United States 

Department of 

Agriculture

Forest Service

Pacific Southwest 

Research Station

General Technical 

Report

PSW-GTR-205

December 2007

Community

Benefits, Costs, and Strategic Planting

Interior West

Tree Guide

Kelaine E. Vargas, E. Gregory McPherson, James R. Simpson, 

Paula J. Peper, Shelley L. Gardner, and Qingfu Xiao
The Forest Service of the U.S. Department of Agriculture is dedicated to the principle of 

multiple use management of the Nation’s forest resources for sustained yields of wood, 

water, forage, wildlife, and recreation. Through forestry research, cooperation with the 

States and private forest owners, and management of the National Forests and National 

Grasslands, it strives—as directed by Congress—to provide increasingly greater service 

to a growing Nation.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and 

activities on the basis of race, color, national origin, age, disability, and where applicable, 

sex, marital status, familial status, parental status, religion, sexual orientation, genetic 

information, political beliefs, reprisal, or because all or part of an individual’s income 

is derived from any public assistance program. (Not all prohibited bases apply to all 

programs.) Persons with disabilities who require alternative means for communication of 

program information (Braille, large print, audiotape, etc.) should contact USDA’s TARGET 

Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write 

USDA, Director, Office of Civil Rights, 1400 Independence Avenue, SW, Washington, DC 

20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal 

opportunity provider and employer.

Authors 

Kelaine E. Vargas is a landscape architect, E. Gregory McPherson is a research 

forester, James R. Simpson is a forest meteorologist, Paula J. Peper is an 

ecologist, and Shelley L. Gardner was a forester, U.S. Department of Agriculture, 

Forest Service, Pacific Southwest Research Station, Center for Urban Forest 

Research, Department of Plant Sciences, MS-6, University of California Davis, 

One Shields Ave., Davis, CA 95616; Qingfu Xiao is a research hydrologist, 

Department of Land, Air, and Water Resources, University of California Davis, 

One Shields Ave., Davis, CA 95616. Gardner is currently with the U.S. Department 

of Agriculture, Forest Service, Office of Communications, 1400 Independence 

Ave., SW, Washington, DC 20250.

This work was sponsored by U.S. Department of Agriculture, Forest Service, State 

and Private Forestry, Urban and Community Forestry Program.
Interior West Community Tree 

Guide: Benefits, Costs, and 

Strategic Planting

Kelaine E. Vargas, E. Gregory McPherson, James R. Simpson, 

Paula J. Peper, Shelley L. Gardner, and Qingfu Xiao

U.S. Department of Agriculture, Forest Service

Pacific Southwest Research Station

Albany, California

General Technical Report PSW-GTR-205

December 2007

Abstract

Vargas, Kelaine E.; McPherson, E. Gregory; Simpson, James R.; Peper, Paula 

J.; Gardner, Shelley L.; Xiao, Qingfu. 2007. Interior West community tree 

guide: benefits, costs, and strategic planting. Gen. Tech. Rep. PSW-GTR-205. 

Davis, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest 

Research Station. 105 p.

Even as they increase the beauty of our surroundings, trees provide us with a 

great many ecosystem services, including air quality improvement, energy conservation, stormwater interception, and atmospheric carbon dioxide reduction. 

These benefits must be weighed against the costs of maintaining trees, including 

planting, pruning, irrigation, administration, pest control, liability, cleanup, and 

removal. We present benefits and costs for representative small, medium, and 

large deciduous trees and coniferous trees in the Interior West region derived from 

models based on indepth research carried out in Albuquerque, New Mexico. Net 

benefits increase with tree size and differ based on location. A large tree planted 

opposite the west wall of a building provides the greatest benefit. Two hypothetical 

examples of planting projects are described to illustrate how the data in this guide 

can be adapted to local uses, and guidelines for maximizing benefits and reducing 

costs are given.

Keywords: Ecosystem services, Interior West, urban forestry, benefit-cost 

analysis.
vi

GENERAL TECHNICAL REPORT PSW-GTR-205 

In the Interior West region, trees play an environmental, cultural, and historical role in communities. The trees of 

Albuquerque’s Old Towne Plaza are featured here. (Photo courtesy of www.marblestreetstudio.com)
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

vii

Executive Summary

This report quantifies benefits and costs for representative small, medium, and 

large deciduous trees and coniferous trees in the Interior West region. The species 

chosen as representative are the goldenrain, honeylocust, white ash, and ponderosa 

pine trees (see “Common and Scientific Names” section). The analysis describes 

“yard trees” (those planted in residential sites) and “public trees” (those planted 

on streets or in parks). Benefits are calculated by using tree growth curves and 

numerical models that consider regional climate, building characteristics, air 

pollutant concentrations, and prices. Tree care costs and mortality rates are based 

on results from a survey of municipal and commercial arborists. We assume a 55 

percent survival rate over a 40-year timeframe. 

The measurements used in modeling environmental and other benefits of trees 

are based on indepth research carried out for Albuquerque, New Mexico. Given 

the Interior West region’s broad and diverse geographical area, this approach provides general approximations based on some necessary assumptions that serve as 

a starting point for more specific local calculations. It is a general accounting that 

can be easily adapted and adjusted for local planting projects. Two examples are 

provided that illustrate how to adjust benefits and costs to reflect different aspects 

of local urban forest improvement projects.

Large trees provide the most benefits. Average annual benefits increase with 

mature tree size and differ based on tree location. The lowest values are for yard 

trees on the southern side of houses, and the highest values are for yard trees on 

the western side of houses. Values for public trees are intermediate. Benefits range 

as follows: 

• $9 to $14 for a small tree

• $26 to $33 for a medium tree

• $69 to $78 for a large tree

• $20 to $29 for a conifer

Benefits associated with reduced energy use and increased aesthetic and other 

benefits reflected in higher property values account for the largest proportion of 

total benefits in this region. Reduced levels of stormwater runoff, air pollutants, 

and carbon dioxide (CO2) in the air are the next most important benefits. 

Energy conservation benefits differ with tree location as well as size. Trees 

located opposite west-facing walls provide the greatest net heating and cooling 

energy savings. Reducing heating and cooling energy needs reduces CO2 

emissions and thereby reduces atmospheric CO2. Similarly, energy savings that 

 Benefits and costs 

quantified

Average annual 

benefits
viii

GENERAL TECHNICAL REPORT PSW-GTR-205 

reduce demand from power plants account for important reductions in gases that 

produce ozone, a major component of smog, and other air pollutants. 

The benefits of trees are offset by the costs of caring for them. Based on our surveys of municipal and residential arborists, the average annual cost for tree care ranges 

from $7 to $17 per tree. (Values below are for yard and public trees, respectively.) 

• $7 and $11 for a small tree

• $8 and $13 for a medium tree

• $10 and $17 for a large tree

• $9 and $14 for a conifer

Planting costs, annualized over 40 years, are the greatest expense ($4 per tree 

per year). Pruning ($1 to $6 per tree per year) and removal and disposal annualized 

over 40 years ($2 to $3 per tree per year) are the next greatest costs. Public trees 

also incur administrative expense ($3 per tree per year). Trees were assumed to be 

planted in irrigated areas, so irrigation costs after establishment were assumed to 

be negligible (cost of water only). During the establishment period, additional costs 

for labor-intensive hand watering were estimated to be $1 per year for 5 years.

Average annual net benefits (benefits minus costs) per tree for a 40-year 

period differ by tree location and tree size and range from a low of $1 to a high of 

$61 per tree. 

• $1 for a small public tree to $7 for a small yard tree on the west side of a house

• $18 for a medium public or yard tree on the south side of a house to $25 for a 

medium yard tree on the west side of a house

• $59 for a large yard tree on the south side of a house to $68 for a large yard tree 

on the west side of a house

• $11 for a coniferous yard tree on the south side of a house to $20 for a 

coniferous yard tree on the west side of a house

Environmental benefits alone, including energy savings, stormwater runoff 

reduction, improved air quality, and reduced atmospheric CO2, are up to four times 

greater than tree care costs.

Net benefits for a yard tree opposite a west wall and a public tree are substantial 

for larger species when summed over the 40-year period (values below are for yard 

trees opposite a west wall and public trees, respectively): 

• $297 and $54 for a small tree

• $1,101 and $771 for a medium tree

• $3,040 and $2,612 for a large tree

Costs

Average annual net 

benefits

Net benefits summed 

over 40 years
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

ix

• $882 and $587 for a conifer

Yard trees produce higher net benefits than public trees, primarily because of 

lower maintenance costs.

To demonstrate ways that communities can adapt the information in this report 

to their needs, examples of two fictional cities interested in improving their urban 

forest have been created. The benefits and costs of different planting projects are 

determined. In the hypothetical city of Llano Creek, net benefits and benefit-cost 

ratios (BCRs; total benefits divided by costs) are calculated for a planting of 1,000 

trees (2 in) assuming a cost of $100 per tree, 55 percent survival rate, and 40-year 

analysis. Total benefits are $2,558,484, total costs are $579,943, and net benefits 

are $1,979,008 ($49.48 per tree per year). The BCR is 4.42:1, indicating that $4.42 

is returned for every $1 invested. The net benefits and BCRs (in parentheses) by 

mature tree size are:

• $5,134 (1.24:1) for 50 goldenrain trees

• $121,973 (2.71:1) for 150 honeylocust

• $1,787,738 (5.09:1) for 700 white ash

• $64,163 (2.27:1) for 100 ponderosa pine

Increased property values reflecting aesthetic and other benefits of trees (52 

percent) account for about half of the estimated benefits, and reduced energy 

costs (32 percent) equal approximately another third. Reduced stormwater runoff 

(8 percent), air quality improvement (5 percent), and atmospheric CO2 reduction 

(3 percent) make up the remaining benefits. 

In the fictional city of Salsola, long-term planting and tree care costs and 

benefits were compared to determine if a proposed policy that might favor planting 

small trees would be cost-effective compared to the current policy of planting large 

trees where space permits. Over a 40-year period, the net benefits are:

• $66 for a small tree

• $788 for a medium tree

• $2,531 for a large tree

Based on this analysis, the city of Salsola decided to strengthen its tree ordinance, requiring developers to create tree shade plans that show how they will 

achieve 50-percent shade over streets, sidewalks, and parking lots within 15 years 

of development.
GENERAL TECHNICAL REPORT PSW-GTR-205

Contents

1 Chapter 1: Introduction

1 The Interior West Region

5 Chapter 2: Benefits and Costs of Urban and Community Forests

5 Benefits

5 Saving Energy

7 Reducing Atmospheric Carbon Dioxide

9 Improving Air Quality

13 Reducing Stormwater Runoff and Improving Hydrology

15 Aesthetics and Other Benefits

18 Costs

19 Planting and Maintaining Trees

20 Conflicts With Urban Infrastructure

23 Chapter 3: Benefits and Costs of Community Forests in Interior West 

 Communities

23 Overview of Procedures

23 Approach

25 Reporting Results

25 Findings of This Study

25 Average Annual Net Benefits

29 Average Annual Costs

30 Average Annual Benefits

35 Chapter 4: Estimating Benefits and Costs for Tree Planting Projects in 

 Your Community

35 Applying Benefit–Cost Data

35 Llano Creek Example

40 City of Salsola Example

43 Increasing Program Cost-Effectiveness

43 Increasing Benefits

43 Reducing Program Costs

47 Chapter 5: General Guidelines for Selecting and Placing Trees

47 Guidelines for Energy Savings

47 Maximizing Energy Saving From Shading

49 Planting Windbreaks for Heating Savings

50 Selecting Trees to Maximize Benefits

50 Guidelines for Reducing Carbon Dioxide

52 Guidelines for Reducing Stormwater Runoff

53 Guidelines for Improving Air Quality Benefits
xi

Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

54 Guidelines for Avoiding Conflicts With Infrastructure

56 Guidelines for Maximizing Long-Term Benefits

59 Glossary

64 Common and Scientific Names

65 Acknowledgments

66 Metric Equivalents

66 References

79 Appendix 1: Additional Resources

81 Appendix 2: Benefit–Cost Information Tables

91 Appendix 3: Procedures for Estimating Benefits and Costs

91 Approach

91 Pricing Benefits and Costs

91 Growth Modeling

92 Reporting Results

93 Benefit and Cost Valuation

94 Calculating Benefits

96 Atmospheric Carbon Dioxide Reduction

98 Stormwater Benefits

99 Aesthetic and Other Benefits

101 Calculating Costs

101 Planting

101 Pruning

102 Tree and Stump Removal

102 Pest and Disease Control

102 Irrigation Costs

102 Other Costs for Public and Yard Trees

103 Calculating Net Benefits

105 Limitations of This Study
xii

GENERAL TECHNICAL REPORT PSW-GTR-205 

The green infrastructure is a significant component of communities in the Interior West region.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

Chapter 1: Introduction

The Interior West Region

From the cities of the high desert Southwest to the small towns of Texas’s Llano 

Estacado to the communities of Washington’s Columbia Plateau, the Interior 

West region contains a diverse assemblage of municipalities, including some 

of the fastest growing states in the United States. The region extends in a wide 

band from eastern Oklahoma across the Southwest, swings north into western 

Nevada, and includes most of eastern Washington and parts of southern Idaho 

(fig. 1). Boundaries correspond to Sunset Climate Zones 2 and part of 10 (Brenzel 

2001) and USDA Hardiness Zones 6 and 7. The climate1 in this region is hot in 

the summer, relatively mild in the winter, and semiarid. Average summer high 

temperatures range from the low 80s in Washington to the mid 90s in most of 

the southwestern parts of the region; winter low temperatures average in the 

low to mid 20s. Precipitation is scarce with annual rates between 8 inches in 

Albuquerque, New Mexico, and Reno, Nevada, to 20 inches in western Texas. 

