentage of gross income, also
creates strain on lower income households that could be
mitigated through tree planting. Strategic placement of trees
near buildings lowers energy usage, contributing to fewer
greenhouse gas emissions an average of 5% savings on energy
costs (Vibrant Cities Lab, 2014).
Figure 10. Energy Burden, by census tract, from the from the U.S. Census Bureau 2019 ACS.
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
0
-
4
7
3
47
4
-
1
0
1
5
10
1
6
-
1
7
3
4
17
3
5
-
3
3
0
0
AC
S
P
o
p
u
l
a
t
i
o
n
L
e
s
s
t
h
a
n
1
8
Y
e
a
r
s
0
3.
5
7
Mi
l
e
s
¯
Energy Burden (cost of energy relative to household income) by census tract (2020 energy data; 2019 ACS census tracts)
42
¯
0 3.5 7
Miles
1 - 11 %
11 - 20 %
20 - 27 %
27 - 36 %
Tree Cover Percent by Census Tract
Salt Lake City Tree Canopy Cover
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
0
-
4
7
3
47
4
-
1
0
1
5
10
1
6
-
1
7
3
4
17
3
5
-
3
3
0
0
AC
S
P
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p
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i
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1
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Y
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a
r
s
0
3.
5
7
Mi
l
e
s
¯
¯
0 3.5 7
Miles
1 - 11 %
11 - 20 %
20 - 27 %
27 - 36 %
Tree Cover Percent by Census Tract
Salt Lake City Census Tract Analysis
¯
0 3.5 7
Miles
108 - 112° F
112 - 115° F
115 - 118° F
118 - 121° F
Surface Temperature by Census Tract - July 31
Salt Lake City Surface Temperature (5:05 p.m. MDT, July 31, 2020)
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
0
-
4
7
3
47
4
-
1
0
1
5
10
1
6
-
1
7
3
4
17
3
5
-
3
3
0
0
AC
S
P
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a
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i
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1
8
Y
e
a
r
s
0
3.
5
7
Mi
l
e
s
¯
¯
0 3.5 7
Miles
108 - 112° F
112 - 115° F
115 - 118° F
118 - 121° F
Surface Temperature by Census Tract - July 31
2019 AMERICAN COMMUNITY SURVEY (ACS) TRACT DATA
43
Asthma Prevalence (%)
8 %
9 %
9 - 10 %
10 - 11 %
0 3.5 7
Miles
¯Population 2014
1392 - 2718
2719 - 4091
4092 - 5775
5776 - 8098
0 3.5 7
Miles
¯
Energy Burden (% income)
1 %
1 - 2 %
2 - 3 %
3 - 4 %
0 3.5 7
Miles
¯0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
CDC 500 Cities - Lack of Health Insurance Prevalence (%)
7 - 11 %
11 - 16 %
16 - 23 %
23 - 37 %
0 3.5 7
Miles
¯
1 - 10 %
10 - 15 %
15 - 25 %
25 - 41 %
SLC Population Below Poverty Level in the Past 12 Months
0 3.5 7
Miles
¯
Population 2014
1392 - 2718
2719 - 4091
4092 - 5775
5776 - 8098
0 3.5 7
Miles
¯
0 - 473
474 - 1015
1016 - 1734
1735 - 3300
ACS Population Less than 18 Years
0 3.5 7
Miles
¯
CDC 500 Cities - Lack of Health Insurance Prevalence (%)
7 - 11 %
11 - 16 %
16 - 23 %
23 - 37 %
0 3.5 7
Miles
¯1 - 10 %
10 - 15 %
15 - 25 %
25 - 41 %
SLC Population Below Poverty Level in the Past 12 Months
0 3.5 7
Miles
¯
Energy Burden (% income)
1 %
1 - 2 %
2 - 3 %
3 - 4 %
0 3.5 7
Miles
¯
Asthma Prevalence (%)
8 %
9 %
9 - 10 %
10 - 11 %
0 3.5 7
Miles
¯
Asthma Prevalence (%)Salt Lake City Total Population
Energy Burden (% Income)Population Less than 18 Years
CDC 500 Cities - Lack of Health InsurancePopulation Below Poverty Level (Last 12 Months)
44
Environment
The urban forest has an important role to play in many aspects of
livability, but for cities one of the greatest returns on investment
can come in the form of improved public health outcomes. To
determine the scale and ongoing commitment to investment
necessary to equitably distribute these improved outcomes,
it is first necessary to quantify the number of trees and other
vegetation required.
TREES NEEDED TO MITIGATE
URBAN HEAT ISLAND EFFECT
Trees help cool urban areas by physically shading spaces
and by cooling the air as they release moisture through
transpiration. Selecting the right tree is important as its physical
form determines how much sunlight can pass through to hit
the ground below the canopy. Researchers at the University
of Wisconsin found that a typical city block needs to have at
least 40% canopy coverage to reduce the daytime summer air
temperature. (Ziter, 2019) The 40% canopy threshold resulted in
a temperature decrease of 7-9 degrees Fahrenheit.
TREES NEEDED TO MITIGATE
AIR POLLUTION
According to data published by the American Lung Association,
the Salt Lake City-Provo-Orem area ranked No. 11 for ozone
pollution and No. 7 for short-term particulate pollution in the
United States. According to the nonprofit organization Saving
Nature, it takes roughly 1,025 trees to offset the average
American’s yearly emissions, with each tree absorbing about 31
pounds of carbon dioxide per year. (Add citation)
With approximately one of every nine deaths being contributed
to poor air quality, a robust and diverse urban forest is one
means to offset pollution and in turn, promote human health
(World Health Organization, 2016). The amount of pollutants
and particulates filtered by each tree vary depending on its
placement and composition. Cities need to consider multiple
variables including the tree’s mature size, growth rate, and the
architecture of the tree such as its canopy structure, leaf size and
the texture of the leaves. By integrating these criteria into urban
design and urban forestry policies and ordinances, Salt Lake City
could demonstrably address poor air quality impacts while also
enhancing multiple quality of life needs.
TREES NEEDED TO MITIGATE
STORMWATER IMPACTS
Trees are important in stormwater management due to their
ability to take up water through their roots and leaves and slow
the flow of stormwater through the utility system. As detailed in
Chapter 2, there are roughly 86,500 publicly owned trees in Salt
Lake City, which cover just over 2% of the City’s total land area.
A University of Utah study found that stormwater runoff could
be reduced by 12% if every house in a typical Salt Lake City
single-family home neighborhood collected 2,500 gallons of
rain water per year (Steffen, 2013), which is about the equivalent
interception capacity, or “the sum of canopy surface water
storage and evaporation,” of one medium-sized tree (Center for
Urban Forest Research, 2002).
Planting trees in just half of the currently available locations
on City streets would intercept 30 million gallons (or 4 million
cubic feet) of rainwater. This would dramatically reduce the
amount of stormwater runoff entering the stormwater system,
which is one of the most significant polluters of our waterways.
Clean water is vital to livability, one that obviously meets daily
needs but also greatly enhances quality of life needs related to
recreation, in particular the lake effect impact on winter sports
opportunities among the Wasatch peaks.
WATER CONSERVATION +
THE URBAN FOREST
Trees can be an important part of water conservation strategies
provided there is education as to which species are water wise,
or drought tolerant, and how best to water trees. For example,
shaded lawn uses much less water than unshaded lawns,
resulting in efficient water use.
With the pressing need for water conservation due to increased
population and climate change, models can be used to forecast
which areas should receive the most sustained investment in
the urban forest, and which methods of urban heat mitigation
and water conservation will provide greater return on investment
(Jones, 2018). In all cases, trees should be considered an
important tool in the water conservation toolkit, while evaluating
how to pair the urban forest with other types of infrastructure to
conserve water.
45
SALT LAKE CITY URBAN FORESTRY
ORDINANCE
In September of 1988, Salt Lake City amended Chapter 2.26 of
the Salt Lake City Code to be entitled the “Salt Lake City Urban
Forestry Ordinance”, defining responsibilities and establishing
standards and specifications for the City’s Urban Forest.
Chapter 2.26 aimed to generate coordinated intra-department
regulatory efforts and provide a single point of contact for
residents to consult with any tree related concerns or questions.
The implementation of the amended urban forestry code
resulted in new regulations surrounding the protection and
responsibility of street trees, public nuisance, and designation
of responsible party, while maintaining regulations on all street,
park, and City trees.
Ordinance
HISTORY OF SALT LAKE CITY’S
URBAN FORESTRY + TREE
RELATED ORDINANCE
Several city policy documents guide tree protection,
preservation, and maintenance within Salt Lake City (See
Appendix # for documents). Standards and specifications for
the City’s Urban Forest are contained in the Urban Forestry
Ordinance and the Zoning Ordinance.
Require the protection of existing trees in landscaping for the
design of large projects,
Address the health of street trees and height limits for both
plants and structures in park strips.
The Landscape BMPs and Plant List documents are referenced
within the amended landscaping regulations to provide
clarification on the landscaping standards, including how to
achieve greater water efficiencies, improve stormwater quality,
and enhance water resource protection.
Additionally, Chapter 21A.48 set in motion a coordinated effort for
permitting landscape plans in development situations between
other city departments and Urban Forestry. Under Chapter
21A.48, tree preservation requirements in development situations
were expanded to be more inclusive to all types of development.
Tree protection and preservation requirements on private
development are reviewed and approved by Urban Forestry. On
development projects Urban Forestry issues and inspects tree
preservation requirements.
TREES IN SALT LAKE CITY’S ZONING
ORDINANCE
In April of 1995, Salt Lake City adopted a new Zoning Ordinance
that established certain standards for landscaping and
encouraged the use of drought-tolerant plants. The intent of
these changes was to encourage sustainable design in all
aspects of landscape planning, from residential and commercial,
to public and institutional.
In 2003, after five years of continuous drought, best
management practices (BMPs) were developed to increase
water efficiency in the landscape, incorporating new
technologies in irrigation, and identifying measurable water-use
goals and practices. The plant list was also updated to reflect
current availability and clarify species identification.
In April 2016, Salt Lake City amended sections of the
City’s landscaping requirements under Chapter 21A.48 to
establish water-efficient landscaping, park strip landscaping,
landscape yards, and tree protection regulations. The adopted
amendments were designed to:
Reduce water consumption through grouping plants with similar
watering needs together and ensure efficiencies in the irrigation
system design upon installation.
RELATED DOCUMENTS
The following page shows examples from supporting documents
intended to aid Salt Lake City in the evaluation of landscaping
requirements throughout the city to ensure urban forestry
resources are managed carefully and efficiently.
46
CENTER FOR WATERSHED
PROTECTION RECOMMENDATIONS
PLANT LIST AND HYDROZONE TREE PROTECTION AND
PRESERVATION POLICY
The Landscape Best Management
Practices manual identifies and
outlines standards to enhance
water efficiency, reduce landscape
chemical dependence, and eliminate
water waste for landscapers or
contractors working within the Salt
Lake City area.
The Salt Lake City Plant List
serves as a guide to the public and
landscape professionals for selection
of a wide variety of plants suitable
for water-wise and sustainable
landscapes, while fostering
creativity in planting design.
A set of guidelines for
implementation of tree protection
and preservation prior to
construction work.
LANDSCAPE BMPS FOR
WATER RESOURCE EFFICIENCY
AND PROTECTION
The Center for Watershed Protection (CWP), a national non-
profit focused on stormwater management and watershed
planning, with expertise on the impacts of development on urban
waterways, created a tool to audit municipal ordinances. This
worksheet, “Making Your Community Forest-Friendly,” is based
on best practices in the urban forest, with an understanding that
the urban forest plays a critical role in maintaining the health of
waterways. The tool is intended “to help communities evaluate
their local development regulations to identify revisions that will
better promote protection and management of trees and forests
as well as tree planting.” (CWP, 2018)
While Salt Lake City’s Code employs best practices in roughly
70% of the areas the CWP identified, a few sections of the code
(below) that could be amended to provide stronger protections
to sustain and grow Salt Lake City’s urban forest.
The bulk of CWP’s recommended code and related policy
updates fall within the purview of the Zoning Chapter (Title
21A), while the others may potentially apply to the Streets and
Sidewalks (Title 14), Parks and Recreation (Title 15), and Public
Services (Title 17) chapters.
47
STREETS + SIDEWALKS (TITLE 14)
• Consider specifications for street trees that require trees
with large canopies, provided they do not interfere with
overhead utilities.
• Any requirements for large trees should include related
ordinance for soil volume and soil quality to be effective.
• Consider requiring above ground utilities to be placed
below ground, under the carriageway, to reduce conflict
with trees and allow cities to maximize the benefits the
urban forest provides.
• Consider requiring landscape islands in cul-de-sacs to
reduce stormwater runoff impacts to water quality and
provide a neighborhood amenity.
PARKS + RECREATION (TITLE 15)
• Consider developing or enhancing definitions for priority
natural resources to conserve, and creating an ordinance
addressing access between neighborhood open spaces
and natural lands (e.g., trails).
PUBLIC SERVICES (TITLE 17)
DIVISION III: STORMWATER SEWER SYSTEM
• Consider providing credits for green infrastructure or low-
impact development practices that include tree planting.
(These credits are typically based on the overall volume
of stormwater reduced on-site or mitigated through
investment off-site).
• Consider providing credits for forest conservation or to
increase vegetative buffers along waterways (which has the
added benefit of creating options to develop parcels that
have challenges to treat stormwater on-site).
• Consider incorporating trees into stormwater BMPs to
reduce runoff, enhance water quality, and provide habitat.
• Consider developing stormwater design manuals that
include requirements for species selection and relevant
planting practices to address difficult growing conditions
created by stormwater impacts.
ZONING (TITLE 21)
BUFFERS (21A.34: RIPARIAN CORRIDOR/LOWLAND
CONSERVANCY OVERLAY)
• Consider amending minimum stream buffers in all areas
to 50 feet (this applies to Area A in the Riparian Corridor
Overlay and the Natural Vegetation Buffer Strip in the
Lowland Conservancy Overlay)
• The buffer ordinance should specify that a minimum
percentage of the buffer be maintained with tree cover
suited to the conditions of the growing site.
• Specify enforcement mechanisms within the ordinance.