Most of the precipitation falls as rain in the summer months, often accompanied 

by harsh thunderstorms, but snow is not uncommon in some parts of the region. 

Because of this difficult climate, trees in natural landscapes are scarce and often 

limited to riparian areas. Native species include hardy, drought-tolerant trees such 

as cottonwoods, New Mexico olive, quaking aspen, spruce, fir, and some maples 

(see “Common and Scientific Names” section). 

1 Words in bold are defined in the glossary.

Figure 1—The Interior West region extends in a wide band from eastern Oklahoma across the 

Southwest, swings north into western Nevada and includes most of eastern Washington and 

parts of southern Idaho. Albuquerque is the reference city for the region.

Geographic scope 

of the Interior West 

region
GENERAL TECHNICAL REPORT PSW-GTR-205 

As the communities of the Interior West continue to grow and change during 

the coming decades, growing and sustaining healthy community forests is integral 

to the quality of life residents experience. The urban forest is a distinctive feature 

of the landscape that protects us from the elements, cleans the water we drink and 

the air we breathe, and forms a connection to earlier generations who planted and 

tended the trees. 

The role of urban forests in enhancing the environment, increasing community 

attractiveness and livability, and fostering civic pride takes on greater significance 

as communities strive to balance economic growth with environmental quality and 

social well-being. The simple act of planting trees provides opportunities to connect residents with nature and with each other. Neighborhood tree plantings and 

stewardship projects stimulate investment by local citizens, businesses, and governments for the betterment of their communities (fig. 2). Community forests bring 

opportunity for economic renewal, combating development woes, and increasing 

the quality of life for community residents. 

Interior West communities can promote energy efficiency through tree planting 

and stewardship programs that strategically locate trees to save energy and minimize conflicts with urban infrastructure. The same trees can provide additional 

benefits by reducing stormwater runoff; improving local air, soil, and water quality; 

reducing atmospheric carbon dioxide (CO2); providing wildlife habitat; increasing 

property values; slowing traffic; enhancing community attractiveness and investment; and promoting human well-being.

Figure 2—Tree planting and stewardship programs provide opportunities for local residents to 

work together to build better communities.

Interior West communities can derive 

many benefits from 

community forests
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

Although trees can provide many benefits to residents of the Interior West, 

trees are generally not an inherent part of many of these ecosystems. Therefore, few 

native species may be available for planting, and those that are may be inappropriate for urban settings. There may be concern over the introduction of nonnative 

trees. They may prove to be invasive, particularly in riparian areas, provide habitat 

for nonnative fauna, or encroach on nearby native habitats. These concerns are 

valid, considering for example, the invasion of the tree of heaven along the Sacramento and American Rivers in California (Hunter 2000) and along the Rio Grande 

(Tellman 1997) and of Russian olive throughout the Western United States (Brock 

1998). Careful species choice in collaboration with your local extension agent can 

allay these concerns while allowing local communities to reap the many benefits of 

trees in urban areas.

This guide builds upon studies by the USDA Forest Service in Chicago and 

Sacramento (McPherson et al. 1994, 1997), and other regional tree guides from the 

Center for Urban Forest Research (McPherson et al. 1999b, 2000, 2003, 2004, 2005, 

2006a, 2006b, 2006c) to extend knowledge of urban forest benefits in the Interior 

West. The guide: 

• Quantifies benefits of trees on a per-tree basis rather than on a canopy cover basis 

(it should not be used to estimate benefits for trees growing in forest stands).

• Describes management costs and benefits.

• Details how tree planting programs can improve environmental quality, conserve energy, and add value to communities.

• Explains where residential yard and public trees should be placed to maximize 

their benefits and cost-effectiveness.

• Describes ways conflicts between trees and power lines, sidewalks, and buildings can be minimized.

• Illustrates how to use this information to estimate benefits and costs for 

local tree planting projects.

These guidelines are specific to the Interior West and are based on data and 

calculations from open-growing urban trees in this region. 

Street, park, and shade trees are components of all interior West communities, 

and they impact every resident. Their benefits are myriad. However, with municipal 

tree programs dependent on taxpayer-supported general funds, communities are 

forced to ask whether trees are worth the price to plant and care for over the long 

term, thus requiring urban forestry programs to demonstrate their cost-effectiveness (McPherson 1995). If tree plantings are proven to benefit communities, then 

monetary commitment to tree programs will be justified. Therefore, the objective of 

Scope defined

Audience and 

objectives
GENERAL TECHNICAL REPORT PSW-GTR-205 

this tree guide is to identify and describe the benefits and costs of planting trees in 

interior West communities—providing a tool for municipal tree managers, arborists, and tree enthusiasts to increase public awareness and support for trees (Dwyer 

and Miller 1999). 
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

Chapter 2: Benefits and Costs of Urban and 

Community Forests

This chapter describes benefits and costs of public and privately managed trees. The 

functional benefits and associated economic value of community forests are presented. Expenditures related to tree care and management are assessed—a necessary 

process for creating cost-effective programs (Dwyer et al. 1992, Hudson 1983).

Benefits

Saving Energy

Energy is essential to quality of life and for economic growth. Conserving energy 

by greening our cities is often more cost-effective than building new power plants. 

For example, while California was experiencing energy shortages in 2001, its 177 

million city trees were providing shade and conserving energy. Annual savings 

to utilities were an estimated $500 million in wholesale electricity and generation 

purchases (McPherson and Simpson 2003). Planting 50 million more shade trees in 

strategic locations would provide savings equivalent to seven 100-megawatt power 

plants. The cost of peak load reduction was $63 per kW, considerably less than 

the $150 per kW benchmark for cost-effectiveness. A recent study of the 22,000 

municipal park trees of Albuquerque states that the trees save approximately 

$117,000 in annual air conditioning costs and $53,000 in heating costs (Vargas et 

al. 2006). Utility companies in the Interior West and throughout the country can 

invest in shade tree programs as a cost-effective energy conservation measure to 

lower peak energy demands.

Trees modify climate and conserve building energy use in three principal 

ways (fig. 3):

• Shading reduces the amount of heat absorbed and stored by built surfaces.

• Evapotranspiration converts liquid water to water vapor and thus cools the air 

by using solar energy that would otherwise result in heating of the air.

• Reducing windspeed reduces the infiltration of outside air into interior spaces 

and heat loss, especially where conductivity is relatively high (e.g., glass windows) (Simpson 1998).

Summer temperatures in cities can be 3 °F to 8 °F warmer than temperatures 

in the surrounding countryside. This is known as the urban heat island effect. 

Trees and other vegetation can combat this warming effect at small and large scales. 

On individual building sites, trees may lower air temperatures up to 5 °F compared 

with outside the greenspace. At larger scales (6 mi2), temperature differences of 

more than 9 °F have been observed between city centers and more vegetated 

suburban areas (Akbari et al. 1992). 

How trees work to 

save energy

Trees lower 

temperatures
GENERAL TECHNICAL REPORT PSW-GTR-205 

For individual buildings, strategically placed trees can increase energy 

efficiency in the summer and winter. Because the summer sun is low in the east 

and west for several hours each day, solar angles should be considered (fig. 4). Trees 

that shade east, and especially, west walls help keep buildings cool. In the winter, 

allowing the Sun to strike the southern side of a building can warm interior spaces. 

However, the trunks and bare branches of deciduous trees that shade south- and 

east-facing walls during winter may increase heating costs by blocking 40 percent 

or more of winter sun (McPherson 1984). 

Figure 3—Trees save energy for heating and cooling by shading buildings, lowering summertime 

temperatures, and reducing windspeeds. Secondary benefits from energy conservation are reduced 

water consumption and reduced pollutant emissions by power plants. (Drawing by Mike Thomas)

Figure 4—Paths of the Sun on winter and summer solstices (from Sand 1991). Summer heat gain is 

primarily through east- and west-facing windows and walls. The roof receives most irradiance, but 

insulated attics reduce heat gain to living spaces. The winter sun, at a lower angle, strikes the southfacing surfaces.

Trees increase home 

energy efficiency 

and save money
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

Rates at which outside air infiltrates a building can increase substantially 

with windspeed. In cold, windy weather, the entire volume of air, even in newer 

or tightly sealed homes, may change every 2 to 3 hours. Windbreaks reduce 

windspeed and resulting air infiltration by up to 50 percent, translating into 

potential annual heating savings of 10 to 12 percent (Heisler 1986). Reductions in 

windspeed reduce heat transfer through conductive materials as well. Cool winter 

winds, blowing against windows, can contribute significantly to the heating load 

of buildings by increasing the gradient between inside and outside temperatures. 

Windbreaks reduce air infiltration and conductive heat loss from buildings. 

Trees provide greater energy savings in the Interior West than in milder climate 

regions because they can have greater effects during the hot summers and cold 

winters. In Denver, for example, trees were found to produce substantial cooling 

savings for an energy efficient two-story wood-frame house (McPherson et al. 

1993). A typical energy-efficient house with air conditioning requires about $240 

each year for cooling. A computer simulation demonstrated that three 25-ft tall 

trees—two on the west side of the house and one on the east—would save $64 

each year for cooling, a 27 percent reduction (1,160 kWh). Conserving energy 

by greening our cities is important because it can be more cost-effective than 

building new power plants (for more information, see the Center for Urban Forest 

Research’s research summaries “Green Plants or Power Plants?” and “Save Dollars 

with Shade” [Geiger 2001, 2002a]). In the Interior West region, there is ample 

opportunity to “retrofit” communities with more sustainable landscapes through 

strategic tree planting and care of existing trees. 

Reducing Atmospheric Carbon DioxideGlobal temperatures have increased since the late 19th century, with major warming 

periods from 1910 to 1945 and from 1976 to the present (IPCC 2001). Human activities, primarily fossil-fuel consumption, are adding greenhouse gases to the atmosphere, and current research suggests that the recent increases in temperature can 

be attributed in large part to increases in greenhouse gases (IPCC 2001). Higher 

global temperatures are expected to have a number of adverse effects, including 

increasing the number and extent of wildfires, an aspect of particular concern in 

the Interior West (McKenzie et al. 2004). Increasing frequency of extreme weather 

events will continue to tax emergency management resources. 

Urban forests have been recognized as important storage sites for carbon 

dioxide (CO2), the primary greenhouse gas (Nowak and Crane 2002). Private 

markets dedicated to reducing CO2 emissions by trading carbon credits are 

emerging (Chicago Climate Exchange 2007, CO2e.com 2007, McHale 2003). 

Carbon credits have sold for as much as EUR 33 per ton (~$40; European Climate 

Windbreaks reduce 

heat loss

Retrofit for more 

savings

Trees reduce CO2
GENERAL TECHNICAL REPORT PSW-GTR-205 

Exchange 2006), and the social costs of CO2 emissions are estimated to range 

from £4 to £27 per ton ($7 to $47 per ton) (Pearce 2003). For comparison, for 

every $20 spent on a tree planting project in Arizona, 1 ton of atmospheric CO2

was reduced (McPherson and Simpson 1999). As carbon trading markets become 

accredited and prices rise, these markets could provide monetary resources for 

community forestry programs.

Urban forests can reduce atmospheric CO2 in two ways (fig. 5):

• Trees directly sequester CO2 in their stems and leaves while they grow.

• Trees near buildings can reduce the demand for heating and air conditioning, 

thereby reducing emissions associated with power production.

On the other hand, vehicles, chain saws, chippers, and other equipment release 

CO2 during the process of planting and maintaining trees. And eventually, all trees 

die, and most of the carbon (CO2) that has accumulated in their structure is released 

into the atmosphere as CO2 during decomposition. The rate of release into the 

atmosphere depends on if and how the wood is reused. For instance, recycling of 

urban wood waste into products such as furniture can delay the rate of decomposition compared to its reuse as mulch. 

Typically, CO2 released during tree planting, maintenance, and other programrelated activities is about 2 to 8 percent of annual CO2 reductions obtained through 

sequestration and reduced power plant emissions (McPherson and Simpson 1999). 

Figure 5—Trees sequester 

carbon dioxide (CO2) as they 

grow and indirectly reduce CO2

emissions from power plants 

through energy conservation. 

At the same time, CO2 is 

released through decomposition 

and tree care activities that 

involve fossil-fuel consumption. 

(Drawing by Mike Thomas)

Some tree-related 

activities release CO2
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting



To provide a complete picture of atmospheric CO2 reductions from tree plantings, it 

is important to consider CO2 released into the atmosphere through tree planting and 

care activities, as well as decomposition of wood from pruned or dead trees. 

Regional variations in climate and the mix of fuels that produce energy to heat 

and cool buildings influence potential CO2 emission reductions. Albuquerque, New 

Mexico’s, average emission rate is 2,324 lbs of CO2 per MWh (U.S. EPA 2003), 

a very high amount owing to the large amount of coal (98 percent) in the mix of 

fuels used to generate power. Lubbock, Texas, on the other hand, has an average 

emission of 1,532 lbs of CO2 per MWh (U.S. EPA 2003) because its power comes 

entirely from natural gas. Regions powered mostly by hydroelectric sources have 

even lower averages, such as Spokane, Washington, with an average CO2 emission 

rate of 178 lbs of CO2 per MWh (U.S. EPA 2003). Cities in the Interior West with 

relatively high CO2 emission rates will see greater benefits from reduced energy 

demand relative to other areas with lower emissions rates.