PARKING LOTS (21A.44)
• A minimum width of 6 feet or greater is recommended
for standard parking lot islands.
• Ensure sufficient space remains available for large trees
by specifically allowing alternative layouts that cluster
trees and provide for shared soil space.
• Allow flush curbs and/or curb cuts and depressed
landscaped areas so that runoff can be directed into
landscaped islands.
• Allow vegetated stormwater management areas to
count toward required landscape minimums.
LANDSCAPING (21A.48)
• Ensure all landscape areas required by zoning
include trees.
• Provide a planting formula for trees, which “may take the
form of a minimum number of trees, number of trees per
parking area, trees per square feet of developed space
or building footprint, density of trees, or percent canopy
coverage.” (CWP, 2018)
• Develop tree planting guidelines (like SLC’s Engineering
Design Guidelines) referenced in the landscaping chapter
that include specifications and standards for:
• tree selection,
• planting,
• size requirements,
• soil type,
• soil volume,
• nursery stock,
• selection, and
• long-term maintenance.
48
SUSTAINABLE CODE REVIEW
RECOMMENDATIONS FOR THE
URBAN FOREST
The recommendations of the 2020 Sustainable City Code
Review are organized into five goals, all of which have a
relationship to the urban forest. The three goals that are most
directly relevant, however, are discussed here.
GOAL 1: REDUCE URBAN HEAT ISLAND EFFECT
The document recommends preserving and expanding the
urban forest to address urban heat island impacts, specifically:
• Expanding tree protections in City code
• Improve parking lot shading standards
Sacramento, CA uses a performance-based parking lot shading
ordinance to mitigate heat islands. In addition to the standards
in the ordinance, Sacramento also employs design guidelines to
provide additional direction related to trees in parking lots.
GOAL 2: INCREASE EFFECTIVENESS OF PUBLIC
RIGHTS-OF-WAY
The document examines the multiple opportunities for expanding
sustainable practices in Salt Lake City’s large rights-of way,
including specifics related to the urban forest:
• Incorporating tree trenches into the City Complete
Streets Ordinance, which “direct stormwater runoff
beneath the surface to gravel pits that allow water to
slowly infiltrate” into groundwater sources.
• Co-locating or vaulting utilities to minimize conflicts
with tree root zones.
• Using San Antonio’s ROW tree protection
ordinance as a model to expand existing tree
protections in Salt Lake City’s code.
GOAL 5: PROMOTE ECOSYSTEM
CONSERVATION DESIGN
The document recommends consolidating information related
to the urban forest in a single chapter and references the
Longmont Colorado City Code as a model. Longmont code
has a chapter dedicated to Trees and Plants, under Title 13:
Streets, Sidewalks and Public Places. The chapter incorporates
requirements related to:
• spacing between trees and utilities
• disease inspection and survey
• tree protection and preservation, and
• replacement or mitigation of removed trees.
(Salt Lake City Department of Sustainability, 2020)
49
Urban Design
Urban design that integrates the urban forest into streets and
publics enhances livability for all residents of a city, both through
principles of environmental psychology and biophilia put into
practice by design, and through incorporating and enhancing the
ecosystem services trees provide.
Of particular importance to Salt Lake City is incorporating
human scale elements into our wide streets, which the urban
forest does, along with providing visual interest and much
needed shade to mitigate the impacts of urban heat island effect.
STREET TREE FORM + SCALE
Given Salt Lake City’s large scale right of ways and oversized
blocks in many parts of the city, the scale and form of trees
becomes more significant. For example, on a narrow street
with limited solar access, columnar trees may provide effective
streetscape design. On very wide streets, however, columnar
trees appear small and out of place, and do not provide
adequate shade unless planted very closely together. However,
a hedgerow of street trees is impractical and difficult to maintain,
in addition to being poor urban design.
Scale requirements for trees also have cost saving
implications, such as providing shade to streets to extend the
lifespan of the asphalt.
COMPARATIVE STREETSCAPES BY
MASTER PLAN AREA
The photographic comparisons on the following pages were
developed by the Planning and Urban Forestry Divisions.
Streets photographed were selected to represent the
“average” streetscape for both high and low canopy areas in
each of Salt Lake City’s Master Plan areas. The photos were
taken by Planning Division staff in August and September 2021.
There are significant differences between areas, particularly
with the provision of shade between high canopy areas.
Consistent with the GIS map analysis, high canopy streets
on the east side have a more extensive, fuller canopy than
their counterparts on the west side. When looking at the
comparative photos, note factors such as:
• tree height
• width and fullness of canopy
• ground area in shade or sun
• size of park strip (soil volumes available for street trees)
• number of trees on private property
• presence or absence of aboveground utility lines
Vase-shaped or spreading canopies shade sidewalks,
creating a comfortable, human-scale sense of enclosure.
The scale and proportion of columnar species is unsuited to the
urban context and they typically provide little or no shade.
50
East Bench Community Master Plan Area - High Canopy (Michigan Ave)
East Bench Community Master Plan Area - Low Canopy (Ambassador Way)
STREETSCAPES BY MASTER PLAN AREA
51
Northwest Master Plan Area - High Canopy (Prosperity Avenue)
Northwest Master Plan Area - Low Canopy (Rose Park Lane)
52
Sugar House Master Plan Area - High Canopy (1800 East)
Sugar House Master Plan Area - Low Canopy (2700 South)
53
Westside Master Plan Area - High Canopy (1000 South)
Westside Master Plan Area - Low Canopy (Redwood Road)
54
Avenues Master Plan Area - High Canopy (Second Avenue)
Avenues Master Plan Area - Low Canopy (Twelfth Avenue)
55
Downtown Master Plan Area - High Canopy (Main Street)
Downtown Master Plan Area - Low Canopy (700 South)
56
Central Community Master Plan Area - High Canopy (Yale Avenue)
Central Community Master Plan Area - Low Canopy (Grove Avenue)
57
Capitol Hill Master Plan Area - High Canopy (De Soto Street)
Capitol Hill Master Plan Area - Low Canopy (800 North)
58
When planted to cast shade on building windows and sidewalks, trees reduce energy use and cool pavements
59
BEST MANAGEMENT
PRACTICES FOR A
THRIVING URBAN
FOREST
The Best Management Practices explored in this chapter relate to Planning, Urban
Design, and Land Use policy and practice. They intentionally fall outside Salt Lake City’s
Urban Forestry Division’s remit and do not address tree care. These best practices are
models Salt Lake City can use to develop the urban forest as public infrastructure and
effectively reap the multiple benefits it provides.
This chapter provides evidence-based solutions for future land use and urban
design decision-making related to the urban forest in Salt Lake City, with
adaptation to local conditions. In addition, many of the practices and policies
described here provide examples of solutions that other cities have enacted to
address land-use conflicts related to the urban forest.N
o
.
4
60
The authors selected city ordinance and planning documents
based on both environmental and political factors. Climate was
a key component used to evaluate ecological criteria, along with
stormwater and air pollution impacts.
Sacramento, California shares two essential characteristics with
Salt Lake City; both are state capitols and receive similar annual
precipitation volumes. Both cities have an area of approximately
100 square miles, although Sacramento has 2.5 times the
number of residents. The findings and purpose of Sacramento’s
tree planting and conservation ordinance (Chapter 12.56) of
Sacramento’s ordinance foreground the role of trees in public
and environmental health:
The city council finds that trees are a signature of the City
and are an important element in promoting the well-being
of the citizens of Sacramento...When proper arboricultural
practices are applied, trees enhance the natural scenic
beauty of the City; increase oxygen levels; promote
ecological balance; provide natural ventilation and air
filtration; provide temperature and erosion controls;
increase property values; and improve the quality of life.
The city council also finds and determines that it is in the
public interest to protect and manage tree resources
within the City to preserve and maintain the benefits they
provide to the community.
Minneapolis, Minnesota, is also known for its thriving, robust
urban forests. The first line of the Minneapolis 2016 revision to
its urban forestry policy states: “The urban forest is an integral
part of the Minneapolis infrastructure” (Board, 2016). In this
way, the City makes clear that the urban forest will be planned
and managed on par with other types of city infrastructure.
While ordinance and public policy are critical to the urban forest,
departmental policies and guidance play an equally central role.
As the American Public Works Association Notes:
The adoption and enforcement of urban forest
management policies and guidelines can support
a change ... from a problem-specific, crisis
management, and reactive approach to a more
proactive, professional management response. The
lack of such useful policy statements and guidelines can
allow agencies to act independently without regard to
efficiency or effectiveness, hinder attempts to coordinate
the action of public agencies regarding the proper
management of public trees, and can confuse interaction
of the public works agency with citizens, businesses,
utilities, and other outside entities when dealing with
public trees (APWA, n.d.)
URBAN FOREST OVERSIGHT
Portland, Oregon, has an 11-member Urban Forestry Commission,
whose members are appointed to 4-year terms by the mayor in
consultation with the Parks and Recreation Commissioner and
approved by City Council.
At least three commission members “have experience and
expertise in arboriculture, landscape architecture or urban
forestry.” The remaining seven members represent a wide range
of neighborhoods. There is also an Urban Forestry Appeals Board
which hears appeals related to the City Code provisions for the
Trees and Urban Forestry (Title 11).
The Portland Urban Forestry Commission meets at least ten
times annually, and its’ responsibilities include:
1. Assisting with the development, reviews, and updates
to the urban forest plan.
2. Providing review and input on plans, policies, and
implementation projects that affect urban forestry.
3. Advising the City Forester, Parks and Recreation
Commissioner, and the Citizen’s Budget Advisory
Committee on annual Forestry Division budget requests.
4. Making recommendations to the city council relating to
amendments to the Urban Forestry Program, the urban
forestry Code, heritage tree nominations, and other City
department budget requests that substantially affect urban
forest programming.
Policy
Best practices were selected from urban areas identified in a U.S.
Forest Service-funded study of the ten best urban forests in the
United States. The most significant commonalities in these ten cities
were sustained investment in urban forest health, partnerships with
nonprofit organizations, and community participation.
In alphabetical order, the best municipal forests in the United
States, according to a 2013 American Forests assessment are:
• Austin, TX
• Charlotte, NC
• Denver, CO
• Milwaukee, WI
• Minneapolis, MN
• New York, NY
• Portland, OR
• Sacramento, CA
• Seattle, WA, and
• Washington, D.C.
For specific issues related to Urban Heat Island Effect mitigation,
the Planning Division reviews best practices from cities in the
United States desert southwest.
61
URBAN FOREST PLANNING
According to the Vibrant Cities Lab, the best urban forest master
(or management) plans address multiple subjects and priorities
to manage and sustain the urban forest. In particular:
• Planting strategies for public sites that deliver benefits to
neighborhoods where needed;
• Policies and incentives that promote tree preservation and
planting on private lands;
• Systematic monitoring;
• Regular, scheduled maintenance;
• Pro-active risk assessment and management;
• Long-term funding and staffing;
• Active support from municipal agencies,
volunteers, nonprofits; and
• Disaster response, mitigation, and remediation.
(USFS et al., n.d.)
The American Public Works Association series on Urban
Forestry Best Management Practices (BMPs) for Public Works
Managers notes the importance of creating an Urban Forest
Management Plan, stating:
The existence of an urban forest management plan
in a community indicates a high level of commitment
to protecting trees, and it indicates a higher level of
education and knowledge about natural resource
PLANNING THE URBAN FOREST
The American Planning Association recommends that planners collaborate with urban foresters to create:
• Requirements for detailing tree-planting plans in site plan submissions.
• Regulations regarding tree preservation procedures in the development process.
• Management guidelines for tree issues arising in the public hearing process on proposed developments.
• Review of site plans, including having an arborist check the plans for compliance on tree-related issues.
• Requirements for tree-planting and tree-preservation requirements in subdivision regulations.
• Development and enforcement of standards for tree planting and maintenance in parking lots.
• Monitoring of tree protection and proper planting during site development. (APA, 2009)
5. Preparing an annual report that addresses relationships
with and City Forester concerns with other city departments.
The report includes “an evaluation of the opportunities and
barriers to effective management of the urban forest, and
assessment of progress on these issues identified in prior
annual reports.” (City of Portland, Oregon, 2021)
issues in general. The benefits of trees can be
maximized when both professional management
resources and an educated public coexist.
With a tree inventory and urban forest management
plan, a public works agency can objectively consider
each specific issue and balance these pressures with a
knowledgeable understanding of trees and their needs.
(APWA, n.d.)
Urban forest planning (along with other types of green
infrastructure) should collaborate between municipalities and
counties within a single ecosystem boundary to maximize
urban forest benefits, particularly improvements to water quality.
Watershed-level tree canopy goals, for example, can be set
through regional councils to improve water quality (APA, 2009).
PERFORMANCE METRICS
Urban forest plans should include metrics developed to assess
whether or not the urban forest is performing effectively to
achieve a targeted outcome. Performance outcomes of the
urban forest can consist of many different criteria, such as
the “amount of carbon sequestered, localized temperature
improvements, reductions in the number of bike accidents,” and
increased stormwater storage capacity during peak precipitation
events. (Canfield J., 2018)
Assessing performance and creating targets can provide data to
guide decision-making on future projects and produce findings
that demonstrate the urban forest’s return on investment (ROI).
Sharing this data with partner agencies and the public can
effectively justify consistent expenditures for tree stewardship
(see Funding, below, for additional details).
62
EQUITY IN THE URBAN FOREST
Urban forestry programs in the United States tend to be most
effective in more affluent areas, creating inequities in urban
forest distribution and its’ associated benefits. The most
successful programs to implement equity in the urban forest
employ policies and practices that:
• Develop strong partnerships between municipalities
and nonprofits;
• Reduce the responsibility of residents for City-owned trees;
• Focus planning in smaller, highly targeted areas; and
• Use publicly owned property whenever feasible.
(Vibrant Cities Lab, n.d.)
Research on equity outcomes in cities with high-performing
urban forests demonstrates that highly integrated partnerships
have the best results. When municipalities supply funding,
technical assistance, and labor, and partner nonprofits are
deeply embedded in cities and provide volunteers, outreach,
and education, equitable distribution of public trees is more likely
to be achieved. (Ketcham, 2015)
Cities in arid regions have had success planting drought-
resistant, heat-tolerant tree varieties in financially stressed
areas. In Tucson, Arizona, the Sonora Environmental Research
Institute piloted a grant-funded project with a local nonprofit,
Trees for Tucson, to increase canopy cover in low-income
areas. The Pima Association of Governments identified South
Metropolitan Tucson as having significantly fewer parks and
vegetation, and the area received new plantings. Working
with promotoras (community health workers) and volunteers,
the researchers conducted extensive community outreach to
enroll residents and distribute both trees and tree stewardship
information in English and Spanish to area residents, including
tree care classes. (Foley, 2019)
Equity also requires a more significant investment in the urban
forest on the part of municipalities. A recent cost assessment
of the urban forest in Portland, OR, found that the City needed
to make a more considerable investment to ensure equity. The
consultant team, Davey Resource Group, noted that the City
needed to make “an investment in a programmatic shift of tree
care responsibilities. With the unequal distribution of trees and
burdens for the costs of tree care left to property owners, the
City will be challenged to improve the condition of its street tree
populations in lower-income, and lower canopy neighborhoods.”
(City of Portland, Oregon Parks and Recreation, 2019)
ENVIRONMENTAL IMPACT MITIGATION
Robust urban forest policy and planning should include
quantifiable strategies to mitigate negative environmental
impacts and associated adverse public health outcomes. (Urban
forest planning should also provide approaches to reduce
the negative social implications of poor urban design, see
Placemaking, below, for detail).
Planting broadleaf trees on the east side of streets to shade
buildings can reduce air conditioning costs significantly.
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AIR QUALITY IMPROVEMENT
Air quality mitigation measures need to be calibrated to specific
pollutants of concern and balanced with needs to reduce energy
consumption, manage stormwater, and provide a safe, walkable
urban realm. In the broadest sense, this means “planting the right
tree in the right place,” and following up with testing and analysis
to measure outcomes.
According to the US Forest Service, some recommended
urban forest management strategies to improve air
quality include:
• Sustain the existing tree cover and increase the number
of healthy trees,
• Use low biogenic volatile organic compound (BVOC)
emitting trees to reduce ozone and CO2 formation,
• Use long-lived trees to reduce long-term emissions from
planting and removing cycle,
• Reduce fossil fuel use in vegetation maintenance,
• Plant trees in energy-conserving locations,
• Plant trees to shade parked cars to reduce vehicle
VOC emissions,
• Supply ample water for tree growth - fosters pollution
removal and temperature reduction,
• Plant trees in polluted or heavily populated areas, and
• Avoid pollutant-sensitive species. (Nowak, 2002)
Some evergreen trees can remove particulates year-round when
planted strategically as buffers in locations with high particulate
matter concentrations. However, due to safety issues caused
by reduced visibility, evergreens generally are not appropriate
street trees. Further, typical evergreens do not produce
adequate canopy to achieve comfortably shaded sidewalks.
Evergreens can provide too much shade to sidewalks in winter,
preventing sunlight from reaching sidewalks, and resulting in loss
of human comfort and potentially icy (slippery) conditions. Cities
should consider evergreens for strategic planting on public or
private property bordering freeways (or other high-emissions
traffic routes), provided that safety concerns are addressed.
ENERGY CONSERVATION
Planting deciduous trees to shade windows can provide
significant reductions in energy use. “In a study of the impacts
of street trees in California, Lawrence Berkeley National
Laboratory and Sacramento Municipal Utility District found
that trees placed around houses to shade windows yielded
between 7 and 47% energy savings. Other studies suggest
energy savings from properly planted trees may be closer to
5–10%.” (American Rivers et al., 2012)
Trees Charlotte, a North Carolina public/nonprofit partnership,
recommends planting deciduous trees on residential buildings’
southern and western facades. Strategically locating trees
reduces air conditioning use in summer and decreases the need
for heating in winter via passive solar gain. “Strategically placed
shade trees – a minimum of three large trees around [a] home –
can reduce air conditioning costs up to 30 percent.” Evergreen
trees, when correctly located, can block winter winds and reduce
energy consumption for heating between 10 and 50 percent.
(Trees Charlotte, 2015).
64
WATER QUALITY + STORMWATER
MANAGEMENT
Like Salt Lake City, Boise is a Mountain West capitol, the largest
city in the state, and has a similar climate. Boise experiences
air pollution associated with winter temperature inversions and
often has high summer ozone levels. Although it receives less
annual precipitation than Salt Lake, Boise has made the urban
forest the centerpiece of its stormwater management strategy.
Boise’s 2015 Urban Forest Management Plan incorporates water
quality and stormwater management goals by increasing canopy
cover to intercept rainfall and subsurface stormwater retention
and infiltration. The plan prescribes large trees to achieve a 15%
increase in canopy cover from existing conditions.
Large trees require a greater soil volume, which can be
challenging to achieve in highly paved areas. Boise used
suspended pavement systems downtown to address this
problem, supporting large trees and creating underground areas
for root mass and stormwater retention and infiltration. (Vibrant
Cities Lab, 2015)
(See Suspended Pavement Systems, below, for more information.)
URBAN HEAT ISLAND
In the desert Southwest, metropolitan governments have
expanded their urban forests to address the interconnected
issues of livability and equity in their cities. One of the guiding
principles of Tempe, Arizona’s 2017 Urban Forest Master
Plan is “Expand Shade to Maximize Urban Cooling.” Shade is
the central strategy for Tempe’s 2040 General Plan Goal of
becoming a “20-Minute City.” In this type of city, all services
and amenities are accessible to residents within a 20-minute
walk, bike ride, or transit ride from their neighborhood. The
Urban Forest Master Plan directs the City of Tempe to: “Create
a vibrant, walkable 20-Minute City that benefits public health
and economic development by planting trees and building
structured shade. Designers can augment this principle by
planting trees [on private property] and using construction
materials that reduce the urban heat island (UHI) effect.” (ASU
Sustainability Solutions Initiatives, 2017).
Tempe’s big-city neighbor, Phoenix, developed a Tree and
Shade Master Plan in 2010, demonstrating the critical importance
of providing shade in arid, sunny urban climates. The plan
examined regulatory hurdles preventing shade structures over
public sidewalks to quickly add shade to pedestrian routes and
outlined strategies to increase the tree canopy. The vision set
forth is for shade canopy coverage over 25% of the City in the
two decades between 2010 and 2030. (Phoenix, 2010)
The City of Phoenix’s Zoning Ordinance’s general landscaping
standards (Chapter 13, Walkable Urban Code - Section 1309.A)
requires street trees to be planted in the public right-of-way,
with exceptions for public utility easements. When projects
cannot include trees, they must use architecturally or artistically
integrated public amenities to provide shade. Public amenities
can include structural shade, seating, artwork, and wayfinding
signage. See Transitional Elements, below, for more detail and
examples of public amenities used to provide shade.
The Downtown Code includes shade standards, which require
that building orientation minimize heat gain and consider the
impact of shade on adjacent areas. Buildings over 5,000 square
feet or building additions of over 500 square feet are required
to provide shade over 75% of the public sidewalk, 50% of
which must be provided by trees or trellised vines. The shade
calculation is based on the summer solstice and may include
shade cast from a building. (Phoenix, Zoning Ordinance, n.d.)
65
The American Planning Association (APA) advocates a
balanced approach to preservation and development. The
APA recommends ordinances recognizing which trees require
protection and reasonably account for all the benefits trees
provide when removing healthy trees.
The best tree preservation ordinances recognize that it
is unnecessary to preserve all trees to allow for desired
types of development. These ordinances place significant
trees in the site design and review process.
…When trees are destroyed during development, a
good tree preservation ordinance provides methods for
quantifying the value of the lost benefits provided by
those trees and creates a mechanism for that value to be
returned to the community (APA, 2009).
The (APA) recommends that to preserve trees and maximize
the urban forest’s performance; municipalities should:
1. Integrate tree protection and planting requirements into
the zoning ordinance and not rely on a separate tree or
urban forestry ordinance;
2. Foster collaboration between planners,
interdisciplinary city-staff, decision-makers, developers,
environmental advocates, and other community
stakeholders to draft ordinances;
3. Develop performance standards for Planned Development
approvals; and
4. Create clear, realistic means to enforce tree preservation
regulations with a process driven by internal city
department collaboration. (APA, 2009)
Preservation
URBAN ECOSYSTEM HEALTH
The urban forest should be considered holistically in terms of
its relationship to built systems and other parts of the urban
ecosystem, including waterways, wildlife, and social spaces.
MINIMUM SOIL VOLUME ORDINANCE
Adequate soil volume is critical to the size, health, and longevity
of urban trees. Although some cities regulate planting space
with surface area, many cities now require minimum soil volumes
by ordinance, guidelines, or streetscape specifications. These
cities include Boise, Denver, San Diego, Seattle, Chicago, New
York, and the state of Minnesota requires minimum soil volumes.
(Marritz L., 2020).
In areas with extensive pavement, such as downtowns, cities
increasingly use suspended pavement systems to maximize
growing conditions and comply with required soil volumes. (See
Suspended Pavement Systems below for more information and
examples of this technology).
ROOT PRESERVATION ZONE
The Arborist for the City of Austin, Texas, notes that “Tree
preservation is effectively defined as root system preservation,”
and assigns a “Critical Root Zone (CRZ) Area “to each tree based
on the diameter of its trunk. Austin requires that 50% of the CRZ
remain undisturbed to ensure minimum compliance with its
Environmental Criteria Manual (3.5.2 – Tree Preservation Criteria),
adopted as part of its city code. (City of Austin, Texas, 2020).
City of Austin Tree Preservation Guidance
http://austintexas.gov/page/tree-and-natural-area-preservation
66
LEAF LITTER REMOVAL +
WATER QUALITY
City land managers can mitigate the impacts of urban forest leaf
litter on water quality (described in Chapter 2) through various
means, the most common practice being street cleaning paired
with robust leaf litter removal programs. (Selbig, 2016)
Sacramento designates a “leaf season,” between November
and January, when people are allowed to rake leaves into the
street, along the curb, in addition to using yard waste bins.
During leaf season, Sacramento’s Recycling and Solid Waste
division have “10 to 15 crews using ‘The Claw’ and rear loader
trucks to scoop over 26 million pounds of leaves and yard waste
debris off of city streets. Crews work up to six days a week, rain
or shine, including holidays.” (City of Sacramento, 2017). During
leaf season, the Recycling and Waste Division will collect up
to 13 containers of leaves from houses. Each street gets a visit
from “the claw” 7 times to collect curbside leaf litter. (City of
Sacramento Public Works, 2020)
Minneapolis does not permit leaves to be swept into the street
and requires yard waste to be bagged or bundled. In addition to
yard waste bins, the City allows residents to use kraft paper bags
and BPI-certified compostable plastic bags. Conventional plastic
bags are prohibited for yard waste. (Minneapolis, MN, n.d.)
The City of Boise uses a combination of yard waste bins and
large paper bags for leaf litter collected through its unlimited
compost program. Boise then composts the material and provides
the finished product to residents for free. (City of Boise, n.d.)
Denver’s street sweeping program has a monthly schedule. It
enforces posted parking restrictions so that both sides of the
street are cleaned. Denver’s Department of Transportation and
Infrastructure (DOTI) notes: “Street sweeping plays a critical role
in keeping Denver’s streets, air and water clean. DOTI’s street
sweeping program removes dirt, leaves and debris from city
streets, which reduces air and water pollution and supports a
clean environment.” (Denver, 2020)
INCENTIVES
Many cities provide incentives to developers to enhance
and protect the urban forest or provide other types of green
infrastructure. These include:
• Density bonuses;
• Flexible development standards;
• Reduced development fees;
• Streamlined approval processes; and
• Permit fast-tracking.
The APA notes that “In practice, localities often provide these
incentives to projects that qualify for specific green building or
neighborhood certifications.” (American Planning Association
Green Communities Center, 2016)
ENFORCEMENT
Many municipalities use tree Protection (or Preservation)
Bonds throughout the United States to protect trees during
construction activities.
According to Alpha Surety and Insurance Brokerage,
A Tree Preservation Surety Bond is a license. It permits
surety bond required by certain jurisdictions for
individual and commercial property developers. The
bond typically ensures one of two things. It guarantees
that the construction project will not harm specific
trees considered to be protected, and, if damaged, the
developer will reimburse the jurisdiction for [its] loss. Two,
it guarantees that the developer will plant replacement
trees for protected trees that they must tear down for the
construction project. Once the project is complete and
the jurisdiction verifies protected trees are unharmed and
[healthy] replacement trees are in place, a municipality
can release the bond.
Bonds are often held for two to three years after a Certificate
of Occupancy is issued. This time span gives new trees time to
establish and incentivize the developer to water and care for
the plantings.
Fines assessed for violations of Tree-related ordinances can
be relatively high in some cities. In Sacramento, for example,
breaches of the Tree Planting, Maintenance and Conservation
Code incur civil penalties between $ 250 and $ 25,000 per day.
(City of Sacramento)
Case studies demonstrate that cities are most effective in
protecting the urban forest when they take a collaborative,
interdisciplinary approach between departments to creating and
enforcing ordinances. (APA, 2009)
Another preservation incentive that many cities provide is a
Tree Memorial program, which can also serve as a funding
source for urban forestry programs. Boise, for example,
runs a Tree and Bench adoption program which focuses
on resources in City parks. The adoptions have a 20-year
term, are renewable for a second 20-year term, and can
commemorate people, dates, and events.
A personalized plaque (designed using City standards) is attached
to a tree or bench in either a neighborhood or “premiere” park.
Plaque pricing is based on location, tree size, or bench material.
Eligible trees must be at least two years old, ensuring that the tree
will thrive for the adoption period. (City of Boise, 2020)
By associating a tree with a person or event, it becomes imbued
with cultural and personal meaning. It is, therefore, more likely to
be quickly understood as an essential resource and preserved.
67
SOLUTIONS FOR UTILITY +
TREE CONFLICTS
Conflicts between trees and utilities (both above and below
ground) are commonplace in municipalities. There are various
ways to either avoid or mitigate conflict. First, avoiding conflict
by proactive planning for utility and tree placement during the
project design phase. Proactive approaches ensure trees are
located and sized appropriately and are generally the most cost-
effective approach; this is common practice for above-ground
utilities. However, avoiding utility conflict is not always possible
for below-ground utilities, particularly with urban infill projects.