A study of the municipal park trees of Albuquerque found that the publicly 

owned trees sequester about 735 tons of CO2 annually and reduce CO2 production 

by about 1,725 tons by reducing energy needs (Vargas et al. 2006). Approximately 

128 tons of CO2 is released from decaying trees and tree maintenance, with a positive net reduction in CO2 levels from trees of 2,331 tons.

Another study in Chicago focused on the carbon sequestration benefit of residential tree canopy. Tree canopy cover in two residential neighborhoods was estimated 

to sequester on average 0.112 lb per ft2, and pruning activities released 0.016 lb per 

ft2 (Jo and McPherson 1995). Net annual carbon uptake was 0.096 lb per ft2. 

Since 1990, Trees Forever, an Iowa-based nonprofit organization, has planted 

trees for energy savings and atmospheric CO2 reduction with utility sponsorships. 

Over 1 million trees have been planted in 400 communities with the help of 120,000 

volunteers. These trees are estimated to offset CO2 emissions by 50,000 tons annually. Based on an Iowa State University study, survival rates are an amazing 91 percent 

indicating a highly trained and committed volunteer force (Ramsay 2002). 

Improving Air Quality

Approximately 159 million people live in areas where ozone (O3) concentrations 

violate federal air quality standards. About 100 million people live in areas where 

dust and other small particulate matter (PM10) exceed levels for healthy air. Air 

pollution is a serious health threat to many city dwellers, causing asthma, coughing, headaches, respiratory and heart disease, and cancer (Smith 1990). Impaired 

health results in increased social costs for medical care, greater absenteeism, and 

reduced longevity. 

Reduced CO2

emissions

CO2 reduction 

through community 

forestry

Trees improve air 

quality
10

GENERAL TECHNICAL REPORT PSW-GTR-205 

Recently, the Environmental Protection Agency (EPA) recognized tree planting 

as a measure in State Implementation Plans for reducing O3. Air quality management districts have funded tree planting projects to control particulate matter. 

These policy decisions are creating new opportunities to plant and care for trees 

as a method for controlling air pollution (Luley and Bond 2002; for more information see www.treescleanair.org [USDA FS 2006] and the Center for Urban Forest 

Research’s research summary “Trees—The Air Pollution Solution” [Geiger 2006]). 

Urban forests provide a number of air quality benefits:

• They absorb gaseous pollutants (e.g., O3, nitrogen dioxide [NO2], and sulfur 

dioxide [SO2]) through leaf surfaces (fig. 6).

• They intercept small particulate matter (PM10) (e.g., dust, ash, pollen, smoke) 

(fig. 6).

• They release oxygen through photosynthesis.

• They transpire water and shade surfaces, which lowers air temperatures, 

thereby reducing O3 levels.

• They reduce energy use, which reduces emissions of pollutants from power plants, 

including NO2, SO2, PM10, and volatile organic compounds (VOCs) (fig. 6).

• They shade paved surfaces and parked cars, reducing hydrocarbon emissions 

(fig. 6).

Figure 6—Trees absorb gaseous pollutants, retain particles on their surfaces, and release oxygen and 

volatile organic compounds. By cooling urban heat islands and shading parked cars, trees can reduce 

ozone formation. (Drawing by Mike Thomas)
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

11

Trees may also adversely affect air quality. Most trees emit biogenic volatile 

organic compounds (BVOCs) such as isoprenes and monoterpenes that can 

contribute to O3 formation. The contribution of BVOC emissions from city trees 

to O3 formation depends on complex geographic and atmospheric interactions that 

have not been studied in most cities. Some complicating factors include variations 

with temperature and atmospheric levels of NO2. 

A computer simulation study for Atlanta suggested that it would be very difficult to meet EPA O3 standards in the region by using trees because of the high 

BVOC emissions from native pines and other vegetation (Chameides et al. 1988). 

The results, however, were not straightforward. A later study showed that although 

removing trees reduced BVOC emissions, any positive effect was overwhelmed by 

increased hydrocarbon emissions from natural and anthropogenic sources owing 

to the increased air temperatures associated with tree removal (Cardelino and 

Chameides 1990). A similar finding was reported for the Houston-Galveston Area, 

where deforestation associated with urbanization from 1992 to 2000 increased 

surface temperatures. Despite the decrease in BVOC emissions, O3 concentrations increased because of the enhanced urban heat island effect during simulated 

episodes (Kim et al. 2005). 

As well, the O3-forming potential of different tree species differs considerably 

(Benjamin and Winer 1998). Trees emitting the greatest relative amount of BVOCs 

are sweetgum, blackgum, sycamore, poplar, and oak (Nowak 2000) (see “Common and Scientific Names” section). In a study in the Los Angeles basin, increased 

planting of low BVOC-emitting tree species was shown to reduce O3 concentrations, 

whereas planting of medium and high emitters would increase overall O3 concentrations (Taha 1996). A study in the Northeastern United States, however, found 

that species mix had no detectable effects on O3 concentrations (Nowak et al. 

2000). Any potentially negative effects of trees on one kind of air pollution must 

also be considered in light of their great benefit in other areas such as absorption 

of other pollutants.

Trees absorb gaseous pollutants through leaf stomates—tiny openings in the 

leaves. Secondary methods of pollutant removal include adsorption of gases to 

plant surfaces and uptake through bark pores. Once gases enter the leaf they diffuse 

into intercellular spaces, where some react with inner leaf surfaces and others are 

absorbed by water films to form acids. Pollutants can damage plants by altering 

their metabolism and growth. At high concentrations, pollutants cause visible damage to leaves, such as spotting and bleaching (Costello and Jones 2003). Although 

some pollutants may pose health hazards to plants, pollutants such as nitrogenous 

gases can also be sources of essential nutrients for them.

Trees affect ozone 

formation

Trees absorb 

gaseous pollutants
12

GENERAL TECHNICAL REPORT PSW-GTR-205 

Trees intercept small airborne particles. Some particles that impact a tree are 

absorbed, but most adhere to plant surfaces. Species with hairy or rough leaf, twig, 

and bark surfaces are efficient interceptors (Smith and Dochinger 1976). Intercepted 

particles are often resuspended in the atmosphere when wind blows the branches, 

and rain will wash some particulates off plant surfaces. The ultimate fate of these 

pollutants depends on whether they fall onto paved surfaces and enter the stormwater system, or fall on pervious surfaces, where they are filtered in the soil.

Urban forests freshen the air we breathe by releasing oxygen as a byproduct of 

photosynthesis. Net annual oxygen production varies depending on tree species, 

size, health, and location. A healthy tree, for example a 32-ft tall ash, produces 

about 260 lb of net oxygen annually (McPherson 1997). A typical person consumes 

386 lb of oxygen per year. Therefore, two medium-sized, healthy trees can supply 

the oxygen required for a single person over the course of a year. 

Trees near buildings can reduce the demand for heating and air conditioning, 

thereby reducing emissions of PM10, SO2, NO2, and VOCs associated with electric 

power production. Reduced emissions from trees can be sizable. For example, 

a strategically located tree can save 100 kWh in electricity for cooling annually 

(McPherson and Simpson 1999, 2002, 2003). Assuming that this conserved electricity comes from a typical new coal-fired power plant in the Interior West, the tree 

reduces emissions of SO2 by 1.25 lb, NO2 by 0.39 lb (U.S. EPA 2003), and PM10

by 0.84 lb (U.S. EPA 1998). The same tree is responsible for conserving 60 gal of 

water in cooling towers and reducing CO2 emissions by 200 lb.

In Houston, Texas, the tree canopy was estimated to remove 60,575 tons of 

air pollutants annually with a value of nearly $300 million (Smith et al. 2005). The 

urban forest of Montgomery, Alabama (33 percent tree cover), removed 1,603 tons 

of air pollutants valued at $7.9 million (American Forests 2004). Chicago’s 50.8 

million trees were estimated to remove 234 tons of PM10, 210 tons of O3, 93 tons 

of SO2, and 17 tons of carbon monoxide in 1991. This environmental service was 

valued at $9.2 million (Nowak 1994).

Trees in a Davis, California, parking lot were found to improve air quality by 

reducing air temperatures 1 to 3 °F (Scott et al. 1999). By shading asphalt surfaces 

and parked vehicles, trees reduce hydrocarbon emissions (VOCs) from gasoline that 

evaporates out of leaky fuel tanks and worn hoses (for more information, see our 

research summary Where Are All the Cool Parking Lots? [Geiger 2002b]). These 

evaporative emissions are a principal component of smog, and parked vehicles are a 

primary source (fig. 7). In California, parking lot tree plantings can be funded as an 

air quality improvement measure because of the associated reductions in evaporative emissions. 

Trees intercept 

particulate matter

Trees release oxygen

Shade from trees 

prevents evaporative 

hydrocarbon 

emissions
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

13

Reducing Stormwater Runoff and Improving Hydrology

Urban stormwater runoff is a major source of pollution entering wetlands, streams, 

lakes, and oceans. Healthy trees can reduce the amount of runoff and pollutants 

in receiving waters (Cappiella et al. 2005). This is important because federal law 

requires states and localities to control nonpoint-source pollution, such as runoff 

from pavements, buildings, and landscapes. Trees are mini-reservoirs, controlling 

runoff at the source, thereby reducing runoff volumes and erosion of watercourses, 

as well as delaying the onset of peak flows. Trees can reduce runoff in several ways 

(fig. 8; for more information, see our research summary Is All Your Rain Going 

Down the Drain? [Geiger 2003]):

• Leaves and branch surfaces intercept and store rainfall, thereby reducing runoff 

volumes and delaying the onset of peak flows.

• Roots increase the rate at which rainfall infiltrates soil and the capacity of soil 

to store water, reducing overland flow.

• Tree canopies reduce soil erosion by diminishing the impact of raindrops on 

barren surfaces.

• Transpiration through tree leaves reduces soil moisture, increasing the soil’s 

capacity to store rainfall.

Rainfall that is stored temporarily on canopy leaf and bark surfaces is called 

intercepted rainfall. Intercepted water evaporates, drips from leaf surfaces, and 

flows down stem surfaces to the ground. Tree surface saturation generally occurs 

after 1 to 2 in of rain has fallen (Xiao et al. 2000). During large storm events, rainfall exceeds the amount that the tree crown can store, about 50 to 100 gal per tree. 

Figure 7—Trees planted to shade parking areas can reduce hydrocarbon emissions and improve 

air quality.

Trees reduce runoff
14

GENERAL TECHNICAL REPORT PSW-GTR-205 

The interception benefit is the amount of rainfall that does not reach the ground 

because it evaporates from the crown. As a result, the volume of runoff is reduced 

and the time of peak flow is delayed. Trees protect water quality by substantially 

reducing runoff during small rainfall events that are responsible for most pollutant 

washoff. Therefore, urban forests generally produce more benefits through water 

quality protection than through flood control (Xiao et al 1998, 2000). 

The amount of rainfall trees intercept depends on their architecture, rainfall 

patterns, and climate. Tree-crown characteristics that influence interception are 

the trunk, stem, and surface areas, textures, area of gaps, period when leaves 

are present, and dimensions (e.g., tree height and diameter). Trees with coarse 

surfaces retain more rainfall than those with smooth surfaces. Large trees generally 

intercept more rainfall than small trees do because greater surface areas allow for 

greater evaporation rates. Tree crowns with few gaps reduce throughfall to the 

Figure 8—Trees intercept a portion of rainfall that evaporates and never reaches the ground. Some 

rainfall runs to the ground along branches and stems (stemflow) and some falls through gaps or 

drips off leaves and branches (throughfall). Transpiration increases soil moisture storage potential. 

(Drawing by Mike Thomas)
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

15

ground. Species that are in leaf when rainfall is plentiful are more effective than 

deciduous species that have dropped their leaves during the rainy season.

Studies that have simulated urban forest effects on stormwater runoff 

have reported reductions of 2 to 7 percent. Annual interception of rainfall by 

Sacramento’s urban forest for the total urbanized area was only about 2 percent 

because of the winter rainfall pattern and sparsity of evergreen species (Xiao et al. 

1998). However, average interception in canopied areas ranged from 6 to 13 percent 

(150 gal per tree), similar to values reported for rural forests. Broadleaf evergreens 

and conifers intercept more rainfall than deciduous species in areas where rainfall 

is highest in fall, winter, or spring (Xiao and McPherson 2002).

In areas like the Interior West that suffer from drought, trees can play a 

valuable role in reducing the velocity of rainfall, which reduces peak flows into 

streams and allows stormwater more time to be absorbed into the soil, thereby 

recharging the groundwater. Tree roots and decomposing leaf litter reduce soil 

compaction, also allowing stormwater more time to percolate into the ground.

In Albuquerque, the municipal park tree canopy reduced runoff by more than 

11 million gal, with an estimated value of $56,000 (Vargas et al. 2006). The tree 

canopy of Montgomery, Alabama (33 percent), was estimated to reduce runoff by 

1.7 billion gal, valued at $454 million per 20-year construction cycle (American 

Forests 2004). 

Urban forests can provide other hydrologic benefits, too. For example, 

tree plantations or nurseries can be irrigated with partially treated wastewater. 

Infiltration of water through the soil can be a safe and productive means of water 

treatment. Reused wastewater applied to urban forest lands can recharge aquifers, 

reduce stormwater-treatment loads, and create income through sales of nursery 

or wood products. Recycling urban wastewater into greenspace areas can be an 

economical means of treatment and disposal, while at the same time providing 

other environmental benefits (USDA NRCS 2005).

Aesthetics and Other Benefits

Trees provide a host of aesthetic, social, economic, and health benefits that should be 

included in any benefit-cost analysis. One of the most frequently cited reasons that 

people plant trees is for beautification. Trees add color, texture, line, and form to the 

landscape, softening the hard geometry that dominates built environments. Research 

on the aesthetic quality of residential streets has shown that street trees are the single 

strongest positive influence on scenic quality (Schroeder and Cannon 1983). 

Consumer surveys have found that preference ratings increase with the 

presence of trees in the commercial streetscape. In contrast to areas without trees, 

Urban forests can 

treat wastewater

Beautification

Attractiveness of 

retail settings
16

GENERAL TECHNICAL REPORT PSW-GTR-205 

shoppers shop more often and longer in well-landscaped business districts and 

are willing to pay more for parking and up to 11 percent more for goods and 

services (Wolf 1999).

Research in public housing complexes found that outdoor spaces with trees 

were used significantly more often than spaces without trees. Facilitating interactions among residents, trees can contribute to reduced levels of domestic violence, 

as well as foster safer and more sociable neighborhood environments (Sullivan 

and Kuo 1996). 

Well-maintained trees increase the “curb appeal” of properties (fig. 9). Research 

comparing sales prices of residential properties with different numbers of trees 

suggests that people are willing to pay 3 to 7 percent more for properties with ample 

trees versus few or no trees. One of the most comprehensive studies of the influence 

of trees on home property values was based on actual sales prices and found that 

each large front-yard tree was associated with about a 1-percent increase in sales 

price (Anderson and Cordell 1988). A much greater value of 9 percent ($15,000) was 

determined in a U.S. Tax Court case for the loss of a large black oak on a property 

valued at $164,500 (Neely 1988). Depending on average home sales prices, the value 

of this benefit can contribute significantly to cities’ property tax revenues.

Scientific studies confirm that trees in cities provide social and psychological 

benefits. Humans derive substantial pleasure from trees, whether it is inspiration 

from their beauty, a spiritual connection, or a sense of meaning (Dwyer et al. 1992, 

Figure 9—Trees beautify a neighborhood, increasing property values and creating a more sociable 

environment. (Photo courtesy of Brian Jorgenson)

Public safety 

benefits

Property value 

benefits

Social and 

psychological 

benefits
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

17

Lewis 1996). After natural disasters, people often report a sense of loss if their 

community forest has been damaged (Hull 1992). Views of trees and nature from 

homes and offices provide restorative experiences that ease mental fatigue and 

help people to concentrate (Kaplan and Kaplan 1989). Desk workers with a view 

of nature report lower rates of sickness and greater satisfaction with their jobs 

compared to those having no visual connection to nature (Kaplan 1992). Trees 

provide important settings for recreation and relaxation in and near cities. The act 

of planting trees can have social value, as bonds between people and local groups 

often result. 

A series of studies on human stress caused by general urban conditions show 

that views of nature reduce the stress response of both body and mind (Parsons 

et al. 1998), improving general well-being. Urban green also appears to have a 

positive effect on the human immune system. Hospitalized patients who have views 

of nature and spend time outdoors need less medication, sleep better, have a better 

outlook, and recover more quickly than patients without connections to nature 

(Ulrich 1985). Skin cancer is a particular concern in the sunny Interior West region. 

Trees reduce exposure to ultraviolet light, thereby lowering the risk of harmful 

effects from skin cancer and cataracts (Tretheway and Manthe 1999). 

Certain environmental benefits from trees are more difficult to quantify 

than those previously described, but can be just as important. Noise can reach 

unhealthy levels in cities. Trucks, trains, and planes can produce noise that exceeds 

100 decibels, twice the level at which noise becomes a health risk. Thick strips 

of vegetation in conjunction with landforms or solid barriers can reduce some 

highway noise and have a psychological effect (Cook 1978), but if vegetation is used 

as the only noise barrier, the amount necessary to achieve measurable reductions 

in noise (~200 ft for a 10-dB reduction) may be impractical (U.S. Department of 

Transportation 1995). Other studies have shown that the performance of noise 

barriers is increased when used in combination with vegetative screens (van 

Rentergehm et al. 2002). 

Numerous types of wildlife inhabit cities and are generally highly valued by 

residents. For example, older parks, cemeteries, and botanical gardens often contain 

a rich assemblage of wildlife. Remnant woodlands and riparian habitats within 

cities can connect a city to its surrounding bioregion (fig. 10). Wetlands, greenways 

(linear parks), and other greenspace can provide habitats that conserve biodiversity 

(Platt et al. 1994). 

Urban forestry can provide jobs for both skilled and unskilled labor. Public 

service programs and grassroots-led urban and community forestry programs 

provide horticultural training to volunteers across the United States. Also, urban 

Human health 

benefits

Noise reduction

Wildlife habitat

Jobs and 

environmental 

education
18

GENERAL TECHNICAL REPORT PSW-GTR-205 

and community forestry provides educational opportunities for residents who 

want to learn about nature through firsthand experience (McPherson and Mathis 

1999). Local nonprofit tree groups and municipal volunteer programs often 

provide educational material and hands-on training in the care of trees and work 

with area schools.

Tree shade on streets can help offset the costs of maintaining pavement by 

protecting paving from weathering. The asphalt paving on streets contains stone 

aggregate in an oil binder. Tree shade lowers the street surface temperature and 

reduces heating and volatilization of the binder (McPherson and Muchnick 2005). 

As a result, the aggregate remains protected for a longer period by the oil binder. 

When unprotected, vehicles loosen the aggregate, and much like sandpaper, the 

loose aggregate grinds down the pavement. Because most weathering of asphaltconcrete pavement occurs during the first 5 to 10 years when new street tree 

plantings provide little shade, this benefit mainly applies when older streets are 

resurfaced (fig. 11). 

CostsThe environmental, social, and economic benefits of urban and community forests 

come, of course, at a price. Our survey of municipal foresters in Albuquerque, 

New Mexico, Sandy, Utah, and Logan, Utah, indicates that they are spending 

about $14 per tree annually. The greatest costs are for pruning ($4 per tree) and 

planting ($4 per tree). Removal and disposal ($2 per tree) and administration ($3 

Figure 10—Natural areas within cities are refuges for wildlife and help connect city dwellers with 

their ecosystems. (Photo courtesy of www.marblestreetstudio.com)

Shade can reduce 

street maintenance

Municipal costs of 

tree care
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

19

per tree) are the next most costly. Costs for infrastructure repair average about $1 

per tree annually. 

Annual expenditures for tree management on private property have not been 

well documented. Costs differ considerably, ranging from some commercial 

or residential properties that receive regular professional landscape service 

to others that are virtually “wild” and without maintenance. Our survey of 

commercial arborists in the Interior West indicated that expenditures typically 

range from $7 to $10 per tree. Expenditures are usually greatest for pruning, 

planting, and removal. 

Planting and Maintaining Trees

Planting costs include the cost of the tree and the cost for planting, staking, and 

mulching. Based on our survey of interior West municipal and commercial arborists, planting costs differ with tree size and range from $85 for a 10-gal tree to $400 

for a 3-in tree. Pruning cycles differ by city and by tree size and range from once a 

year to once every 3 years for training new trees to once in 5 to 10 years for large, 

mature trees. The cost for pruning young trees ranged from $4 to $10 for a public 

tree and from $20 to $95 for a yard tree; the cost to prune a large, mature tree 

ranged from $60 to $250 for public trees and from $150 to $450 for yard trees. 

Because of the region’s hot and dry summer climate, newly planted trees 

require additional watering in early years in order to successfully establish 

Figure 11—Although shade trees can be expensive to maintain, their shade can reduce the costs 

of resurfacing streets (McPherson and Muchnick 2005), promote pedestrian travel, and improve 

air quality directly through pollutant uptake and indirectly through reduced emissions of volatile 

organic compounds from cars.

Residential costs 

differ
20

GENERAL TECHNICAL REPORT PSW-GTR-205 

themselves. The costs of irrigation are estimated at $1 to $4 per year for the first 5 

years, mainly for the labor costs involved in visiting the trees with a water truck or 

other time-intensive method. Beyond the establishment period, it is assumed that 

trees have been planted into irrigated landscapes and therefore the cost of additional 

water for the trees is negligible.

At the end of a tree’s life, removal costs can be substantial, especially for 

large trees. Removal and disposal of small trees (under 3 in diameter at breast 

height [d.b.h.]) cost between $30 and $95, but a large tree may cost several 

thousand dollars to remove. According to our survey, total costs for removal of 

trees and stumps average approximately $35 per in d.b.h. for yard trees and $22 

per in d.b.h. for public trees.

Conflicts With Urban Infrastructure

Like other cities across the United States, communities in the Interior West region 

are spending millions of dollars each year to manage conflicts between trees and 

power lines, sidewalks, sewers, and other elements of the urban infrastructure. 

According to our survey, cities in the region are spending about $2 to $5 per tree 

annually on sidewalk, curb, and gutter repair costs. This amount is far less than the 

$11.22 per tree reported for 18 California cities (McPherson 2000). In addition, the 

figures for California apply only to street trees and do not include repair costs for 

damaged sewer lines, building foundations, parking lots, and various other hardscape elements. 

In some cities, decreasing budgets are increasing the sidewalk-repair backlog 

and forcing cities to shift the costs of sidewalk repair to residents. This shift has 

significant impacts on residents in older areas, where large trees have outgrown 

small sites and infrastructure has deteriorated. It should be noted that trees are not 

always fully responsible for these problems. In older areas, in particular, sidewalks 

and curbs may have reached the end of their 20 to 25 year service life, or may have 

been poorly constructed in the first place (Sydnor et al. 2000). 

Efforts to control the costs of these conflicts are having alarming effects on urban 

forests (Bernhardt and Swiecki 1993, Thompson and Ahern 2000): 

• Cities are downsizing their urban forests by planting smaller trees. Although 

small trees are appropriate under power lines and in small planting sites, they 

are less effective than large trees at providing shade, absorbing air pollutants, 

and intercepting rainfall.

• Thousands of healthy urban trees are lost each year and their benefits forgone 

because of sidewalk damage, the second most common reason that street and 

park trees were removed.

Tree roots can 

damage sidewalks

Costs of conflicts
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

21

• Most cities surveyed were removing more trees than they were planting. 

Residents forced to pay for sidewalk repairs may not want replacement trees.

Cost-effective strategies to retain benefits from large street trees while 

reducing costs associated with infrastructure conflicts are described in Reducing 

Infrastructure Damage by Tree Roots (Costello and Jones 2003). Matching the growth 

characteristics of trees to the conditions at the planting site is one important strategy. 

Tree roots can also damage old sewer lines that are cracked or otherwise 

susceptible to invasion. Sewer repair companies estimate that sewer damage is 

minor until trees and sewers are over 30 years old, and roots from trees in yards are 

usually more of a problem than roots from trees in planter strips along streets. The 

latter assertion may be due to the fact that sewers are closer to the root zone as they 

enter houses than at the street. Repair costs typically range from $100 for sewer 

rodding (inserting a cleaning implement to temporarily remove roots) to $1,000 or 

more for sewer excavation and replacement.

Most communities sweep their streets regularly to reduce surface-runoff pollution entering local waterways. Street trees drop leaves, flowers, fruit, and branches 

year round that constitute a significant portion of debris collected from city streets. 

When leaves fall and rains begin, tree litter can clog sewers, dry wells, and other 

elements of flood-control systems. Costs include additional labor needed to remove 

leaves, and property damage caused by localized flooding. Wind and ice storms 

also incur cleanup costs.

The cost of addressing conflicts between trees and power lines is reflected in 

electric rates. Large trees under power lines require more frequent pruning than 

better suited trees, which can make them appear less attractive (fig. 12). Frequent 

crown reduction reduces the benefits these trees could otherwise provide. Moreover, increased costs for pruning are passed on to customers. 

Cleaning up after 

trees

Large trees under 

power lines can be 

costly

Figure 12—Large trees planted under power lines can 

require extensive pruning, which increases tree care costs 

and reduces the benefits of those trees, including their 

appearance.
22

GENERAL TECHNICAL REPORT PSW-GTR-205 

Trees in Interior West communities enhance quality of life. 

Brian Jorgenson
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

23

Chapter 3: Benefits and Costs of Community Forests in 

Interior West Communities

This chapter presents estimated benefits and costs for trees planted in typical 

residential yards and public sites. Because benefits and costs differ with tree size, 

we report results for representative small, medium, and large deciduous trees and 

for a representative conifer.

Estimates are initial approximations as some benefits and costs are intangible 

or difficult to quantify (e.g., impacts on psychological health, crime, and violence). 

Limited knowledge about physical processes at work and their interactions makes 

estimates imprecise (e.g., fate of air pollutants trapped by trees and then washed 

to the ground by rainfall). Tree growth and mortality rates are highly variable 

throughout the region. Benefits and costs also differ, depending on differences in 

climate, pollutant concentrations, maintenance practices, and other factors. Given 

the Interior West region’s broad area, with many different climates, soils, and 

types of community forestry programs, the approach used here provides first-order 

approximations. It is a general accounting that can be easily adapted and adjusted 

for local planting projects. It provides a basis for decisions that set priorities and 

influence management direction (Maco and McPherson 2003).