Cities can develop a geographic information system (GIS)
analysis of utility locations to model the outcome of their current
policies to determine if canopy or tree stocking goals can be met
using those criteria.
For example, Salt Lake City’s current policy is that trees must be
located at least 10 feet from existing or proposed water lines.
The city also requires street trees to be planted (or replaced) at
approximately every 30 feet based on zoning code requirements
related to building frontage.
TREE REPLACEMENT MITIGATION
According to arborist Dr. R.J. Laverne, Manager of Education
and Training for Davey Tree, the best approaches to tree
replacement costs factor ecosystem services and public health
benefits into their fees. He notes:
An inventory of the trees lost during construction can be
used to calculate a monetary value that fairly represents
the lost benefits to the community. Cities can then
require the developer to pay the “lost benefit” sum
into a community fund to plant and maintain trees. It is
necessary to develop a method that fairly translates the
environmental, social, and economic value of trees into a
dollar amount. (APA, 2009)
Sacramento requires that private protected trees and all
public trees be replaced either on or off-site. Fees in lieu of
replacement are only permitted through a resolution adopted
by City Council. Those fees and civil penalties for violations are
deposited into a Tree Planting and Replacement Fund, which can
only be used for that purpose. (City of Sacramento)
Some municipalities use a different approach when
developers cannot provide the required number of trees on
private property to establish an off-site mitigation bank. In
Fulton County, Georgia, these are referred to as “tree banks,”
and defined as “a site such as a school or public park, where
the owner/developer shall donate and plant the required
trees when it is not feasible to plant the required trees within
their site’s project area.” (Fulton County, 2020)
By spatially locating both on a map, areas of conflict become
evident. These areas can then be overlaid with maps of
proposed projects or city code amendments, along with priority
areas for tree preservation and expanded planting.
In high-priority tree planting locations where utility conflicts are
unavoidable, there are a variety of technologies and techniques
to either resolve disputes or mitigate potential problems. These
costs should be factored into project planning in locations where
tree planting or preservation is highly prioritized. Additionally,
city land managers can further analyze utility lines scheduled
for abandonment to plan for trees in those locations on the
appropriate timeline.
MITIGATION TECHNIQUES
Mitigation measures for underground utilities include a range
of actions and technologies:
1. Locate utilities in a designated utility corridor that will not
conflict with tree roots.
2. Place utility lines in the street instead of the park strip
(particularly as opportunities become available during road
reconstruction projects).
3. If cities must locate utilities in park strips (without existing
trees, they should place utilities directly behind the curb
and not in the center of the park strip, where trees are
typically planted.
4. Place conduit that resists tree-roots during new
construction to accommodate current and future proposals
for utility lines as technologies change.
5. Plant trees with non-invasive roots or trees with a
small root ball.
6. Use physical or (non-toxic) chemical barriers near utility
lines to inhibit root growth. (Teske, 2013)
7. Combine utilities by using suspended pavement systems
for stormwater management and planting trees. (In
locations with clayey subsoils, an underdrain for overflow
stormwater can be placed below the tree root zone).
8. Consolidate utilities and stack them vertically in one
predictable location (City & County of San Francisco, 2015).
9. Place utilities in precast concrete vaults underground.
68
SUSPENDED PAVEMENT SYSTEMS
In densely paved urban areas where soils are typically heavily
compacted, suspended pavement systems have become a go-to
solution to providing soil volumes that support healthy, large trees.
Suspended pavement systems, often referred to by the brand
name Silva Cell, support pavement loads while creating space
for tree roots without soil compaction. These systems also store
overflow stormwater, which eventually waters the tree and
infiltrates into the soil, recharging groundwater supplies and
improving water quality.
A 10-year study in a commercial area in Toronto demonstrated
that supported pavements systems:
• Increased the tree canopy while using a small surface area;
• Provided stormwater management through reduced
water volumes;
• Improved water quality through increased infiltration and
pollutant removal by soil; and
• Promoted Low-Impact Development (LID), or Green
Infrastructure, without the higher maintenance costs incurred
by surface bioretention swales. (Sustainable Technologies
Evaluation Program (STEP), 2018)
A 2006 study that compared structural soils, non-compacted soils,
and suspended pavement systems found that
“Suspended pavement over non-compacted soils
provided the greatest amount of tree growth and health
and should be considered when designing urban planting
sites for trees.”
Trees in suspended pavement systems were also “larger, faster-
growing, had better color, and more root growth.” (Smiley, 2006)
Silva Cell™ System
(Ecological Engineering, Vol. 82, September 2015).
Suspended pavement systems allow roots to thrive, growing large, healthy trees, while also storing overflow stormwater.
Photo above shows a Silva Cell™ System being installed in Toronto, Canada 2010 (Deeproot.com)
69
FUNDING
Urban forestry programs require stable, adequate funding
sources to maintain the benefits trees provide throughout their
lifespan. The American Planning Association notes that urban
forestry programs are most often underfunded based “on
perceptions of its benefits to the community,” which are usually
only considered in terms of aesthetics. One of the best ways
to ensure stable funding is to document the multiple benefits
of the urban forest over the long term and ensure that those
benefits are regularly and effectively communicated to the
public. (APA, 2009)
In the past urban forests were viewed as expensive aesthetic
benefits, in which individual trees were relatively disposable
resources. Now, however, municipalities are increasingly
quantifying the value of the ecosystem, public health, and social
benefits urban forests provide, as well as their contribution
to economic development. The urban forest becomes a
profit center by viewing the urban forest as infrastructure that
generates follow-on economic benefit (in the same manner as
roads, light rail, and other infrastructure).
While general fund allocations are typically the primary funding
source for urban forestry programs, there are other possibilities
for consistent funding streams dedicated to the expansion and
preservation of the urban forest. For example:
• Olympia, Washington uses a capital improvement plan fund
derived from real estate excise taxes and utility taxes, with
interest, to underwrite its program.
• Salem, Oregon funds its care of street trees through the
municipal portion of the state motor fuel tax while funding
some tree preservation through fines and donations.
• Urbana, Illinois, also uses fines to aid its program, particularly
for motorists who damage trees in crashes.
• Other cities have carved out a role for nonprofit organizations
in supplementing tree funding. For example, the Sacramento
Tree Foundation is substantially funded by the local Municipal
Utility District. (APA, 2009)
Partnerships between cities, chambers of commerce, and
philanthropists are another route to generate funds for urban
forest expansion and maintenance. Denver, Colorado, has
created an Urban Forest Initiative to grow the downtown area’s
urban forest canopy from 4% to 10% cover. The Initiative is jointly
funded by the Downtown Denver Partnership, City and County
of Denver, Downtown Denver Business Improvement District,
property owners, and the philanthropic community. It provides
grants to property owners to improve tree-growing conditions.
Promotion
Another method to provide funding for the expansion and
ongoing maintenance of urban forests is creating Community
Benefit Districts or CBDs (known as Business Improvement
Districts in Salt Lake City). Cities can create these districts in
commercial areas and mixed-use neighborhoods, developing a
public/nonprofit partnership to supplement existing public funds
used to maintain and improve those areas. Communities vote
to establish CBDs, and then “local property owners are levied a
special assessment to fund improvements [and maintenance in]
their neighborhoods. The funds are administered by a nonprofit
organization established by the neighborhood.” (City and County
of San Francisco, n.d.)
70
INVESTING IN THE URBAN FOREST
IS INVESTING IN PUBLIC HEALTH
A 2016 Nature Conservancy white paper, Planting Healthy
Air, found that street trees are a cost-competitive solution to
reducing concentrations of particulate matter (PM) as well as
lowering temperatures.
The benefits that trees deliver, in terms of $ per ton of
PM removed or $ per degree of temperature mitigation,
are in the same range as major built infrastructure
alternatives. More importantly, street trees are able to
deliver benefits both to PM and temperature mitigation,
while grey infrastructure alternatives generally are not.
(McDonald, 2016)
The return on investment is greatest when neighborhoods with
the highest residential density are targeted for tree planting. For
example, in Los Angeles, researchers found that by investing an
additional $6.4 million annually in street tree planting in central
LA, Santa Monica, and Long Beach, an estimated 400,000
residents could experience a reduction of 2.7° F (1.5°C) in
summertime temperatures. (McDonald, 2016)
Investigating cities across the globe, the Nature Conservancy
found that approximately $4 per city resident spent on urban
forests can significantly mitigate air pollution and provide
urban cooling.
COMMUNICATION
Communication and education about the urban forest and its
benefits is a crucial aspect of gaining public participation in the
stewardship work. Information about the Urban Forest’s value to
multiple parts of community building should be disseminated to
all City departments, plan reviewers, developers, and Salt Lake
City residents.
The Salt Lake City-based nonprofit TreeUtah incorporates
education into every aspect of its work. Volunteers run
workshops, guided tree identification hikes, and provides
curriculum to second-grade students through their Discovering
Trees program. The organization has approximately 30 team
leaders and would like to increase the volunteer group to 50.
Volunteers range from one-day participants to team leaders
and professional arborists. TreeUtah plans to expand its online
presence by recording online workshops, live streaming in-
person events, and educating the public through social media
storytelling to reach a broader and more diverse audience.
(Personal Communication, May, 2021)
The Sacramento Tree Foundation (SacTree) plays a significant
role in the success of the City’s urban forest. Pamela Frickmann
Sanchez, the Education Programs Manager for the Sacramento
Tree Foundation, attributes the organization’s success to forming
partnerships with utility companies, which has allowed them to
expand their educational outreach efforts. The organization works
closely with Sacramento Municipal Utility District (SMUD), a publicly
owned utility company, and Sacramento’s water company.
The water company uses its platform to invite residents to classes
on tree irrigation and tree care conducted by SacTree. The
ongoing partnership and SMUD funding allow SacTree to provide
professional consultations to property owners who receive free
shade trees through the Sacramento Shade program. SacTree
assists the owners in picking out an appropriate tree, delivers the
trees, and plants them. Working with the utility companies ensures
the trees are planted in proper locations and do not conflict
with existing or planned infrastructure, provides a free service
to residents, and promotes the mission of the Sacramento Tree
Foundation. (Sanchez, 2021)
Cities can also use graphic design, social media, and place-
based campaigns to communicate the benefits of and threats
to the urban forest. For example, The City of Denver uses a
tongue-in-cheek marketing campaign (below) to educate its
residents about the danger of Emerald Ash Borer, an invasive
pest introduced in 2002 which has decimated millions of
Ash trees, primarily east of the Mississippi River. (Ash is a
widespread species for street trees and timber use whose
presence was first detected in Colorado in 2013).
URBAN FOREST + ECONOMIC
DEVELOPMENT: ADDED VALUE
A healthy urban forest adds value to both retail and residential
development in cities of all sizes, as demonstrated by
numerous studies and surveys (for additional information,
see the University of Washington’s website on the Human
Dimensions of Urban Forestry).
A combination of user-friendly regulations and effective
communication of added value to developers, investors, and
nonprofits is key to creating the partnerships needed to sustain a
thriving urban forest.
71
Retaining trees during development can be an effective way for
developers to increase profit margins. As multiple studies cited
on the Green Cities: Good Health website demonstrate:
“Understanding potential market values in different
forest conditions is an important step in understanding
the economics of urban forest protection. Market price
studies of treed versus untreed lots show a range of
value enhancements:
Generally, trees and forest cover in development
growth areas add value to parcels. One study found that
development costs were 5.5% greater for lots where
trees were conserved. Given increased lot and home
valuations, builders have reported that they were able
to recover the extra costs of preserving trees through
a higher sales price for a house, and that homes on
wooded lots sell sooner than homes on unwooded lots.”
Communicating this to decision-makers and developers
can assist both in the ordinance amendment process and
demonstrate that existing trees are often an asset to the
development and should be managed and protected.
The City of Boise aims to become “the most livable city in the
country.” It has made street trees a centerpiece of their LIV
district strategy (LIV is an acronym for Lasting environments,
Innovative enterprises, and Vibrant communities).
Boise’s central addition LIV district, a 50-acre area downtown,
used a combination of pervious paving and Silva Cells™ (see
Suspended Pavement Systems, above, for details) for stormwater
management as a strategy to attract development by adding
amenity (large trees) and increasing developable land area.
Boise requires private property owners to manage all stormwater
volumes from 50- or 100-year storms on-site, while the Ada
County Highway District manages stormwater runoff from
rights-of-way and public streets in Boise. Stormwater is typically
infiltrated into soils due to local soil characteristics and low
annual precipitation levels.
The Urban Land Institute (ULI) interviewed Boise’s
stormwater program coordinator, Steven Hubble, about
the economic benefits of using suspended pavement in
the right-of-way.
He noted:
“In the Central Addition, we adopted the idea of
using space in the public right-of-way for stormwater
management both for [City] and private property, given
that there would be a benefit to the public by treating
the roadway runoff and allowing an opportunity for
private development to focus their stormwater in those
areas. [This allows] an easier pathway to more vertical
development on those sites.” (Urban Land Institute, 2018)
ULI’s recent assessment of the impact of rising temperatures
and heatwaves on urban development examines the growing
risk posed by extreme heat. The authors note that “Widespread
adoption of mitigation strategies could help reduce the urban
warming trends currently occurring in cities, leaving them
to contend with a more manageable 1-degree to 2- degree
Fahrenheit increase, rather than the 5-degree to 10-degree
increase currently projected for some cities due to the urban
heat island effect.” (Burgess, 2019)
The report explores a range of heat mitigation practices,
including providing additional shade through canopy, and note
the significant return on investment, including:
• Improved tenant experience,
• Reduced operating costs,
• Enhanced likelihood of business continuity,
• Enhanced branding, and
• Additional foot traffic in pedestrian and retail environments.
In addition, ULI notes that
Being “heat-resilient” can reduce the likelihood of
construction delays caused by extreme heat, increase
support from investors, public officials, and other
stakeholders, and reduce stress on public infrastructure.
…Heat resilient projects can reinforce the developer’s
reputation for high-quality, green design; and they can
become heavily patronized places of refuge during
extreme-heat events, leading to enhanced asset value,
higher rent premiums and lower vacancy rates.