Overview of Procedures

Approach

In this study, annual benefits and costs are estimated over a 40-year planning 

horizon for newly planted trees in three residential yard locations (east, south, and 

west of the residence) and a public streetside or park location (app. 2). Henceforth, 

we refer to trees in these hypothetical locations as “yard” trees and “public” trees, 

respectively. Prices are assigned to each cost (e.g., planting, pruning, removal, 

irrigation, infrastructure repair, liability) and benefit (e.g., heating/cooling energy 

savings, air pollutant mitigation, stormwater runoff reduction, and aesthetic and 

other benefits measured as increases in property value) through direct estimation 

and implied valuation of benefits as environmental externalities. This approach 

makes it possible to estimate the net benefits of plantings in “typical” locations by 

using “typical” tree species. More information on data collection, modeling procedures, and assumptions can be found in appendix 3.

To account for differences in the mature size and growth of different tree 

species, we report results for a small (goldenrain tree), medium (honeylocust), 

and large (white ash) deciduous tree and a conifer (ponderosa pine) (figs. 13 to 16) 

(see “Common and Scientific Names” section). Tree dimensions are derived from 
24

GENERAL TECHNICAL REPORT PSW-GTR-205 

growth curves developed from park and street trees in Albuquerque, New Mexico 

(Vargas et al. 2006) (fig. 17).

Frequency and costs of tree management are estimated based on surveys with 

municipal foresters from Albuquerque, New Mexico; Sandy City, Utah; and Logan, 

Utah. In addition, commercial arborists from Salt Lake City, Utah; Austin, Texas; 

Logan, Utah; and El Prado, New Mexico, provided information on tree management costs on residential properties. 

Benefits are calculated with numerical models and data both from the region 

(e.g., pollutant emission factors for reduced emissions owing to energy savings) and 

from local sources (e.g., Albuquerque climate data for energy effects). Regional 

electricity and natural gas prices are used in this study to quantify energy savings. 

Damage costs and control costs are used to estimate willingness to pay. For 

example, the value of stormwater runoff reduction from rainfall interception by 

trees is estimated by using marginal control costs. If a community or developer is 

willing to pay an average of $0.01 per gal of treated and controlled runoff to meet 

minimum standards, then the stormwater runoff mitigation value of a tree that 

intercepts 1,000 gal of rainfall, eliminating the need for control, should be $10.

Figure 13—The goldenrain tree represents small trees in this 

guide. (Photo courtesy of Brian Jorgenson)

Figure 14—The honeylocust represents medium trees in this 

guide. (Photo courtesy of Brian Jorgenson)

Tree benefits based 

on numerical models

Tree care costs 

based on survey 

findings
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

25

Figure 15—The white ash represents large trees in this guide. Figure 16—The ponderosa pine represents coniferous trees in 

this guide.

Reporting Results

Results are reported in terms of annual value per tree planted. To make these 

calculations realistic, however, mortality rates are included. Based on our survey of 

regional municipal foresters and commercial arborists, this analysis assumes that 

45 percent of the planted trees will die over the 40-year period. Annual mortality 

rates are 3 percent per year for the first 5 years and 0.85 percent per year for the 

remainder of the 40-year period. This accounting approach “grows” trees in different locations and uses computer simulation to directly calculate the annual flow of 

benefits and costs as trees mature and die (McPherson 1992). In appendix 2, results 

are reported at 5-year intervals for 40 years. 

Findings of This Study

Average Annual Net Benefits

Average annual net benefits (benefits minus costs) per tree over a 40-year period 

increase with mature tree size (for detailed results see app. 2): 

• $1 to $7 for a small tree

• $18 to $25 for a medium tree

Tree mortality 

included

Average annual net 

benefits increase 

with tree size
26

GENERAL TECHNICAL REPORT PSW-GTR-205 

Figure 17—Tree growth curves are based on data collected from park trees in Albuquerque, New 

Mexico. Data for representative small, medium, and large deciduous and conifer trees are for 

the goldenrain tree, honeylocust, white ash, and ponderosa pine, respectively. Differences in leaf 

surface area among species are most important for this analysis because functional benefits such 

as summer shade, rainfall interception, and pollutant uptake are related to leaf area.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

27

• $59 to $68 for a large tree

• $11 to $20 for a conifer

Our findings demonstrate that average annual net benefits from large trees 

like the white ash are substantially greater than those from small trees like the 

goldenrain tree. Average annual net benefits for the small, medium, and large 

deciduous public trees are $1, $18, and $60, respectively. Conifers provide an 

intermediate level of benefits, on average $14 for a public tree. The largest average annual net benefits, however, stem from yard trees opposite the west-facing 

wall of a house: $7, $25, $68, and $20, for small, medium, and large deciduous 

trees and the conifer, respectively.

At year 40, the large yard tree opposite a west wall produces a net annual 

benefit of $174. In the same location, 40 years after planting, the goldenrain tree, 

honeylocust, and ponderosa pine produce annual net benefits of $14, $49, and $54. 

Forty years after planting at a typical public site, the small, medium, and large 

deciduous trees and the conifer provide annual net benefits of $8, $34, $164, and 

$40, respectively.

Net benefits for a yard tree opposite a west house wall and a public tree also 

increase with size when summed over the entire 40-year period:

• $297 (yard) and $54 (public) for a small tree

• $1,101 (yard) and $771 (public) for a medium tree

• $3,041 (yard) and $2,638 (public) for a large tree

• $882 (yard) and $587 (public) for a conifer

Twenty years after planting, average annual benefits for all trees exceed costs 

of tree planting and management (tables 1 and 2). For a large white ash in a yard 20 

years after planting, the total value of environmental benefits alone ($30) is more 

than five times the total annual cost ($5.75). Environmental benefits total $13, $22, 

and $14 for the goldenrain tree, honeylocust, and ponderosa pine, and tree care 

costs are mostly lower, $2, $5, and $6, respectively. Adding the value of aesthetics 

and other benefits to the environmental benefits results in even greater net benefits. 

Net benefits for public trees at 20 years ($6, $20, $39, and $10 for small, 

medium, and large deciduous trees and the conifer) are less than yard trees for two 

main reasons (table 2): public tree care costs are greater because public trees generally receive more intensive care than private trees; and energy benefits are lower for 

public trees than for yard trees because public trees are assumed to provide general 

climate effects, but not to shade buildings directly. 

Large trees provide 

the most benefits

Net benefits summed 

over 40 years

Year 20: 

environmental 

benefits exceed tree 

care costs

Net annual benefits 

at year 40
28

GENERAL TECHNICAL REPORT PSW-GTR-205 

Table 1—Estimated annual benefits and costs for a private tree (residential yard) opposite the westfacing wall 20 years after planting

Goldenrain tree

small tree

20 ft tall

20-ft spread

LSA = 168 ft2

Honeylocust

medium tree

26 ft tall

26-ft spread

LSA = 456 ft2

White ash

large tree

31 ft tall

29-ft spread

LSA = 988 ft2

Ponderosa pine conifer tree 23 ft tall 20-ft spread LSA = 235 ft2

Benefit category RU

Total 

value RU

Total 

value RU

Total 

value RU

Total 

value

Dollars Dollars Dollars Dollars

Electricity savings ($0.0788/kWh) 106 kWh 8.35 165 kWh 13.04 232 kWh 18.27 115.3 kWh 9.09

Natural gas savings ($0.0110/kBtu) 122 kBtu 1.34 262 kBtu 2.88 302 kBtu 3.32 82.1 kBtu 0.90

Carbon dioxide ($0.003/lb) 269 lb 0.90 460 lb 1.54 634 lb 2.12 300 lb 1.00

Ozone ($0.61/lb) 0.25 lb 0.15 0.40 lb 0.24 0.52 lb 0.32 0.35 lb 0.22

Nitrogen dioxide ($0.61/lb) 0.49 lb 0.30 0.77 lb 0.47 1.06 lb 0.65 0.53 lb 0.33

Sulfur dioxide ($1.42/lb) 0.40 lb 0.57 0.63 lb 0.90 0.87 lb 1.23 0.42 lb 0.60

Small particulate matter ($1.14/lb) 0.25 lb 0.29 0.36 lb 0.42 0.45 lb 0.51 0.30 lb 0.34

Volatile organic compounds ($0.19/lb) 0.09 lb 0.02 0.14 lb 0.03 0.19 lb 0.04 0.09 lb 0.02

Biogenic volatile organic compounds 

($0.19/lb) -1.41 lb - 0.27 -0.24 lb - 0.05 0.00 lb 0.00 - 0.24 lb - 0.05

Rainfall interception ($0.005/gal) 259 gal 1.30 430 gal 2.15 638 gal 3.19 393 gal 1.97

Environmental subtotal 12.93 21.62 29.64 14.42

Other benefits 2.39 9.65 22.93 6.96

Total benefits 15.31 31.27 52.57 21.38

Total costs 2.31 5.19 5.75 5.66

Net benefits 13.01 26.08 46.82 15.71

LSA = leaf surface area; RU = resource unit.

Table 2—Estimated annual benefits and costs for a public tree (street/park) 20 years after planting

Goldenrain tree

small tree

20 ft tall

20-ft spread

LSA = 168 ft2

Honeylocust 

medium tree 

26 ft tall 

26-ft spread 

LSA = 456 ft2

White ash

large tree

31 ft tall

29-ft spread

LSA = 988 ft2

Ponderosa pine 

conifer tree 

23 ft tall 

20-ft spread 

LSA = 235 ft2

Benefit category RU

Total 

value RU

Total 

value RU

Total 

value RU

Total 

value

Dollars Dollars Dollars Dollars

Electricity savings ($0.0788/kWh) 66 kWh 5.19 105 kWh 8.30 134 kWh 10.58 66.6 kWh 5.25

Natural gas savings ($0.0110/kBtu) 234 kBtu 2.57 362 kBtu 3.98 428 kBtu 4.71 238 kBtu 2.62

Carbon dioxide ($0.003/lb) 189 lb 0.63 332 lb 1.11 422 lb 1.41 204.7 lb 0.68

Ozone ($0.61/lb) 0.25 lb 0.15 0.40 lb 0.24 0.52 lb 0.32 0.35 lb 0.22

Nitrogen dioxide ($0.61/lb) 0.49 lb 0.30 0.77 lb 0.47 1.06 lb 0.65 0.53 lb 0.33

Sulfur dioxide ($1.42/lb) 0.40 lb 0.57 0.63 lb 0.90 0.87 lb 1.23 0.42 lb 0.60

Small particulate matter ($1.14/lb) 0.25 lb 0.29 0.36 lb 0.42 0.45 lb 0.51 0.30 lb 0.34

Volatile organic compounds ($0.19/lb) 0.09 lb 0.02 0.14 lb 0.03 0.19 lb 0.04 0.09 lb 0.02

Biogenic volatile organic compounds 

($0.19/lb) -1.41 lb - 0.27 -0.24 lb - 0.05 0 lb 0.00 -0.24 lb - 0.05

Rainfall interception ($0.005/gal) 259 gal 1.30 430 gal 2.15 638 gal 3.19 393 gal 1.97

Environmental subtotal 10.74 17.55 22.63 11.97

Other benefits 2.75 11.12 26.44 8.03

Total benefits 13.49 28.68 49.08 20.00

Total costs 7.06 8.78 10.10 9.90

Net benefits 6.43 19.90 38.98 10.10

LSA = leaf surface area; RU = resource unit.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

29

Average Annual Costs

Averaged over 40 years, the costs for yard and public trees, respectively, are as 

follows:

• $7 and $11 for a small tree

• $8 and $13 for a medium tree

• $10 and $17 for a large tree

• $9 and $14 for a conifer

Annualized over the 40-year period, tree planting is the single greatest cost for 

public and yard trees, averaging approximately $4 per tree per year (see app. 2). 

Based on our survey, we assume in this study that a 15-gal yard tree is planted at a 

cost of $150. The cost for planting a 2-in public tree is also $150. For yard trees, the 

next highest expense comes at the end of the tree’s life cycle. Removal and disposal 

costs, annualized over 40 years, average $2 to $3 per tree. Annual expenditures 

for tree pruning are a substantial cost, especially for trees planted in public spaces 

($2 to $6 per tree per year). At $2 to $3 per tree per year, administrative costs are 

significant for public trees.

Table 3 shows annual management costs 20 years after planting for yard trees 

to the west of a house and for public trees. Annual costs for yard trees range from 

$2 to $6, whereas public tree care costs are $7 to $10. In general, public trees 

are more expensive to maintain than yard trees because of their prominence and 

because of the greater need for public safety.

Table 3—Estimated annual costs 20 years after planting for a private tree 

opposite the west-facing wall and a public tree

Goldenrain tree

small tree

20 ft tall

20-ft spread

LSA = 168 ft2

Honeylocust

medium tree

26 ft tall

26-ft spread

LSA = 456 ft2

White ash

large tree

31 ft tall

29-ft spread

LSA = 988 ft2

Ponderosa pine

conifer tree

23 ft tall

20-ft spread

LSA= 235 ft2

Costs

Private: 

west

Public 

tree

Private: 

west

Public 

tree

Private: 

west

Public 

tree

Private: 

west

Public 

tree

Dollars per tree per year

Tree and planting 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Pruning 0.09 1.80 2.77 3.05 2.77 3.05 2.77 3.05

Remove and dispose 2.08 1.74 2.27 1.89 2.79 2.33 2.71 2.27

Infrastructure 0.12 0.95 0.13 1.04 0.16 1.28 0.16 1.24

Cleanup 0.02 0.17 0.02 0.19 0.03 0.23 0.03 0.22

Admin. and other 0 2.38 0 2.60 0 3.20 0 3.11

Total costs 2.31 7.06 5.19 8.78 5.75 10.10 5.66 9.90

Total benefits 15.31 13.49 31.27 28.68 52.57 49.08 21.38 20.00

Total net benefits 13.01 6.43 26.08 19.90 46.82 38.98 15.71 10.10

Note: Prices for removal and disposal are included to account for expected mortality of citywide planting.

LSA = leaf surface area.

Costs of tree care
30

GENERAL TECHNICAL REPORT PSW-GTR-205 

Average Annual Benefits

Average annual benefits, including stormwater reduction, aesthetic value, air quality improvement and carbon dioxide (CO2) sequestration increase with mature tree 

size (figs. 18 and 19; for detailed results see app. 2):

• $9 to $14 for a small tree

• $26 to $33 for a medium tree

• $69 to $78 for a large tree

• $20 to $29 for a conifer

Energy savings—

Trees provide significant energy benefits that increase with tree size. For example, 

average annual net energy benefits over the 40-year period are $9 for the small 

goldenrain tree opposite a west-facing wall, and $28 for the larger white ash. 

Average annual net energy benefits for public trees are less than for yard trees 

because public trees are assumed to provide general climate effects, but not to 

shade buildings directly. Energy benefits for public trees range from $7 for the 

goldenrain to $21 for the white ash. For species of all sizes, energy savings increase 

as trees mature and their leaf surface area increases (figs. 18 and 19). 

As expected in a region with hot, dry summers and milder winters, cooling savings account for most of the total energy benefit. Average annual cooling savings 

over the 40-year period for the small tree range from $5 to $8, but the densely 

branched, low-limbed goldenrain tree may have a negative effect on heating costs, 

depending on planting location. When planted on the east or west sides of a house, 

the goldenrain tree has a small positive average effect on heating costs ($1), but 

planted on the southern side of a house, it has an average negative effect of -$1, 

because it blocks the warm southern rays of the winter sun (see also fig. 4). The 

same is true for the ponderosa pine planted on the southern side of a house (-$4). 

Public goldenrain trees and ponderosa pines have a positive winter climate effect 

because they slow winter winds without shading buildings; they are valued at $2 

and $3, respectively.

Forty years after planting, average annual energy savings for a yard tree opposite a west wall are $12, $26, $57, and $20, respectively, for the small, medium, and 

large deciduous trees and the conifer.

Average annual net energy benefits for residential trees are similar for trees 

located west and east of a building. Cooling savings owing to tree shade are comparable for east and west trees, but trees located east of a building slightly increase 

heating costs compared to trees to the west owing to greater winter shade. A yard 

Energy benefits are 

crucial
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

31

Figure 18—Estimated annual benefits and costs for a small 

(goldenrain tree), medium (honeylocust), and large (white 

ash) deciduous tree, and a conifer (ponderosa pine) located 

west of a residence. Costs are greatest during the initial 

establishment period, and benefits increase with tree size.

Figure 19—Estimated annual benefits and costs for public 

small (goldenrain tree), medium (honeylocust), and large 

(white ash) deciduous trees, and a conifer (ponderosa pine).
32

GENERAL TECHNICAL REPORT PSW-GTR-205 

tree located south of a building produces the least net energy benefit because it has 

the least benefit during summer, and the greatest adverse effect on heating costs 

from shade in winter. Net energy benefits also reflect species-related traits such as 

size, form, crown density, and time in leaf.

Aesthetic and other benefits—

Aesthetic and other benefits reflected in property values account for a significant 

portion of total benefits. As trees grow and become more visible, they can increase 

a property’s sales price. Annual values averaged over 40 years associated with 

these aesthetic and other benefits for yard trees are $2, $10, $37, and $12 for the 

small, medium, and large deciduous trees and for the conifer, respectively. The 

values for public trees are $2, $12, $43, and $13, respectively. The values for yard 

trees are slightly less than for public trees because off-street trees contribute less to 

a property’s curb appeal than more prominent street trees. Because our estimates 

are based on median home sale prices, the effects of trees on property values and 

aesthetics will differ depending on local economies. 

Stormwater runoff reduction—

Benefits associated with rainfall interception, reducing stormwater runoff, are 

significant for all tree types. The white ash intercepts 1,245 gal per year on average 

over a 40-year period with an implied value of $6. The goldenrain tree, honeylocust, 

and ponderosa pine intercept 281, 573, and 669 gal per year on average, with values 

of $1, $3, and $3, respectively. Forty years after planting, average stormwater runoff 

reductions equal 487, 1,225, 3,432, and 1,775, respectively, for the small, medium, 

and large deciduous trees and the conifer.

As the cities of the Interior West continue to grow, the amount of impervious 

surface will continue to increase dramatically. The role that trees, in combination 

with other strategies such as rain gardens and structural soils, can play in reducing 

stormwater runoff is substantial. 

Air quality improvement—

Air quality benefits are defined as the sum of pollutant uptake by trees and reduced 

power plant emissions owing to energy savings minus biogenic volatile organic 

compounds (BVOCs) released by trees. Average annual air quality benefits over 

the 40-year period range from $1 to $4 per tree. These relatively low air quality 

benefits reflect the clean air of most cities in the Interior West region, where much 

of the energy is produced from clean sources such as hydroelectric plants. Contrast 

these results with the air quality benefits of a large tree in the Northeast region ($13; 

McPherson et al. [in press]), Midwest region ($7.65; McPherson et al. 2006c), and 

southern California ($28.38; McPherson 2000).

Aesthetic benefits 

are substantial
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

33

The ability of trees to reduce sulfur dioxide (SO2) from the air is the most 

highly valued. The white ash, for example, is estimated to reduce an average of 

more than 1 lb of SO2 from the air annually, valued at $1.73. Average annual reductions in nitrous oxide, ozone, small particulate matter, and volatile organic compounds for the large tree are valued at $0.92, $0.56, $0.77, and $0.05, respectively.

Forty years after planting, the average annual monetary values of air quality 

improvement for the goldenrain tree, honeylocust, white ash, and ponderosa pine 

are $1.44, $3.64, $8.97, and $2.81, respectively.

Carbon dioxide reduction—

Net atmospheric carbon dioxide (CO2) reductions accrue for all tree types. Average 

annual net reductions range from a high of 855 lbs ($3) for a large tree on the west 

side of a house to a low of 151 lbs ($0.50) for a small tree on the southern side of 

the house. Deciduous trees opposite west-facing house walls generally produce the 

greatest CO2 reduction owing to reduced power plant emissions associated with 

energy savings. The values for the goldenrain tree are lowest for CO2 reduction 

because its small leaf area and slow growth mean that it is sequestering little CO2. 

Forty years after planting, average annual reduced emissions and sequestered 

and released CO2 for a yard tree opposite a west wall are 338, 809, 1,783, and 644 

lbs, respectively, for the small, medium, and large deciduous trees and the conifer. 

Releases of CO2 associated with tree care activities account for less than 1 percent 

of net CO2 sequestration.
34

GENERAL TECHNICAL REPORT PSW-GTR-205 
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

35

Chapter 4: Estimating Benefits and Costs for Tree 

Planting Projects in Your Community

This chapter shows two ways that benefit-cost information presented in this guide can 

be used. The first hypothetical example demonstrates how to adjust values from the 

guide for local conditions when the goal is to estimate benefits and costs for a proposed tree planting project. The second example explains how to compare net benefits 

derived from planting different types of trees. The last section discusses actions 

communities can take to increase the cost-effectiveness of their tree programs.

Applying Benefit–Cost Data

Llano Creek Example

The hypothetical city of Llano Creek is located in the Interior West region and 

has a population of 24,000. Most of its street trees were planted decades ago, with 

Siberian elms and cottonwoods (see “Common and Scientific Names” section) as 

the dominant species. Currently, the tree canopy cover is sparse because a number 

of trees died after drought conditions made the trees more susceptible to pests, and 

they have not been replaced. Many of the remaining street trees are in declining 

health. The city hired an urban forester 2 years ago and an active citizens’ group, 

the Green Team, has formed (fig. 20).

Figure 20—The fictional Green 

Team is motivated to regreen their 

community by planting 1,000 trees 

in 5 years.
36

GENERAL TECHNICAL REPORT PSW-GTR-205 

Initial discussions among the Green Team, local utilities, the urban forester, and 

other partners led to a proposed urban forestry program. The program intends to 

plant 1,000 trees in Llano Creek over a 5-year period. Trained volunteers will plant 

2-in diameter trees in the following proportions: 70 percent large-maturing trees, 

15 percent medium-maturing trees, 5 percent small-maturing trees, and 10 percent 

conifers. One hundred trees will be planted in parks, and the remaining 900 trees 

will be planted along Main Street and other downtown streets.

The Llano Creek City Council has agreed to maintain the current funding level 

for management of existing trees. Also, they will advocate formation of a municipal 

tree district to raise funds for the proposed tree-planting project. A municipal tree 

district is similar in concept to a landscape assessment district, which receives revenues based on formulas that account for the services different customers receive. 

For example, the proximity of customers to greenspace in a landscape assessment 

district may determine how much they pay for upkeep. A municipal tree district 

might receive funding from air quality districts, stormwater management agencies, electric utilities, businesses, and residents in proportion to the value of future 

benefits these groups will receive from trees in terms of air quality, hydrology, 

energy, carbon dioxide (CO2), and property value. The formation of such a district 

would require voter approval of a special assessment that charges recipients for 

tree planting and maintenance costs in proportion to the benefits they receive from 

the new trees. The council needs to know the amount of funding required for tree 

planting and maintenance, as well as how the benefits will be distributed over the 

40-year life of the project.

As a first step, the Llano Creek city forester and Green Team decided to use the 

tables in appendix 2 to quantify total cumulative benefits and costs over 40 years 

for the proposed planting of 1,000 public trees—700 large, 150 medium, and 50 

small deciduous trees and 100 conifers. 

Before setting up a spreadsheet to calculate benefits and costs, the team considered which aspects of Llano Creek’s urban and community forestry project differ 

from the regional values used in this guide (the methods for calculating the values 

in app. 2 are described in app. 3):

1. The prices of electricity and natural gas in Cypress Creek are $0.09 per kWh 

and $0.0118 per kBtu, not $0.0788 per kWh and $0.0110 per kBtu as used in this 

guide. It is assumed that the buildings that will be shaded by the new street trees 

have air conditioning and natural-gas heating.

2. The Green Team projected future annual costs for monitoring tree health 

and implementing their stewardship program. Administration costs are estimated 

to average $3,000 annually for the life of the trees or $3.00 per tree each year. This 

The first step: 

determine tree 

planting numbers
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

37

guide assumed an average annual administration cost of $3.21 per tree for large 

public trees. Thus, an adjustment is necessary.

3. Planting will cost $100 per tree. The guide assumes planting costs of $150 

per tree. The costs will be slightly lower for Llano Creek because the labor will be 

provided by trained volunteers. 

To calculate the dollar value of total benefits and costs for the 40-year period, 

the forester created a spreadsheet table (table 4). Each benefit and cost category is 

listed in the first column. Prices, adjusted where necessary for Llano Creek, are 

entered into the second column. The third column contains the resource units (RUs) 

per tree per year associated with the benefit or the cost per tree per year, which can 

be found in appendix 2. For aesthetic and other benefits, the dollar values for public 

trees are placed in the RU columns. The fourth column lists the 40-year total values, obtained by multiplying the RU values by tree numbers, prices, and 40 years. 

To adjust for higher electricity prices, the forester multiplied electricity saved 

for a large public tree in the RU column (204 kWh) by the Llano Creek price for 

electricity ($0.09 per kWh). This value ($18.36 per tree per year) was multiplied by 

the number of trees planted and 40 years ($18.36 × 700 trees × 40 years = $514,080) 

to obtain cumulative air-conditioning energy savings for the large public trees (table 

4). The process was carried out for all benefits and all tree types.

To adjust cost figures, the city forester changed the planting cost from $150 

assumed in the guide to $100 (table 4). This planting cost was annualized by dividing the cost per tree by 40 years ($100/40 = $2.50 per tree per year). Total planting 

costs were calculated by multiplying this value by 700 large trees and 40 years 

($70,000). 

The administration, inspection, and outreach costs are expected to average 

$3.00 per tree per year. Consequently, the total administration cost for large trees is 

$3.00 × 700 large trees × 40 years ($84,000). The same procedure was followed to 

calculate costs for the medium and small trees and conifers.