...Operating costs can decline due to less frequent
replacement of heat-damaged materials, lower utility
costs, and higher chance of sustained operations during
extreme heat events. (Burgess, 2019)
Price Increase Condition
18%Building lots with substantial
mature tree cover
22%Tree-covered undeveloped
acreage
19-35%Lots bordering suburban wooded
preserves
37%Open land that is two-thirds
wooded
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PUBLIC/NONPROFIT PARTNERSHIPS
Our City Forest, a San Jose, California nonprofit urban forestry
and environmental stewardship organization, works closely
with the municipality to provide native and drought-tolerant
trees, shrubs, and grasses at wholesale pricing. Our City Forest
runs a community nursery and training center where certified
arborists and tree experts assist residents in choosing the right
tree for their property and obtain a planting permit from the
City if the tree is to be planted in the park strip. The nonprofit
also has an award-winning partnership with AmeriCorps, where
service members are trained to be urban forestry and outreach
specialists who go into the broader community to educate
residents on best practices.
The Sugar House Park Authority, a local nonprofit, has a
successful 50-year partnership with Salt Lake City and County.
The Park Authority was deeded the park property, in trust, from
Salt Lake City and Salt Lake County after Utah relocated its State
Prison in the 1950s. The Board of Trustees consists of seven
volunteers and one representative from Salt Lake City and Salt
Lake County agencies.
The Park Authority has a 99-year lease to own, maintain, and
operate the park with funding provided by the government.
(Authority, n.d.) TreeUtah partners with the Park Authority to
plant trees as a part of their Commemorative and Memorial Tree
Program. The Park Authority maintains a list of preferred trees,
and residents work with TreeUtah to select and plant the tree in
memory of a loved one.
Vancouver, British Columbia, has a popular and successful Green
Streets program where residents volunteer to maintain small
gardens in traffic circles, medians, and other small plots created
for traffic calming in neighborhood rights-of-way. The City
provides the capital investment, and all maintenance, including
pruning and weeding, is performed by the volunteers.
PARTNERSHIPS FOR FOOD ACCESS +
URBAN AGRICULTURE
Urban forests can be a source of fresh, accessible produce and
an opportunity for education on food and nutrition. Incorporating
collections of food-bearing trees, either as a supplement to
landscaping in parks and playgrounds, as street trees, or in an
orchard format (commonly called a food forest), can be an added
layer of long-term support for communities.
Another aspect of urban forestry programming that can support
food access is providing shade on sidewalks and bike lanes.
Shaded pathways for short trips to grocery stores and farmers’
markets are more comfortable and inviting, particularly in low-
income neighborhoods.
Currently, most fruit tree programming in cities across the United
States (including Salt Lake) is through the collection of fruit on
private property. Independent nonprofits typically manage fruit
harvests with some support from the municipal government,
such as the local Green Urban Lunch Box . In Salt Lake City,
Green Urban Lunchbox volunteers also pick fruit from trees on
government properties.
Municipal fruit trees and edible landscapes are predominantly
located in city parks or small, publicly accessible orchards. These
are often managed via partnerships with community garden
organizations. The City of Durham, North Carolina, has a 5-acre
City-owned park in their downtown that a nonprofit organization
entirely operates. The park has an edible public garden that
grows publicly accessible fruit trees along with other edible
plants. While a 501c3 organization manages Durham Central
Park, the City of Durham and other partners provide funding
support. (Durham Central Park, 2013). Programs like this allow
for long-term funding support and management while including
public partners with a broad community reach.
Additionally, it is vital to have an appropriate policy supporting
the public use of these trees, as exemplified by Minneapolis’
recent ordinance change to allow the foraging of fruits in most
public spaces (Minneapolis Parks, 2018). Alternatively, some
cities have taken on most of the funding and management
of planting fruit trees and other food plants in public spaces
throughout the City (Vicenti, 2020). Copenhagen is implementing
municipal fruit trees and shrubs in parks, playgrounds, sports
fields, and churchyards throughout the City (Geddo, 2019).
The key to having fruit trees become an integrated and utilized
part of the community is making information available both
digitally and on-site for education purposes and creating
opportunities for communities to engage with the trees.
Workshops, cooking lessons, tree planting and maintenance
classes, harvest festivals, and art creation can bring a deeper
connection to the landscape and disseminate information about
publicly available food resources.
73
URBAN DESIGN
Urban design that integrates the urban forest into streets and
publics enhances livability for all residents of a city, both through
principles of environmental psychology and biophilia put into
practice by design, and through incorporating and enhancing the
ecosystem services trees provide.
Thoughtful urban design plays an essential role in creating
livable cities, in large part by responding to wide streetscapes
and tall buildings in downtowns through the creation of human-
scale spaces. Trees play an essential role in urban design,
particularly when planted to subdivide larger areas. Street trees
create a “linear sequence,” making an architectural (or spatial)
rhythm for passers-by. (Gehl, 2010)
This linear sequence of tree trunks serves as a visual vertical
plane and separates pedestrians from other modes of
transportation, promoting a pedestrian’s sense of safety from
moving vehicles. The regular spacing of trees builds continuous
tree canopies over sidewalks and streets, creating a ceiling
plane and providing shade for pedestrians. Both offer a
reassuring sense of enclosure and human comfort on city streets
and in neighborhoods.
Trees in parks, plazas, and other public spaces are also
significant contributors to urban environments and are
typically included holistically in the initial design of those
places; in contrast, streetscapes tend to evolve with changing
development. Street trees provide a wide range of urban
design benefits.
These benefits include:
• The creation or continuation of vistas;
• Establishing a more human scale at street level in
cities where the built scale is very large;
• Providing a visual contrast in form, texture, color
and seasonal changes to the buildings; or
• Contributing to the element of mystery by hiding
and revealing city elements. (Bell, 2005)
Trees can also provide windbreaks either from downdrafts from
tall buildings or protection from cold winter winds.
SCALE + FORM
The scale and form of trees play a significant role in creating a
balanced streetscape and inviting places for people to socialize
and gather. Typically, large trees with broad canopies are best
in both dense urban centers and neighborhoods because their
height balances that of tall buildings, creating the effect of a
“step-back,” and the broad trunks and spreading canopies tend
to create more human-scaled spaces, as described above.
Most tree forms are appropriate in streetscapes, with a
significant exception being columnar trees. These do not create
a ceiling plane or provide adequate shade on sidewalks and
streets and are generally better suited for specific purposes,
such as creating hedges on private property or within parks.
By evaluating the permitted building heights, form-based codes,
and available soil volumes for tree planting, designers can
propose a range of tree scales, forms, and species to meet
municipal design and environmental goals. (See Neighborhood
Urban Forest Districts, below, for additional information).
In areas where existing soil volumes are small, such as highly-
paved downtowns, suspended pavement systems provide
opportunities to achieve the best urban design outcomes. Boise,
Idaho, has used this approach in their Downtown Streetscape
Standards & Specifications Manual.
Placemaking
Trees mediate between tall buildings and human-scale spaces
in Salt Lake City’s Downtown, and help reduce glare impacts.
74
TREE SPACING
Trees spacing requirements range considerably, from 15 to 40
feet apart in different cities. Criteria for tree planting are often
created without attention to the impact of street trees on urban
design or resident perceptions of safety and accessibility.
To be effective, street trees need to be reasonably close
together. If one objective is to create a line of columns
that separates visually and psychologically one pathway
from another, and if a further objective is to provide
a canopy of branches and leaves to walk under, then
the trees have to be planted close enough to do that.
(Jacobs, 1995)
James Urban, a landscape architect and expert in urban
arboriculture and soils, recommends using 20-foot on center
spacing for trees as a general rule (James Urban, 2003). Tree
canopy, longevity, and land-use and urban design contexts
should also be considered when developing spacing guidelines.
Residential Zones by Average Building Height
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STREET TREE SCALE
By requiring street trees of a specific scale related to urban
design criteria, such as building height and street width, Salt
Lake City’s public realm can become more livable and inviting.
Building height in residential and commercial areas follows
a predictable pattern in Salt Lake City, with the greatest
heights allowed in the Downtown and Sugar House Business
District areas (Height Zone C, below), where most buildings
are permitted a height of 6-10 stories, and up to 25 stories at
block corners. Intermediate heights of 3-5 stories are generally
permitted along major corridors leading from downtown and in
East Downtown (Height Zone B). Typical single-family districts
(Height Zone A) are one to two stories.
Street width also impacts scale requirements for trees, both for
urban design and practical considerations, such as providing
shade to asphalt streets to extend their lifespan. See the
drawings at right and on the following page for proposed tree
scale by height zones.
75
Recommended Minimum Mature Tree Scale for Height Zone A (1 - 2 story buildings)
Recommended Minimum Mature Tree Scale for Height Zone B (3 - 5 story buildings)
76
Recommended Minimum Mature Tree Scale for Height Zone C (6 - 10 story buildings)
77
TRANSITIONAL ELEMENTS
All urban forestry programs plan for “succession,” to achieve a
balance of differently-aged trees throughout the City. However,
thoughtful, well-designed structural elements can perform similar
functions in areas where many new trees need to go in or even
where a pronounced “gap” in a row of street trees occurs.
Judicious use of these elements can provide a transition as
young trees mature over decades or become more permanent
elements in locations where tree planting is simply impossible.
While no single structural element can simultaneously provide
the multiple benefits that a tree can, there some single functions
that can be replicated, namely:
1. Providing shade for energy conservation and cooling
(enhanced by misters, when feasible)
2. Creating vibrant, human-scaled social gathering places to
improve public health and community cohesion
3. Imbuing spaces with cultural meaning or “sense of place”
(public art, for example)
4. Enhancing active transportation routes and traffic calming
by adding visual interest and diversity to the streetscape
5. Growing vines on structures can provide limited air quality
and carbon sequestration benefits.
However, it is notable that there is a difference in the quality
of shade provided by trees and that supplied by structures.
Trees contribute to the enjoyment and complexity of the public
realm through movement, leaf patterns, and modulation of light.
(Jacobs, 1995) While some materials can mimic the translucence
of leaves, the biophilic response created by tree canopies is
practically impossible to replicate with built shade elements.
In response to the City’s immense need for shade and its goal
of achieving 25% canopy coverage by 2030, Phoenix, Arizona,
requires trees to be planted in what it calls the “Streetscape
Zone.” Phoenix defines the streetscape zone as the area
located behind the right-of-way curb with either landscaping or
public amenities. If a public utility easement prohibits trees from
being planted in the Streetscape Zone, then architecturally or
artistically compatible public amenities, including structural shade
elements, must be provided for the area (Section 1207).
Shade elements may include trellises, covered walkways
attached to buildings, or detached, architecturally compatible
shade structures. Structures must contain at least one side that is
50% open. (Phoenix, Zoning Ordinance, n.d.)
When new development cannot include trees, or when newly
planted trees are too small to provide shade or other benefits,
public amenities can act as either permanent or temporary
installations to provide similar aesthetic, environmental, and
community benefits.
The Phoenix Office of Arts and Culture has commissioned
multiple public art installations that act as shade canopies and
are typically included in more extensive infrastructure or urban
design projects. Commissioned works include bus shelters,
pedestrian bridges, and seating areas.
Matter Architecture Practice and landscape architects Gavan
& Barker Inc. integrated landscape architecture and civil
engineering to create “Bloomcanopy,” a hybrid public art/shade
structure. The canopy provides shade, and the plaza below was
designed to accommodate stormwater runoff. (Bloomcanopy,
2021)
Bloomcanopy. Photo by Matt Winquist
78
Shadow Play. Photo by Matt Winquist
The 2018 American Institute of Architects (AIA) Small Project
Award winner, “Shadow Play” sculpture (above) designed by
Howeler + Yoon Architecture, is a cluster of shade structures
placed in a former traffic median, providing pedestrians
shade and seating in the daytime and solar-powered light at
night. (AIA, 2021)
Cities can also use temporary public art installations to
provide shade for city residents in areas where planting trees
is not feasible due to conflicts with public utilities or narrow
street rights-of-way. Originating in Portugal, the Umbrella Sky
Project is an open-air museum that its creators describe as “A
simple idea that brings color and protection to public spaces
while transporting us into a fantasy world!” (Impact Plan,
2021) The project has traveled from Paris and Stockholm to
Pittsburgh and Miami, creatively providing city dwellers with
both shade and public art.
Bloomcanopy. Photo by Matt Winquist
79
The Umbrella Sky Project, 2021
Shadow Play at dusk. Photo by Matt Winquist Shade structure, photo by Landscape Structures 2021
Whimsical shade structure, Landscape Structures 2021
Commercially available shade structures may also be
appropriate for some locations, particularly to provide shade
as young trees mature. Shade structures should be sited
carefully so that they can be removed without damaging
adjacent infrastructure. Once the tree provides adequate
shade, structures can be removed and relocated where
they are needed.
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The City recognizes each tree designation by adding it to an
online interactive map that shows each tree’s location and
provides details on its significance and age.
Melbourne’s urban forest has received considerable attention
in recent years, as residents and visitors have been sending
e-mail “love letters” to individual trees. The City assigned
individual trees identification numbers and associated e-mail
addresses to allow more efficient reporting and assignment of
maintenance needs or problems. The City soon began receiving
e-mail messages to the trees on various topics, some even
sent from other countries. One typical example of an e-mail to a
Melbournian tree:
To: Algerian Oak, Tree ID 1032705
2 February 2015
Dear Algerian oak, Thank you for giving us oxygen. Thank
you for being so pretty. I don’t know where I’d be without
you to extract my carbon dioxide. (…Probably in heaven)
Stay strong, stand tall amongst the crowd. You are the gift
that keeps on giving.
We were going to speak about wildlife but don’t have
enough time and have other priorities, unfortunately.
Hopefully, one day our environment will be our priority.
(LaFrance, 2015)
The “positive unintended consequences” of the e-mail ID
underscores the connections many city residents find with
trees and how much they value them, as one City Councilor
noted. And, time permitting, some of the messages get a
response from the “tree,” which gives residents some insight
into the commitment of civil servants who keep the City running.
(LaFrance, 2015)
Artists have also used trees in creative placemaking strategies
by developing fruit tree sharing programs to reimagine the public
realm and revitalize public participation in urban spaces. Fallen
Fruit, for example, is a pair of artists who create site-specific
installations of fruit trees in public spaces to share. They have
also developed “Endless Orchard,” a website where participants
can map public fruit trees anywhere in the world. Currently, most
of the fruit tree locations mapped are in North America, but there
are also many locations mapped in South America, Australia,
Europe, and the Middle East.
These examples demonstrate how the urban forest provides
residents with opportunities to find and make meaning in the
places they inhabit and contribute to the stories that give urban
places their rich history. Telling and celebrating these stories is
another essential way to steward the urban forest.
NEIGHBORHOOD URBAN FOREST
DISTRICTS
Developing a range of tree species (selected for form, scale,
color, and other characteristics) to plant in specific areas of a
city can enhance the character of city neighborhoods and urban
districts. Economic success and community investment are
often linked to an identifiable character, or image, of a place or
neighborhood. The 9th & 9th neighborhood in Salt Lake City is
an excellent local example of this phenomenon.
Urban designers, landscape architects, and urban foresters
can collaborate to develop a selection of street trees defined
by shared aesthetic and ecologic characteristics that provide
a sense of place and emphasize transitions between different
city areas. At the same time, grouping trees in this way
can encourage biodiversity while simplifying irrigation and
maintenance regimes by creating streetscape tree stands with
similar water needs.
A connected grouping of trees selected using form, scale,
color, and texture criteria (what designers call a “plant palette,”)
protects the urban forest’s longevity by establishing context-
appropriate, durable, easy to maintain, and aesthetically
pleasing. The “palette approach” avoids excessive focus on
particular species (which can often devolve into preferences and
opinions or leave streetscapes vulnerable to species-specific
pests and diseases).
Melbourne, Australia, developed Urban Forest Precinct Plans
for each of its ten districts (or precincts) to achieve its citywide
goals for the urban forest. These plans allowed for greater
resident participation in the selection of design and performance
characteristics, as well as prioritizing planting areas.
A plant palette can be tailored to a specific project or define
neighborhood centers or even street types. Melbourne’s Urban
Forest Diversity Guidelines provide street tree recommendations
based on street location and characteristics. The matrix of tree
selection criteria considers street characteristics such as street
and sidewalk width, typical building height, number of traffic
lanes, and parking. (Melbourne, 2013)
URBAN FOREST STORIES
The City of Melbourne, Australia, adopted a heritage overlay
designation and an Exceptional Tree Register, which requires
developers to protect and retain trees with assessed cultural
significance. New buildings cannot impact the health of existing
trees and must be placed far enough away on the site to ensure
the tree is protected during construction. (Heritage Design
Guide, page 49). To be nominated for the “exceptional tree
register,” the tree must have aesthetic and horticultural value and
be rare or localized to the region. Each tree must be nominated
and then assessed by a third-party arborist who provides the
assessment to an expert panel to review for accuracy.
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Trees and other vegetation in Jordan Park create a “cooling island effect,” reducing ambient temperatures on nearby neighborhood streets.
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5
Growing
an Equitable
Urban Forest in
Salt Lake City
Action plans take a comprehensive view of a topic to address interconnected challenges,
develop priorities, find solutions, and build a long-term plan of action. Policymakers,
planners, and community members create and implement action plans to unite a broad
range of community stakeholders, non-profit organizations, private interests, institutions,
and governmental agencies around a shared cause.
Given the nature of action plans, the proposals in this chapter will necessarily require
collaboration between and within City departments, as well as collaboration between Salt
Lake City and outside actors.
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The Urban Forest is
Public Infrastructure
Salt Lake City should strive for a balance in preserving its urban
forest, which can be achieved by viewing the urban forest
through the lens of infrastructure. As cities grow and change,
there are always trade-offs and accommodations made to
increase housing, transportation, and employment choice for
residents while balancing the rights and responsibilities of
private property owners. Well-managed infrastructure systems
make our cities healthy, livable places, and require funding to
build and maintain. At the same time, infrastructure systems
regularly adapt and change in response to new technologies or
growth. By valuing the urban forest as public infrastructure with a
wide range of benefits, the City can make better, more informed
decisions about when and how to remove trees, and when and
where to plant them.
ABOUT THIS CHAPTER
This chapter outlines the strategic direction, goals,
objectives, and actions for Salt Lake City’s Urban Forest
based on the information analyzed and the needs
identified in previous chapters. The actions described
are intended to promote the successful protection and
equitable expansion of the urban forest.
The actions described have different timelines,
proposed as:
DEVELOP AN INTEGRATED
SYSTEMS APPROACH TO PUBLIC
INFRASTRUCTURE
All cities contain multiple, overlapping infrastructure systems,
many of which occupy the same space: for example,
transportation, utilities, and stormwater infrastructure systems all
use rights-of-way, as does 75% of Salt Lake City’s Urban Forest.
By integrating management of the Urban Forest’s ecosystem
services into the management other municipal infrastructure
systems, the City can meet its sustainability and livability goals
while reducing costs. Increased interdepartmental collaboration
would be necessary to achieve these goals and would result
in a clearer view of how and where these systems overlap and
connect, thereby reducing both costs and redundancies in
these systems.
This goal will provide environmental
and community benefits.
GOAL BENEFITS
Near-Term
Action
(5 years)
Mid-Term
Action
(10 years)
Long-Term
Action
(20 years)
STRATEGIC DIRECTION
DEFINITIONS
Strategic Direction: An essential line of progress along
which the city seeks to move in the long run,
and with which it seeks to align its resources and actions,
to realize its mission more fully.
Goal: A major aspiration that the city intends to realize
under a given strategic direction.
Objective: A concrete, measurable milestone on the way
to achieving a goal.
Action: A single step, or a coherent set of steps, that must
be taken to reach an objective.
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OBJECTIVE: AFFIRM SOCIAL AND ENVIRONMENTAL VALUE OF SALT LAKE CITY’S URBAN FOREST.
Near-Term Action
Adopt resolution declaring that the urban forest as a fundamental part of Salt Lake City’s infrastructure.
Develop asset management plan for Salt Lake City’s Urban Forest that incorporates inspection and
preventative maintenance.
Mid-Term Action Consider where Urban Forestry should be housed within the City’s Departmental Structure, considering
the location of its assets, impacts to City-owned infrastructure, and most viable funding sources.
OBJECTIVE: CREATE INTERNAL COORDINATION STRUCTURE BETWEEN MANAGERS OF THE CITY’S LIVING AND
BUILT INFRASTRUCTURE SYSTEMS AND DESIGNATE DUTIES AND AUTHORITY-HOLDERS.
Near-Term Action
Create core team of program managers to coordinate on projects that impact the urban forest. Initial
responsibilities of core team to include:
• Create annual work plan to describe areas of focus and report on progress.
• Develop “tree protection basics” training video to become required viewing for all existing and new
employees engaged in site plan review and ROW operations.
Mid-Term Action Create urban forest management policies and guidelines to be used by all City departments and
divisions working in the public right-of-way and in City parks and golf courses.
OBJECTIVE: INCLUDE THE VALUE OF URBAN FOREST ECOSYSTEM SERVICES AND “LOST BENEFITS”
IN TREE REPLACEMENT COSTS INTO TREE PRESERVATION ORDINANCE, TO CAPTURE FULL VALUE WHEN
TREES ARE REMOVED.
Near-Term Action
Using commercially available software platforms to quantify urban forests benefits, develop a new fee
structure for tree replacement or payment in lieu of tree replacement.
Incorporate “lost benefits” into calculation of fines for violations of tree protection ordinances.
IMPROVE GROWING CONDITIONS
FOR THE URBAN FOREST IN
CHALLENGING SITES
A “one-size-fits-all” approach to growing conditions is not an
optimal strategy for the urban forest. The two most important
factors are soil volume and adequate water. A soil volume
ordinance, for example, would ensure that adequate growing
space for trees is preserved, and prioritize tree health and full
canopy coverage in the ROW.
By providing a range of options for achieving optimal soil
volumes, such as suspended pavement systems, developers
could have different price points to meet the requirement. This
would also enable Salt Lake City to grow large, healthy trees in
highly paved areas that retain the most heat and are typically
most impacted by flooding.
This goal will provide environmental,
community and economic benefits.
GOAL BENEFITS
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PROTECT TREES ON CITY-OWNED
LAND AND IN THE ROW
According to the American Public Works Association, the best
tree preservation mechanisms are found “within zoning and
subdivision regulations for inspection and enforcement” of
urban forest protections. These regulations should identify
enforcement procedures and clarify authority and powers
(APWA, n.d.) In addition, more urban forestry plan reviewers,
inspectors, and enforcement staff trained in urban forestry, would
strengthen the City’s ability to protect the urban forest.
OBJECTIVE: AMEND THE CITY CODE TO STRENGTHEN TREE PROTECTION AND CODIFY ECOSYSTEM SERVICE VALUE.
Near-Term Action
Recommend changes to the zoning code to increase trees where they will mitigate environmental
impacts.
Reconcile contradictions in City Code.
Consider and account for impacts to the urban forest into policies governing International Fire Code
adoption.
Develop soil volume requirements for all projects using RDA funding sources.
Mid-Term Action
Set minimum annual tree maintenance thresholds (% of urban forest pruned annually) to cultivate
healthier, longer-lived, and safer public trees.
Amend zoning and subdivision ordinance to enhance urban forest protections, including:
• Evaluating sign regulations to provide options to business owners when tree growth is temporarily blocking
building signage and creating more opportunities for pedestrian-scale signs.
• Incorporate soil volumes and soil quality requirements into zoning code and city policies.
Develop an equitable strategy and fee structure to address negative environmental impacts related
to development in the Northwest Quadrant and their exemption from planting trees. For example, cash
payments in lieu of trees could be used to fund tree planting in impacted parts of the City.
OBJECTIVE: DEVELOP REALISTIC MEANS TO ENFORCE TREE PROTECTION REGULATIONS AND FACILITATE TREE SURVIVAL OF
NEWLY PLANTED TREES
Empowering the Urban Forestry Division to enforce tree protection ordinances would contribute to the growth of the urban forest by
increasing the likelihood of compliance during construction.
Near-Term Action Empower the Urban Forestry Division to issue stop work orders during construction activity.
Mid-Term Action
Require a cash bond for tree preservation at the beginning of development, which can be drawn
from for violations of the tree preservation plan. If there are no violations, the bond will be returned to
the developer.
• Hold bond for 3 years after Certificate of Occupancy is issued to ensure that trees are watered during
establishment periods.
This goal will provide environmental
and community benefits.
GOAL BENEFITS
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OBJECTIVE: CREATE REGULATIONS AND PROCESSES TO RESOLVE INFRASTRUCTURE CONFLICT
Developing new regulations for utility placement, such as requiring vaults and conduit, would help deliver the necessary conditions for the
urban forest to grow and thrive. A strategic approach to locating utility corridors and a system to resolve inevitable utility and tree conflicts
would save staff time and provide a data-based, transparent approach to share with City residents concerned about the loss of public trees
Near-Term Action
Develop a policy to prioritize infrastructure functions in the right-of-way.
Develop decision-making protocols to assist ROW managers.
Empower a clear final decision maker for ROW land use conflicts.
Develop process to proactively use GIS and other relevant technologies to anticipate and resolve
infrastructure conflicts on city-owned land.
Develop an “infrastructure solutions toolkit” along with a process to determine when and where to apply a
given solution.
Develop policy to incentivize burying overhead utility lines in vaults while maintaining or creating adequate
soil volumes for trees.
Require (rather than recommend) alternatives to impervious surfaces (such as stabilized, waterwise turf) on
fire access routes other than existing public roadways.
Create standard details for pervious surfaces that meet fire code requirements to provide to contractors.
Incorporate tree locations into project planning, and budget for utility protection measures in high-priority
locations.
Create a decision-tree and process for prioritization to implement mitigation measures described below.
Mid-Term Action Develop MOU with non-City agencies working in the public right-of-way and utility providers regarding
urban forest preservation.
IMPACTS OF UNRESOLVED
UTILITY CONFLICTS
GIS analysis demonstrates that there are nearly 10,000
available vacant tree planting locations in the public
right of way that do not conflict with the SLC Public
Utilities regulations regarding proximity to water and
sewer lines. This number represents a 58% decrease
from the total vacant planting sites (24,000) identified in
the 2019 Urban Forest Resource Analysis, which did not
account for utility location.
But when the strategic policy direction to maximize the
urban forest’s ROI is applied (selecting planting locations
using criteria to reduce urban heat island impacts, improve
urban design, and conserve energy), that number declines
to 200 tree planting locations—less than 1% of vacant
locations otherwise available.
By proactively planning for tree planting, land managers
can anticipate and resolve conflicts with utilities by ensuring
adequate funding to mitigate existing or future conflicts.
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MITIGATION MEASURES
FOR UNDERGROUND UTILITIES
INCLUDE A RANGE OF ACTIONS
AND TECHNOLOGIES
1. Locate utilities in a designated utility corridor that will
not conflict with tree roots.
2. Place utility lines in the street instead of the park
strip (particularly as opportunities become available
during road reconstruction projects).
3. If cities must locate utilities in park strips (without
existing trees, they should place utilities directly
behind the curb and not in the center of the park
strip, where trees are typically planted.
4. Place conduit that resists tree-roots during new
construction to accommodate current and future
proposals for utility lines as technologies change.
5. Plant trees with non-invasive roots or trees with a
small root ball.
6. Use physical or (non-toxic) chemical barriers near
utility lines to inhibit root growth. (Teske, 2013).
7. Combine utilities by using suspended pavement
systems for stormwater management and planting
trees. (In locations with clayey subsoils, an
underdrain for overflow stormwater can be placed
below the tree root zone).
8. Consolidate utilities and stack them vertically in one
predictable location (City & County of San Francisco,
2015).
9. Place utilities in precast concrete vaults
underground.
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OBJECTIVE: DEVELOP URBAN FOREST DESIGN MANUAL WITH CONSTRUCTION DETAILS
An urban forest design manual, which could be a chapter of a comprehensive sidewalk design manual, could incorporate specific
construction details for methods that would provide adequate soil volumes along with water conservation technologies and practices.