All costs and all benefits were summed. Annual benefits over 40 years for the 

whole planting total $2.56 million ($63.99 per tree per year), and annual costs total 

about $580,000 ($14.49 per tree per year). Subtracting total costs from total benefits 

yields net benefits over the 40-year period: 

• $5,127 or $2.57 per tree per year for small deciduous trees

• $122,254 or $20.38 per tree per year for medium deciduous trees

• $1,788,561 or $63.88 per tree per year for large deciduous trees

• $64,096 or $16.02 per tree per year for conifers

The second step: 

adjust for local 

prices of benefits

The third step: adjust 

for local costs

The fourth step: 

calculate net benefits 

and benefit-cost 

ratios for public trees
38

GENERAL TECHNICAL REPORT PSW-GTR-205 

Table 4—Spreadsheet calculations of benefits and costs for the Llano Creek planting project (1,000 trees) over 40 years Benefits Adjusted price 50 small trees 150 medium trees 700 large trees 100 conifer trees 1,000 total trees Percentage of benefits Total value Total value Total value Total value Total value Dollars RU/tree/yr Dollars RU/tree/yr Dollars RU/tree/yr Dollars RU/tree/yr Dollars Dollars $/tree/yr Electricity (kWh) 0.09 61 10,980 114 61,560 204 514,080 74 26,640 613,260 15.33 24 Natural gas (kBtu) 0.0118 214 5,050 361 25,559 491 162,226 250 11,800 204,635 5.12 8 Net carbon dioxide (lb) 0.0033 174 1,148 318 6,296 628 58,027 234 3,089 68,560 1.71 3 Ozone (lb) 0.6102 0.26 317 0.48 1,757 0.92 15,719 0.45 1,098 18,891 0.47 1 Nitrogen dioxide (lb) 0.61 0.45 549 0.84 3,074 1.51 25,791 0.61 1,488 30,902 0.77 1 Sulfur dioxide (lb) 1.42 0.37 1,051 0.68 5,794 1.22 48,507 0.48 2,726 58,078 1.45 2 Small particulate matter (lb) 1.14 0.20 456 0.43 2,941 0.67 21,386 0.40 1,824 26,607 0.67 1 Volatile organic compounds (lb) 0.19 0.08 30 0.15 171 0.26 1,383 0.10 76 1,660 0.04 0 Biogenic volatile organic compounds (lb) 0.19 -0.93 -353 -0.59 -673 0.00 0 -1.28 -973 -1,999 -0.05 0 Hydrology (gal) 0.005 281 2,810 573 17,190 1,245 174,300 669 13,380 207,680 5.19 8 Aesthetics and other 2.18 4,360 11.64 69,840 42.99 1,203,720 13.33 53,320 1,331,240 33.28 52 Total benefits 26,398 193,509 2,225,139 114,468 2,559,514 63.99 Costs Percentage of costs $/tree/yr Dollars $/tree/yr Dollars $/tree/yr Dollars $/tree/yr Dollars Dollars $/tree/yr Tree and planting 2.5 5,000 2.50 15,000 2.50 70,000 2.50 10,000 100,000 2.50 17 Pruning 2.33 4,658 3.03 18,179 5.80 162,528 3.32 13,280 198,646 4.97 34 Remove and dispose 1.70 3,400 2.05 12,293 2.66 74,360 2.39 9,567 99,621 2.49 17 Infrastructure repair 0.84 1,678 1.00 6,002 1.28 35,954 1.17 4,682 48,316 1.21 8 Irrigation 0.12 233 0.12 700 0.12 3,265 0.00 0 4,197 0.10 1 Cleanup 0.15 302 0.18 1,080 0.23 6,472 0.21 843 8,697 0.22 2 Admin. and other 3.00 6,000 3.00 18,000 3.00 84,000 3.00 12,000 120,000 3.00 21 Total costs 21,271 71,255 436,578 50,372 579,476 14.49 Net benefit 5,134 121,973 1,787,738 64,163 1,979,008 49.48 Benefit/cost ratio 1.24 2.71 5.09 2.27 4.42 RU = resource unit.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

39

Dividing total benefits by total costs yielded benefit-cost ratios (BCRs) that 

ranged from 1.24 for small trees, to 2.72, 5.10, and 2.27 for medium and large 

deciduous trees and conifers. The BCR for the entire planting is 4.42, indicating 

that $4.42 will be returned for every $1 invested.

This analysis assumes 45 percent of the planted trees die and does not account 

for the time value of money from a capital investment perspective. Use the municipal discount rate to compare this investment in tree planting and management with 

alternative municipal investments.

The city forester and Green Team now know that the project will cost about 

$580,000, and the average annual cost will be $14,500 ($580,000/40 years); however, a higher proportion of funds will be needed initially for planting and irrigation. The fifth and last step is to identify the distribution of functional benefits that 

the trees will provide. The last column in table 4 shows the distribution of benefits 

as a percentage of the total:

• Energy savings = 32 percent (cooling = 24 percent, heating = 8 percent)

• Carbon dioxide reduction = 3 percent

• Stormwater runoff reduction = 8 percent

• Air quality improvement = 5 percent

• Aesthetics/property value increase = 52 percent

With this information the planning team can determine how to distribute the 

costs for tree planting and maintenance based on who benefits from the services 

the trees will provide. For example, assuming the goal is to generate enough annual 

revenue to cover the total costs of managing the trees ($580,000), fees could be 

distributed in the following manner: 

• $185,600 from electric and natural gas utilities for peak energy savings (29 

percent). (It is more cost effective for utility companies to plant trees to reduce 

peak energy demand than to meet peak needs through added infrastructure.)

• $17,400 from local industry for atmospheric CO2 reductions (2 percent).

• $46,400 from the stormwater management district for water quality improvement associated with reduced runoff (7 percent).

• $29,000 from air quality management district for net reduction in air pollutants 

(5 percent).

• $301,600 from property owners for increased property values (57 percent).

Whether funds are sought from partners, the general fund, or other sources, 

this information can assist managers in developing policy, setting priorities, and 

making decisions. The Center for Urban Forest Research has developed a computer 

The final step: 

determine how 

benefits are 

distributed, and link 

these to sources of 

revenue

Distributing costs of 

tree management to 

multiple parties
40

GENERAL TECHNICAL REPORT PSW-GTR-205 

program called STRATUM that simplifies these calculations for analysis of existing street tree populations (Maco and McPherson 2003; for more information, see 

USDA FS 2007). 

City of Salsola Example

As a municipal cost-cutting measure, the hypothetical city of Salsola plans to 

stop planting street trees in areas of new development. Instead, developers will be 

required to plant front yard trees, thereby reducing costs to the city. The community forester and concerned citizens believe that, although this policy will result in 

lower planting costs, developers may plant smaller trees than the city would have. 

Currently, Salsola’s policy is to plant as large a tree as possible based on each site’s 

available growing space (fig. 21). Planting smaller trees could result in benefits 

“forgone” that will exceed cost savings. To evaluate this possible outcome the 

community forester and concerned citizens decided to compare costs and benefits 

of planting small, medium, and large trees for a hypothetical street-tree planting 

project in Salsola.

Figure 21— Salsola’s policy to 

plant as large a tree as the site 

will handle has provided ample 

benefits in the past. Here, largegrowing trees have been planted.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

41

As a first step, the city forester and concerned citizens decided to quantify the 

total cumulative benefits and costs over 40 years for a typical street tree planting 

of 1,500 trees in Salsola. For comparison purposes, the planting includes 500 small 

trees, 500 medium trees, and 500 large trees. Data in appendix 2 are used for the 

calculations; however, three aspects of Salsola’s urban and community forestry 

program are different than assumed in this tree guide: 

1. The price of electricity is $0.10 per kWh, not $0.0788 per kWh. 

2. The city will provide irrigation for the first 5 years at a cost of approximately 

$0.50 per tree annually.

3. Planting costs are $200 per tree for city trees instead of $150 per tree.

To calculate the dollar value of total benefits and costs for the 40-year period, 

the last column in appendix 2 (40-year average) is multiplied by 40 years. Since 

this value is for one tree, it must be multiplied by the total number of trees planted 

in the respective small, medium, or large tree size classes. To adjust for higher 

electricity prices, we multiply electricity saved for each tree type in the RU column 

by the number of trees and 40 years (large tree: 204 kWh × 500 trees × 40 years 

= 4,080,000 kWh). This value is multiplied by the price of electricity in Salsola 

($0.010/kWh × 4,080,000 kWh = $408,000) to obtain cumulative air-conditioning 

energy savings for the project (table 5). 

All the benefits are summed for each size tree for a 40-year period. The 500 

small trees provide $276,400 in total benefits. The medium and large trees provide 

approximately $670,400 and $1.6 million, respectively.

To adjust cost figures, we add a value for irrigation by multiplying the 

annual cost by the number of trees by the number of years that irrigation will be 

applied ($0.50 × 500 trees × 5 years = $1,250). We multiply 500 large trees by the 

unit planting cost ($200) to obtain the adjusted cost for planting (500 × $200 = 

$100,000). The average annual 40-year costs taken from appendix 2 for other items 

are multiplied by 40 years and the appropriate number of trees to compute total 

costs. These 40-year cost values are entered into table 5. The total costs for the 

small, medium and large trees are $243,650, $276,450, and $364,850. 

Subtracting total costs from total benefits yields net benefits for the small 

($32,750), medium ($393,950), and large ($1,265,550) trees. The total net benefits for 

the 40-year period are $1.7 million (total benefits × total costs), or $1,128 per tree 

($1.7 million/1,500 trees) on average (table 5).

The net benefits per public tree planted are as follows:

• $66 for a small tree

• $788 for a medium tree

• $2,531 for a large tree

The third step: adjust 

for local costs

The first step: 

calculate benefits 

and costs over 40 

years

The second step: 

adjust for local 

prices of benefits
42

GENERAL TECHNICAL REPORT PSW-GTR-205 

By not investing in street tree planting, the city would save $300,000 in initial 

planting costs. If the developer planted 1,500 small trees, benefits would total 

$829,200 (3 × $276,400 for 500 small trees). If 1,500 large trees were planted, 

benefits would total $4.9 million. Planting all small trees causes the city to forgo 

benefits valued at $4.1 million. This amount far exceeds the savings of $300,000 

obtained by requiring developers to plant new street trees, and suggests that, when 

turning over the responsibility for tree planting to others, the city would benefit by 

developing and enforcing a street tree ordinance that requires planting large trees 

where feasible. 

Based on this analysis, the City of Salsola decided to retain the policy of 

promoting planting of large trees where space permits and require tree shade plans 

that show how developers will achieve 50 percent shade over streets, sidewalks, and 

parking lots within 15 years of development. 

The fourth step: 

calculate cost 

savings and 

benefits foregone

Table 5—Spreadsheet calculations of benefits and costs for the Salsola planting project (1,500 trees) over 40 years

Benefits

500 small 500 medium 500 large 1,500 tree total

RU

Total 

value RU

Total 

value RU

Total 

value RU

Total 

value

Average 

value

Dollars Dollars Dollars Dollars Dollars/tree

Electricity (kWh) 1,220,000 122,000 2,280,000 228,000 4,080,000 408,000 7,580,000 758,000 505.33

Natural gas (kBtu) 4,280,000 50,200 7,220,000 84,800 9,820,000 115,400 21,320,000 250,400 166.93

Net carbon dioxide (lb) 3,480,000 11,600 7,260,000 24,200 12,560,000 42,000 23,300,000 77,800 51.87

Ozone (lb) 5,110 3,200 9,630 5,800 18,430 11,200 33,170 20,200 13.47

Nitrogen dioxide (lb) 9,100 5,600 16,700 10,200 30,130 18,400 55,930 34,200 22.80

Sulfur dioxide (lb) 7,450 10,600 13,520 19,200 24,350 34,600 45,320 64,400 42.93

Small particulate 

matter (lb) 3,940 4,600 8,640 9,800 13,400 15,400 25,980 29,800 19.87

Volatile organic 

compounds (lb) 1,590 400 2,900 600 5,210 1,000 9,700 2,000 1.33

Biogenic volatile 

organic compounds (lb) -18,630 -3,600 -11,740 -2,200 0 0 -30,370 -5,800 -3.87

Hydrology (gal) 5,620,000 28,200 11,460,000 57,200 24,900,000 124,600 41,980,000 210,000 140.00

Aesthetics and other 

benefits 43,600 232,800 859,800 1,136,200 757.47

Total benefits 276,400 670,400 1,630,400 2,577,200 1,718.00

Costs 

Tree and planting 100,000 100,000 100,000 300,000 200.00

Pruning 46,600 60,600 116,000 223,200 148.80

Remove and dispose 34,000 41,000 53,200 128,200 85.47

Infrastructure 16,800 20,000 25,600 62,400 41.60

Irrigation 1,250 1,250 1,250 3,750 2.50

Cleanup 3,000 3,600 4,600 11,200 7.47

Admin. and other 42,000 50,000 64,200 156,200 104.13

Total costs 243,650 276,450 364,850 884,950 589.97

Net benefits 32,750 393,950 1,265,550 1,692,250 1,128.17

Benefit /cost ratio 1.13 2.43 4.47 2.91

RU = resource unit.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

43

This analysis assumed 45 percent of the planted trees died. It did not account 

for the time value of money from a capital investment perspective, but this could be 

done by using the municipal discount rate.

Increasing Program Cost-Effectiveness

What if the program you have designed is promising in terms of stormwater-runoff 

reduction, energy savings, volunteer participation, and additional benefits, but the 

costs are too high? This section describes some steps to consider that may increase 

benefits and reduce costs, thereby increasing cost-effectiveness.

Increasing Benefits

Improved stewardship to increase the health and survival of recently planted trees 

is one strategy for increasing cost-effectiveness. An evaluation of the Sacramento 

Shade program found that tree survival rates had a substantial impact on projected 

benefits (Hildebrandt et al. 1996). Higher survival rates increase energy savings and 

reduce tree removal and planting costs. 

Conifers and broadleaf evergreens intercept rainfall and particulate matter year 

round as well as reduce windspeeds and provide shade, which lowers summer-cooling and winter-heating costs. Locating these types of trees in yards, parks, school 

grounds, and other open-space areas can increase benefits. 