Near-Term Action
Develop a range of precedent design manuals from cities with similar climates.
Engage a consultant team with appropriate expertise to create a design manual for tree planting that
includes:
• climate-specific concerns
• water-conserving irrigation techniques
• pavement details to accommodate tree roots
• construction details for suspended pavement systems
• flexibility to expand or change as needed to accommodate emerging
best practices and lessons learned from implementation.
DEVELOP COMMUNICATION
CAMPAIGN ABOUT THE IMPORTANCE
OF THE URBAN FOREST
Communication and education about the urban forest and its
benefits is a crucial aspect of gaining public participation in the
work of stewardship. Information about the Urban Forest’s value
to multiple parts of community health and wellbeing should be
disseminated to all City departments, plan reviewers, developers,
and Salt Lake City residents.
Near-Term Action
Document and disseminate information on the benefits of Salt Lake City’s urban forest to communicate
to the public.
Sustainability and Public Utilities to develop communications to the public that explain and clarify the
role of trees in water conservation
Ascertain and share lessons learned from other cities and engage communities early to determine
needs and priorities before planting trees.
GOAL BENEFITS
This goal will provide community and
economic benefits.
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Maximize the Urban Forest’s
Return on Investment (ROI)
The living infrastructure of Salt Lake City’s urban forest provides economic, environmental, and community returns much greater than any
single built infrastructure system. To responsibly steward taxpayer dollars, the City can apply the investor metric of return on investment
(ROI) to determine infrastructure efficiently. Recent analysis demonstrates that for every single dollar invested directly into the urban forest,
the City receives $ 3.40 in annual benefits returned. Policy and planning decisions made to maximize these returns should guide the City’s
investments in the preservation and growth of the urban forest.
STRATEGIC DIRECTION
Selecting the correct tree form in urban environments can create “outdoor rooms” on the sidewalk.
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INCORPORATE THE URBAN
FOREST INTO ALL OF SALT LAKE
CITY’S PLANNING AND PROJECT
IMPLEMENTATION EFFORTS TO
MITIGATE ENVIRONMENTAL IMPACTS.
The urban forest intersects with all land use types in Salt Lake City.
By acknowledging impacts to and from the urban forest within all
the City’s master, area, and system plans, we can create conditions
for the City to achieve the urban forest vision outlined in Plan
Salt Lake. Coordinating plans for expanded tree canopy with
those for active transportation routes, for example, will increase
the attractiveness and comfort of pedestrian and bicycle routes
and can assist the City reducing emissions. Proactive planning
between the departments should incorporate the total value of the
urban forest in decision-making.
Near-Term Action
Assess all plans and implementation projects in or adjacent to the ROW alongside the tree inventory.
Integrate urban forest expansion with active transportation project planning from the earliest stages
of planning.
Collaborate with SLC Public Utilities stormwater quality program managers to incorporate urban forestry
into stormwater management policies and protocols, including the use of suspended pavement systems
in areas with small or no park strips.
Mid-Term Action
Incorporate canopy cover (or tree stocking) goals into all new master and area plans.
Update the 2010 Salt Lake City Open Space Acquisition Strategy to incorporate more specific guidance
related to trees. Base guidance on the findings of more recent analyses of the urban forest and goals
established in this Action Plan.
Investigate the feasibility of reducing asphalt or other street surfaces during road reconstruction and
replacing paved area with trees, tree wells, bioswales (stormwater infiltration galleries) or other types of
green infrastructure that can improve water quality.
GOAL BENEFITS
This goal will provide environmental,
community and economic benefits.
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CREATING AN URBAN
FOREST MASTER PLAN
• Investigate feasibility and needed resources to create a range
of thriving partnerships.
• Identify City Departments to partner with public agencies,
non-profits, and institutions with missions related to urban
forestry, education, sustainability, and public health to expand
the urban forest.
Church of Jesus Christ of Latter-day Saints
Salt Lake City School District
Salt Lake Community College
State of Utah
Utah Department of Transportation
University of Utah
Utah Transit Authority
A Master Plan (or master plan) for the urban forest that integrates
goals developed in partnership with communities is foundational
to maximizing urban forest benefits. The plan should incorporate
these actions:
• Create quantifiable strategies to mitigate negative environmental
impacts and associated adverse public health outcomes.
• Create performance metrics and targets based on Salt Lake City
Urban Forest Resource Analysis and livability assessment in this
plan, along with a schedule for data analysis and dissemination.
• Develop metrics and performance goals for planting trees in
areas with high rates of respiratory and heat-related illness.
• Investigate feasibility of increasing access to fruit trees
on public lands in areas with high rates of poverty and
health disparities.
• Examine feasibility of creating urban forest corridors linking the
City Creek, Red Butte, Emigration, and Parley’s Canyons to the
Jordan River.
• Develop Inventory of Urban Forest Assets in parks, golf courses,
and other City-owned land outside of the right of way.
• Evaluate and prioritize strategies for drought-mitigation and
efficient water use for trees in parks, golf courses and other
City-owned land outside of the right of way.
• Make recommendations for tree water-use zones in golf
courses and parks.
POTENTIAL INSTITUTIONAL OR AGENCY PARTNERS
These partnerships could include collaboration with:
• USU Forestry Extension to offer “Tree Steward” or “Citizen
Forester” training and certification to residents.
• Tree-related non-profit organizations to offer “Junior Forester,”
programming to school-age children.
• Local affordable housing non-profits to seek grant funds to
increase tree canopy on their properties, or to obtain funding
for efficient irrigation infrastructure in park strips adjacent to
their properties.
• Salt Lake County Storm-water Coalition to quantify and
evaluate impacts and to maximize benefits of urban trees on
water quality.
• National non-profits, such as American Forests or The Nature
Conservancy to expand canopy cover or tree stocking goals.
• Incorporate plans for cooling islands in parks and golf courses
into an Urban Forest Master Plan.
• Investigate feasibility of adding urban foresters to Golf Division
to maintain and expand tree cover in appropriate locations on
golf courses.
• Prioritize shaded food access routes in under-served areas of the
city that have low access to healthy and affordable food.
• Identify potential partners holding private and institutional lands
where an expanded, biodiverse urban forest would create
significant community benefits for future collaboration.
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OBJECTIVE: INCORPORATE MITIGATION TECHNIQUES INTO URBAN FORESTRY’S PLANTING STRATEGIES
While planning is necessary to maximize the urban forest return on investment (ROI), the urban forest is already delivering ecosystem
services to which we can optimize access. A combined approach that evaluates existing public land and rights-of-way in tandem with high-
need locations to mitigate urban heat island effect and poor air quality could dramatically increase the benefits of the urban forest where
they are most needed.
Using the analysis gathered for this Action Plan, Salt Lake City can focus its existing programming and prioritize resources in the short-term
to work with communities and non-profits to develop and implement planting and stewardship programs.
Near-Term Action
Prioritize the Westside 1000 Trees Initiative in census tracts identified in this action plan with the highest
rates of adverse health impacts and numbers of children. [place map here]
Use the GIS analysis created for this Action Plan to prioritize planting sites that mitigate adverse
environmental and public health impacts.
Perform GIS analysis identify parks and golf courses where additional trees would provide cooling.
Identify and prioritize large park strips that would give ample space for large trees, even allées (double
rows) of trees.
Plant large evergreens property bordering freeways to mitigate air pollution.
Implement a timeline for regular GIS analysis of water and sewer lines scheduled for abandonment and
plant trees in those locations.
Partner with Sustainability Department to perform GIS analysis of canopy potential and solar energy
potential in Salt Lake City. Identify areas of potential conflict and develop planting strategies to
accommodate both shade trees and solar panels in those areas.
Partner with Planning and Economic Development to develop incentives for using suspended
pavement systems in Downtown and other highly-paved areas.
• Ensure balanced, equitable incentives such as additional height for trees in suspended pavement. Trees
planted in grates (directly into soil) do not provide adequate mitigation in paved areas.
Mid-Term Action
Plant new trees in the Glendale Golf Course adjacent to streets and residential and commercial zoning
districts bordering the golf course to create cooling islands.
Plant new trees in the Rose Park Golf Course near streets and residential and manufacturing zoning
districts bordering the golf course to create cooling islands and mitigate air pollution.
Plant trees in Rosewood Park along park edges, along pathways, and to shade paved surfaces within
the park to harness cooling island effect.
Long-Term Action Plant deciduous trees on the north and east sides of streets to conserve energy (blocking the southern
and western sun in the summer and allowing it to passively warm buildings in the winter).
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OBJECTIVE: ADOPT A STRATEGIC APPROACH TO MINIMIZING AND AVOIDING PROPERTY DAMAGE CAUSED BY TREES
Property damage caused by falling tree limbs can be minimized by adequate funding for pruning and preservation. Proactive planning and
investment in protective technologies can also minimize damage to other City-owned infrastructure and private property.
Near-Term Action
Investigate feasibility of using root barriers to protect sidewalks from upheaval.
Investigate equitable approaches to sidewalk repair for lower-income residents through low- or no-
interest loans or grant programs.
Mid-Term Action
Incorporate funding for sidewalk protection strategies into project budgets during planning phases.
Develop funding sources for regular urban forest maintenance to avoid costs incurred for property
damage.
With adequate funding in place, Urban Forestry to collaborate with Streets Division to develop
inspection protocol and maintenance to proactively avoid potential tree and equipment conflicts prior
to street sweeping, snow removal, and paving.
With adequate funding in place, Urban Forestry to collaborate with Transportation Division to ensure
adequate sight distances are maintained at high-traffic intersections, and that signage and signals are
visible.
Long-Term Action Develop a program to fund the repair and mitigation of (tree caused) sidewalk and private property
damage at 100% to preserve trees and relieve cost burdens on lower-income residents.
OBJECTIVE: MITIGATE THE IMPACTS OF LEAF LITTER ON JORDAN RIVER WATER QUALITY
There are multiple design and engineering solutions to prevent leaf litter entering the Jordan River, which all have a range of costs and
impacts. These solutions would all likely require policy changes and additional funding sources.
Near-Term Action
Convene relevant Departments and Divisions (Public Lands, Public Services, Public Utilities,
Sustainability, and Urban Forestry) to develop policies and protocols to mitigate leaf litter impacts.
Perform an embodied energy analysis of increased street sweeping to mitigate water quality impacts.
Mid-Term Action
Investigate leaf litter collection incentives for residents and offer composted leaf mulch free of charge.
Create seasonal leaf cleanup crews and prioritize areas where excess leaf litter is most likely to
contribute to flooding or stormwater pollution.
Long-Term Action During ROW reconstruction projects, implement redesigned park strips to collect leaf litter and allow it
to decompose in place.
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DEVELOP ROBUST URBAN
FOREST OVERSIGHT
In its current form, Urban Forest oversight is provided by the
Parks, Natural Lands, Urban Forest, and Trails Advisory Board.
The urban forest is a system, and its oversight should be guided
by an approach that accounts for its interaction with other
systems. Because 75% of Salt Lake City’s urban forest is in public
rights-of-way, adjacent to a range of land uses and impacts, its
management and oversight needs often differ significantly from
that of parks and natural lands.
OBJECTIVE: CREATE A SUPERVISORY BODY FOCUSED ON THE SALT LAKE CITY’S URBAN FOREST.
A supervisory body which focuses on the urban forest as a living infrastructure system, including its impacts to and from built infrastructure
can provide specific guidance to meet the City’s strategic direction. In addition to members with professional expertise in arboriculture,
landscape architecture, ecology, land management, and sustainability, and environmental backgrounds supervisory bodies should include
residents from historically underserved neighborhoods and/or community-based organizations working with underrepresented and
underserved residents. and/or someone from the Mayor’s Equity & Inclusion Team
Near-Term Action
Create an Urban Forest Subcommittee to the Parks, Natural Lands, Urban Forest, and Trails Advisory
Board empowered to:
• Review public projects that impact the urban forest.
• Review, rank, prioritize, and make recommendations on capital improvement program funding
applications related to the urban forest
• Provide guidance on an urban forest master plan (see below).
• Provide advice and expertise on urban forestry issues to other boards, such as the planning commission
and transportation advisory board.
• Develop guidance and training materials for Community Councils
• Develop criteria for equity and inclusion in partnership with the administration.
Mid-Term Action
Evaluate the effectiveness and impact of the Urban Forest Subcommittee to determine its effectiveness
and determine if an Urban Forestry Board with a wider scope of duties is needed.
• Questions to evaluate include specific roles and responsibilities of the Board, the composition of the
board, and the scope of its authority.
GOAL BENEFITS
This goal will provide environmental
and community benefits.
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INCORPORATE PUBLIC HEALTH
OUTCOMES INTO URBAN FOREST
PLANTING AND PRESERVATION
STRATEGIES
In July 2021, Salt Lake City adopted a resolution declaring
racism a public health crisis. The City resolved to work with
County health officials and data partners to report and review
public health data. As a further step to acknowledge the legacy
of disinvestment in formerly redlined areas, the City can plant
trees in communities with low canopy cover that have higher
numbers of residents who are people of color and higher rates
of respiratory disease (see Chapter 3: Livability and the Urban
Forest in Salt Lake City for additional detail on the correlation
between historic redlining practices and lower levels of urban
forest canopy).
Mid-Term Action
Using metrics developed in an Urban Forest Master Plan, partner with public health agencies and
health care providers to meet goals for planting trees in areas with high rates of respiratory and heat-
related illness and to provide healthy food access in areas with higher rates of diet-related diseases.
Work with partner agencies to monitor rates of respiratory and heat-related illness and food access
correlate data with increased tree cover to determine if goals
are being met.
Develop programs and policies to create “edible landscapes for all.” (For more information, visit: https://
www.slc.gov/sustainability/rfea-2020-2021/
Develop community outreach program on urban forest benefits and stewardship with resident
ambassadors, partner agencies, and community-centered non-profits, including the Salt Lake County
Health Department and institutional partners such as the University of Utah.
GOAL BENEFITS
This goal will provide environmental,
community and economic benefits.
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PROVIDE STABLE, ADEQUATE
FUNDING FOR THE URBAN FOREST
TO MEET OR EXCEED LONG-TERM
CANOPY COVER (OR TREE STOCKING)
GOALS.
The urban forest’s return on investment grows as the trees
mature, and communities that are aware of the full range of
benefits that trees can provide are more likely to support
efforts to create stable funding streams. By quantifying the
value of environmental, economic, and community returns and
communicating these regularly, residents may take more interest
in the stewardship of public trees.
OBJECTIVE: UNDERTAKE AN ECONOMIC FEASIBILITY STUDY TO DETERMINE COSTS AND INVESTIGATE
POTENTIAL FUNDING STREAMS FOR EXPANDING THE URBAN FOREST
Near-Term Action
Public Utilities to determine applicability of charging impact fees for the urban forest, particularly as
related to stormwater management.
Sustainability and RDA to investigate and create development incentives to provide for adequate soil
volumes Downtown.
Engineering to update Roadway Impact Fee Facilities Plan (IFFP) to include suspended pavement
systems in highly paved areas of the City.
Public Lands to create an adopt-a-tree or tree memorial program in parks.
Investigate using capital improvement funds to underwrite urban forestry programming.
Investigate using a portion of tax receipts to fund the urban forest.
Mid-Term Action
Allocate a percentage of tax increment financing (TIF) toward urban forest expansion in RDA project
areas.
Using data gathered in feasibility study, place a general obligation bond on the ballot to allow voters to
decide on expanded urban forest maintenance, watering, and planting.
Develop a public-private partnership to fund trees and suspended pavements downtown (like the
Urban Forest Initiative of the Downtown Denver Partnership).
GOAL BENEFITS
This goal will provide environmental
and community benefits.
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OBJECTIVE: CREATE FRAMEWORK FOR PARTNERSHIPS BETWEEN MUNICIPAL AND STATE AGENCIES,
NONPROFITS, AND VOLUNTEERS TO EQUITABLY PRESERVE AND GROW THE URBAN FOREST.
Urban ecosystem boundaries, like all ecosystems, rarely conform to political boundaries. The greatest urban forest benefits will be
realized when we prioritize ecosystem service delivery regionally. Convening regional, municipal, non-profit, and institutional stakeholders
within water and airshed boundaries to establish benchmarks for urban forest expansion and establishing a regular schedule for updates
can enhance the urban forest benefits to Salt Lake City residents and neighboring municipalities.
Near-Term Action Partner for grant funding with urban forest non-profits to provide technical assistance and capacity-
building to City residents in underserved areas.
Mid-Term Action
Sustainability Department to create a public-private partnership to develop and maintain
neighborhood-based community orchards, prioritizing underserved areas of the city that have low
access to healthy and affordable food.
Youth and Family Services to partner with the Salt Lake City School District to promote tree planting on
school property. Students participating in the “Junior Forester” program could serve as ambassadors.
Long-Term Action
Partner with neighboring municipalities to add trees to high-volume traffic corridors, or other shared
areas with poor air quality.
Partner with owners of large parcels of land within City boundaries to increase canopy cover in
strategically important locations.
COORDINATE WITH REGIONAL
AGENCIES AND NEIGHBORING
MUNICIPALITIES ON URBAN
FOREST PLANNING AND EXPANSION
TO IMPROVE AIR AND WATER
QUALITY.
GOAL BENEFITS
This goal will provide environmental,
community and economic benefits.
Partner to equitably
distribute urban forest benefits
To implement the growth and maintenance of the urban forest at the scale needed to mitigate environmental and public health impacts,
partnership between the City with a range of organizations and agencies should be explored. At the same time, investigating and
implementing new and expanded mechanisms for funding the urban forest will increase the equitable distribution of its benefits.
STRATEGIC DIRECTION
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OBJECTIVE: EXPAND THE URBAN FOREST ON PRIVATELY-OWNED AND INSTITUTIONAL LAND IN SALT LAKE CITY
Near-Term Action
Economic Development to create incentives to preserve trees and grow the urban forest on and
adjacent to privately-owned land.
Planning to create policies and incentives to expand the urban forest on private land, including parking
lots, using existing regulations in the City code), including amendments to the City Code where feasible.
Mid-Term Action
Sustainability and Community and Neighborhoods to partner with private landowners to implement
solutions in challenging locations with significant environmental impact mitigation potential (for
example, on steep slopes adjacent to freeways).
Regional stakeholder to convene institutional partners to develop goals, objectives, actions, and
funding strategies to expand the urban forest on their lands.
IMPLEMENT EQUITY THROUGH
IRRIGATION DISTRIBUTION
There are a range of opportunities in Salt Lake City related to
efficiently irrigating public trees, which should be evaluated
for cost and benefit. Because the City currently requests that
residents water trees, this can create a burden on lower income
households which may lack the means to install a sprinkler
system or simply lack the time to water trees. Because properties
change hands and tenants move, there is also less consistency
in tree watering, which negatively impacts the health of the urban
forest.
OBJECTIVE: PUBLIC UTILITIES TO PROMOTE AND DEVELOP REBATE AND LOAN PROGRAMS FOR EFFICIENT
SPRINKLER SYSTEMS ON PRIVATE PROPERTY AND IN PARK STRIPS.
Near-Term Action
Promote California Avenue and Concord Street demonstration project of waterwise tree species
and efficient irrigation. Create a “video tour” of the project to share with Community Councils, other
interested community groups, and on social media.
Promote 900 South Stormwater Wetland (900 S and 900 West) demonstration project of waterwise tree
species and efficient irrigation
Develop a regular schedule to promote www.slcgardenwise.com on social media, including information
on watering trees.
Promote existing rebates program on efficient sprinkler nozzles and rain shut off sensors.
Mid-Term Action
Develop low or zero-interest loan program for homeowners to purchase and install efficient
irrigation systems.
Partner with non-profits to develop sprinkler installation program.
GOAL BENEFITS
This goal will provide environmental,
community and economic benefits.
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OBJECTIVE: THE CITY ASSUMES IRRIGATION RESPONSIBILITY FOR ALL PARK STRIP TREES, BEGINNING IN THE
MOST IMPACTED NEIGHBORHOODS.
Delivering water to public trees would assist the City in accomplishing two of its foremost goals: conserving water and improving air quality
(through ensuring trees get the water they need to thrive and provide ecosystem services). It is likely the costliest option, not only related
to irrigation infrastructure and water costs, but also the high level of coordination with residents required as the City made this shift. This
would be an equitable solution, however, and will take time and significant planning and allocation of resources to implement.
Near-Term Action Explore the costs of engaging a third party to water newly planted trees throughout the establishment
period where developers are required to plant trees and integrate these costs into impact fees.
Mid-Term Action
Develop efficient irrigation plan and feasibility study to investigate costs and implications of City
control of irrigation in park strips.
Assume responsibility for watering park strip trees in locations where local urban heat island
effects are greatest.
Long-Term Action
Based upon the outcome of the master plan and feasibility study, the City assumes responsibility
for park strip irrigation infrastructure and watering.
Develop block length watering zones in park strips on existing residential blocks for improved irrigation
efficiency to conserve water.
Providing shade over bike lanes makes them a more attractive option in the summer months.
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Plan and Design the Urban Forest
in the Public Interest
Planning for the urban forest with an approach that combines urban design principles for creating inviting, attractive, and comfortable
places for people with environmental impact mitigation strategies is a central method to maximize urban forest returns. As the City grows,
public spaces (sidewalks, streets parks, and plazas) will become increasingly critical to maintaining livability. Designing the urban forest
to enhance its aesthetic and environmental benefits in our public spaces can also provide identity and imageability to Salt Lake City’s
neighborhoods and business districts.
PLAN FOR EQUITABLE URBAN FOREST
EXPANSION IN NEIGHBORHOODS
AND BUSINESS DISTRICTS
Reassessing the City’s existing tree planting program and
partnering with nonprofits and residents to expand the urban
forest in residential areas and business districts with greater
population densities and lower tree canopy rates can facilitate
equitable outcomes.
GOAL BENEFITS
This goal will provide environmental,
community and economic benefits.
STRATEGIC DIRECTION
OBJECTIVE: INVESTIGATE CANOPY POTENTIAL AND CREATE CANOPY COVER GOAL AND DEVELOP REGULAR
PROGRESS ASSESSMENT PROCESS
The creation of a city-wide canopy cover goal will allow the City to create benchmarks for mitigating air quality impacts, provide discrete
milestones to work towards, and a create a basis for the equitable distribution of urban forest benefits. This would need to be a collaboration
between multiple departments, including Sustainability, Public Lands, Community and Neighborhoods, and the City’s GIS specialists.
Golf courses and parks should be included as key contributors to tree canopy and planned for strategically to capture and enhance the
benefits they deliver to surrounding land uses.
Near-Term Action
Develop GIS analysis of tree canopy potential using existing conditions and evaluate effects of
improved soil conditions through modeling.
Schedule and budget for a citywide remote sensing LIDAR (Light Detection and Ranging) survey every
five years to assess progress towards tree canopy goal.
Develop a schedule to assess canopy cover expansion in areas of identified need to measure progress.
Mid-Term Action Provide canopy data to partner organizations and private property owners.
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RETHINK ROW TO ALLOCATE MORE
SPACE FOR TREES & PEDESTRIANS
Salt Lake City’s rights-of-way represent our largest and most
widely distributed public spaces throughout the municipality.
Integrating space for trees and people and reducing space
for private vehicles will prioritize the quality of life in
these public spaces and can produce positive social and
environmental outcomes. A combined approach that evaluates
existing public land and underutilized roadways in tandem with
the high-need locations to mitigate urban heat island effect and
poor air quality could dramatically increase the benefits of the
urban forest where they are most needed. A strategic approach
to increased plantings in underutilized roadways in Downtown,
for example, could increase cooling and decrease energy
demand where air temperatures are highest in the summer.
OBJECTIVE: DEVELOP CRITERIA FOR NEIGHBORHOOD AND DISTRICT TREE PLANTING STRATEGIES
Given the wide range of benefits trees deliver, a strategic approach to planting based on environmental and social criteria can
reap multiple dividends.
Near-Term Action
Develop localized tree age-distribution criteria to provide stable canopy cover that can maintain
air quality improvements over the long term.
Plant large canopy tree species in areas prone to flooding to intercept rainwater.
Plant trees to create microclimates that increase access to summer shade and winter sun.
Plant trees to strategically provide shade on roadways to increase asphalt lifespan.
GOAL BENEFITS
This goal will provide environmental,
community and economic benefits.
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OBJECTIVE: ON STREETS WITH LOW TRAFFIC VOLUMES, CREATE A STRATEGY TO REDUCE VEHICLE LANES,
AND LANE WIDTHS, WHERE SUPPORTED BY FUTURE TRAFFIC PROJECTION DATA.
Reclaiming public space from cars for the urban forest may reduce tree and utility conflicts. This process of reclaiming public space
could be made equitable, in part through a data-driven plan which re-allocates that street space based on both the socio-economic and
environmental health needs of the neighborhood, as well as the role of a given street within the larger transportation network.
Near-Term Action
Create a “tree benefit score” for streets based on an analysis of public health, environmental health,
population density, and energy conservation criteria to apply to all streets wider than 30 feet.
As street reconstruction projects are planned, apply tree benefit score to determine space
to allocate for trees.
Budget for tree planting and irrigation at the beginning of street reconstruction projects.
Consider required soil volumes during the initial phases of street project planning
and design development.
Mid-Term Action Develop plan for reducing lanes on City streets using existing and projected traffic volumes.
ENHANCE CITY’S IMAGE
AND LIVABILITY THROUGH
INCORPORATING PEDESTRIAN-FIRST
STREETSCAPE DESIGN.
Salt Lake City’s current approach to spacing is based on zoning
requirements to include a street tree for every 30 feet of building
frontage. This approach does not fully consider growing needs
and pedestrian comfort. Development of more robust regulations
based on urban design best practices for regular architectural
rhythm (spacing) for creation of continuous canopies, visual
separation from moving vehicles for improved perception of
safety, and alignment of trees to create sidewalk spaces that
mediate between the human and building scale will improve Salt
Lake City’s imageability.
OBJECTIVE: AMEND ZONING CODE TO INTRODUCE NEW URBAN DESIGN CRITERIA FOR SPACING AND SCALE OF TREES
Near-Term Action
Recommend new tree spacing requirements based on environmental benefit and urban design criteria.
Recommend tree height and scale at maturity requirements based on average heights in zoning districts.
Recommend including shade on all active transportation routes in the City’s revised
Complete Streets ordinance.
Require additional trees at transit stops and along transit routes.
GOAL BENEFITS
This goal will provide environmental,
community and economic benefits.
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DEVELOP URBAN FOREST DISTRICTS
THROUGHOUT RESIDENTIAL AND
COMMERCIAL AREAS TO ENHANCE
SENSE OF PLACE.
Designing the urban forest with forms, scales, colors, and
textures that change as neighborhoods do will enrich the public
realm and provide a visual and perceptible sense of place that
reinforces neighborhood identity.
OBJECTIVE: DEVELOP URBAN FOREST DESIGN GUIDELINES
Near-Term Action
In partnership with Mayor’s Office of Equity and Inclusion, Urban Forestry Division to develop
criteria for public priority ranking based on the full range of urban forest benefits to distribute as a
survey to residents.
Develop analysis of formal and informal neighborhood and business district boundaries paired with
public health and environmental impact data to develop preliminary urban forest district boundaries.
Create three alternative urban forest district maps for public review and selection that incorporate
different combinations of urban forest priorities selected by residents.
After urban forest district map is selected by residents, develop community engagement process using
Melbourne, Australia as a key precedent.
Host charette-style workshops with Community Councils, neighborhood groups, and develop guidance
on form, scale, color, and seasonal change for each urban forest districts.
Create district-specific tree lists that:
• meet community criteria (form, scale, and color)
• enhance environmental impact mitigation
• provide adequate shade
• enhance biodiversity
• enhance perceptible changes to place between one district and the next.
Incorporate shade structures into design guidelines as both interim and permanent shade strategies
Develop decision-making criteria for proposed time frame for shade structure implementation (i.e.,
temporary or permanent).
Incorporate feedback from SLC Arts Council on implementation strategies for shade-producing art
installations that can educate about the need for urban cooling.
GOAL BENEFITS
This goal will provide environmental,
community and economic benefits.
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