Energy benefits can be increased further by planting a higher percentage 

of trees in locations that produce the greatest energy savings, such as opposite 

west-facing walls and close to buildings with air conditioning. Keep in mind that 

evergreen trees, as demonstrated in this study by the ponderosa pine, should not be 

planted on the southern side of buildings because their branches and leaves block 

the warm rays of the winter sun. By customizing tree locations to increase numbers 

in high-yield sites, energy savings can be boosted. 

Reducing Program Costs

Cost effectiveness is influenced by program costs as well as benefits:

Cost effectiveness = Total benefit / total program cost

Cutting costs is one strategy to increase cost effectiveness. A substantial 

percentage of total program costs occur during the first 5 years and are associated 

with tree planting and establishment (McPherson 1993). Some strategies to reduce 

these costs include: 

• Plant bare-root or smaller tree stock.

• Use trained volunteers for planting and pruning of young trees (fig. 22).

What if costs are too 

high?

Work to increase 

survival rates

Target tree plantings 

with highest return

Customize planting 

locations

Reduce up-front and 

establishment costs
44

GENERAL TECHNICAL REPORT PSW-GTR-205 

• Provide followup care to increase tree survival and reduce replacement costs.

• Select and locate trees to avoid conflicts with infrastructure.

Where growing conditions are likely to be favorable, such as yard or garden 

settings, it may be cost effective to use smaller, less expensive stock or bare-root 

trees. In highly urbanized settings and sites subject to vandalism, however, large 

stock may survive the initial establishment period better than small stock.

Investing in the resources needed to promote tree establishment during the first 

5 years after planting is usually worthwhile, because once trees are established they 

have a high probability of continued survival. If your program has targeted trees on 

private property, then encourage residents to attend tree-care workshops. Develop 

standards of “establishment success” for different types of tree species. Perform 

periodic inspections to alert residents to tree health problems, and reward those 

whose trees meet your program’s establishment standards. Replace dead trees as 

soon as possible, and identify ways to improve survivability.

Although organizing and training volunteers requires labor and resources, it 

is usually less costly than contracting the work, and it can help build more support 

Figure 22—Trained volunteers 

can plant and maintain young 

trees, allowing the community 

to accomplish more at less cost 

and providing satisfaction for 

participants. (Photo courtesy 

of Tree Trust)

Use less expensive 

stock where 

appropriate

Prune early
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

45

for your program. A cadre of trained volunteers can easily maintain trees until they 

reach a height of about 20 ft and limbs are too high to prune from the ground with 

pole pruners. By the time trees reach this size they are well established. Pruning 

during this establishment period should result in trees that will require less care in 

the long term. Training young trees can provide a strong branching structure that 

requires less frequent thinning and shaping (Costello 2000). Ideally, young trees 

should be inspected and pruned every other year for the first 5 years after planting.

As trees grow larger, pruning costs may increase on a per-tree basis. The 

frequency of pruning will influence these costs, as it takes longer to prune a tree 

that has not been pruned in 10 years than one that was pruned a few years ago. 

Although pruning frequency differs by species and location, a return frequency of 

about 5 to 8 years is usually sufficient for older trees (Miller 1997).

Carefully select and locate trees to avoid conflicts with overhead power 

lines, sidewalks, and underground utilities. Time spent planning the planting 

will result in long-term savings. Also consider soil type and irrigation, microclimate, and the type of activities occurring around the tree that will influence its 

growth and management. 

When evaluating the bottom line—trees pay us back—do not forget to consider 

benefits other than the stormwater-runoff reductions, energy savings, atmospheric 

CO2 reductions, and other tangible benefits. The magnitude of benefits related to 

employment opportunities, job training, community building, reduced violence, 

and enhanced human health and well-being can be substantial (fig. 23). Moreover, 

these benefits extend beyond the site where trees are planted, furthering collaborative efforts to build better communities. 

For more information on urban and community forestry program design and 

implementation, see the list of additional resources in appendix 1.

Match tree to site

It all adds up—trees 

pay us back

Figure 23—Trees pay us back in tangible and 

intangible ways.
46

GENERAL TECHNICAL REPORT PSW-GTR-205 
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

47

Chapter 5: General Guidelines for Selecting and 

Placing Trees

Guidelines for Energy Savings

Maximizing Energy Savings From Shading

The right tree in the right place can save energy and reduce tree care costs. In 

midsummer, the sun shines on the east side of a building in the morning, passes 

over the roof near midday, and then shines on the west side in the afternoon (see 

fig. 4). Electricity use is highest during the afternoon when temperatures are 

warmest and incoming sunshine is greatest. Therefore, the west side of a home is 

the most important side to shade (Sand 1993; fig. 24). 

Depending on building orientation and window placement, sun shining through 

windows can heat a home quickly during the morning hours. The east side is the 

second most important side to shade when considering the net impact of tree shade 

on energy savings (fig. 24). Deciduous trees on the east side provide summer shade 

and more winter solar heat gain than evergreens.

Trees located to shade south walls can block winter sunshine and increase 

heating costs because during winter the sun is lower in the sky and shines on 

the south side of homes (fig. 25). The warmth the sun provides is an asset, and 

planting evergreen trees on the southern side of a house would block southern 

exposures and solar collectors. Use solar-friendly trees to the south because the 

bare branches of these deciduous trees allow most sunlight to strike the building 

(some solar-unfriendly deciduous trees can reduce sunlight striking the south 

side of buildings by 50 percent even without leaves) (Ames 1987). Examples of 

solar-friendly trees include most species and cultivars of maples, crapemyrtle, 

honeylocust, sweetgum, and zelkova (see “Common and Scientific Names” 

Figure 24—Locate trees to shade west and east 

windows (from Sand 1993).

Figure 25—Select solar-friendly trees for 

southern exposures and locate them close 

enough to provide winter solar access and 

summer shade (from Sand 1991).

Where should shade 

trees be planted?
48

GENERAL TECHNICAL REPORT PSW-GTR-205 

section). Some solar-unfriendly trees include most oaks, sycamore, most elms, 

and river birch (McPherson et al. 1994).

To maximize summer shade and minimize winter shade, locate shade trees 

about 10 to 20 ft south of the home. As trees grow taller, prune lower branches to 

allow more sun to reach the building if this will not weaken the tree’s structure 

(fig. 26).

Although the closer a tree is to a home the more shade it provides, roots of trees 

that are too close can damage the foundation. Branches that impinge on the building 

can make it difficult to maintain exterior walls and windows. Keep trees 10 ft or 

farther from the home depending on mature crown spread, to avoid these conflicts. 

Trees within 30 to 50 ft of the home most effectively shade windows and walls.

Paved patios and driveways can become heat sinks that warm the home during 

the day. Shade trees can make them cooler and more comfortable spaces. If a home 

is equipped with an air conditioner, shading can reduce its energy use, but do not 

plant vegetation so close that it will obstruct the flow of air around the unit.

Plant only small-growing trees under overhead power lines, and avoid planting 

directly above underground water and sewer lines if possible. Contact your local 

utility company before planting to determine where underground lines are located 

and which tree species should not be planted below power lines.

Figure 26—Trees south of a home before and 

after pruning. Lower branches are pruned up 

to increase heat gain from winter sunlight 

(from Sand 1993).
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

49

Planting Windbreaks for Heating Savings

A tree’s size and crown density can make it ideal for blocking wind, thereby reducing the impacts of cold winter weather. Locate rows of trees perpendicular to the 

prevailing wind (fig. 27), usually the north and west side of homes in the Interior 

West region.

Design the windbreak row to be longer than the building being sheltered 

because windspeed increases at the edge of the windbreak. Ideally, the windbreak 

should be planted upwind about 25 to 50 ft from the building and should consist 

of dense evergreens that will grow to twice the height of the building they shelter 

(Heisler 1986, Sand 1991). Avoid planting windbreaks that will block sunlight 

to south and east walls (fig. 28). Trees should be spaced close enough to form a 

dense screen, but not so close that they will block sunlight to each other, causing 

lower branches to self-prune. Most conifers can be spaced about 6 ft on center. If 

there is room for two or more rows, then space rows 10 to 12 ft apart. 

Evergreens are preferred over deciduous trees for windbreaks because they 

provide better wind protection. The ideal windbreak tree is fast growing, visually 

dense, has strong branch attachments, and has stiff branches that do not self-prune. 

Your local cooperative extension agent or urban forester can help you select appropriate trees for your area.

In settings where vegetation is not a fire hazard, evergreens planted close to 

the home create airspaces that reduce air infiltration and heat loss. Allow shrubs to 

form thick hedges, especially along north, west, and east walls.

Figure 27—Evergreens protect a building from dust and cold by 

reducing windspeeds (from Sand 1993).

Figure 28—Mid-winter shadows from a well-located 

windbreak and shade trees do not block solar radiation on the 

south-facing wall (from Sand 1993).

Plant dense 

evergreens
50

GENERAL TECHNICAL REPORT PSW-GTR-205 

Selecting Trees to Maximize Benefits

The ideal shade tree has a fairly dense, round crown with limbs broad enough 

to partially shade the roof. Given the same placement, a large tree will provide 

more shade than a small tree. Deciduous trees allow sun to shine through leafless branches in winter. Plant small trees where nearby buildings or power lines 

limit aboveground space. Columnar trees are appropriate in narrow side yards. 

Because the best location for shade trees is relatively close to the west and east 

sides of buildings, the most suitable trees will be strong and capable of resisting 

storm damage, disease, and pests (Sand 1994). Examples of trees not to select for 

placement near buildings include cottonwoods and silver maple because of their 

invasive roots, weak wood, and large size, and ginkgos because of their sparse 

shade and slow growth. 

When selecting trees, match the tree’s water requirements with those of surrounding plants. For instance, select low water-use species for planting in areas 

that receive little irrigation. Also, match the tree’s maintenance requirements with 

the amount of care and the type of use different areas in the landscape receive. For 

instance, tree species that drop fruit that can be a slip-and-fall problem should not 

be planted near paved areas that are frequently used by pedestrians. Check with 

your local landscape professional before selecting trees to make sure that they are 

well suited to the site’s soil and climatic conditions. 

Use the following practices to plant and manage trees strategically to maximize 

energy conservation benefits: 

• Increase community-wide tree canopy, and target shade to streets, parking lots, 

and other paved surfaces, as well as air-conditioned buildings.

• Shade west- and east-facing windows and walls.

• Avoid planting trees to the south of buildings.

• Select solar-friendly trees opposite east- and south-facing walls.

• Shade air conditioners, but don’t obstruct airflow.

• Avoid planting trees too close to utilities and buildings.

• Create multirow, evergreen windbreaks where space permits, that are longer 

than the building.

Guidelines for Reducing Carbon Dioxide

Because trees in common areas and other public places may not shelter buildings 

from sun and wind and reduce energy use, carbon dioxide (CO2) reductions are 

primarily from sequestration. Fast-growing trees sequester more CO2 initially 

than slow-growing trees, but this advantage can be lost if the fast-growing trees 

There are many 

choices

Picking the right tree

Maximizing energy 

savings from trees
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

51

die at younger ages. Large trees have the capacity to store more CO2 than smaller 

trees (fig. 29). To maximize CO2 sequestration, select tree species that are well 

suited to the site where they will be planted. Consult with your local arborist to 

select the right tree for your site. Trees that are not well adapted will grow slowly, 

show symptoms of stress, or die at an early age. Unhealthy trees do little to reduce 

atmospheric CO2 and can be unsightly liabilities in the landscape.

Design and management guidelines that can increase CO2 reductions include 

the following:

• Maximize use of woody plants, especially trees, as they store more CO2 than do 

herbaceous plants and grasses.

• Plant more trees where feasible and immediately replace dead trees to compensate for CO2 lost through removal.

• Create diverse habitats, with trees of different ages and species, to promote a 

continuous canopy cover over time.

• Group species with similar landscape maintenance requirements together and 

consider how irrigation, pruning, fertilization, weed, pest, and disease control 

can be minimized.

Figure 29—Compared with small trees, large trees can store more carbon, filter more air pollutants, 

intercept more rainfall, and provide greater energy savings.
52

GENERAL TECHNICAL REPORT PSW-GTR-205 

• Reduce CO2 associated with landscape management by using push mowers (not 

gas or electric), hand saws (not chain saws), pruners (not gas/electric shears), 

rakes (not leaf blowers), and employ landscape professionals who do not have to 

travel far to your site.

• Reduce maintenance by reducing turfgrass and planting drought-tolerant or 

environmentally friendly landscapes. 

• Consider the project’s lifespan when selecting species. Fast-growing species will 

sequester more CO2 initially than slow-growing species, but may not live as long.

• Provide ample space belowground for tree roots to grow so that they can maximize CO2 sequestration and tree longevity.

• When trees die or are removed, salvage as much wood as possible for use as 

furniture and other long-lasting products to delay decomposition.

• Plant trees, shrubs, and vines in strategic locations to maximize summer shade 

and reduce winter shade, thereby reducing atmospheric CO2 emissions associated with power production.

Guidelines for Reducing Stormwater Runoff

Trees are mini-reservoirs, controlling runoff at the source because their leaves and 

branch surfaces intercept and store rainfall, thereby reducing runoff volumes and 

erosion of watercourses, as well as delaying the onset of peak flows. Rainfall interception by large trees is a relatively inexpensive first line of defense in the battle to 

control nonpoint-source pollution.

When selecting trees to maximize rainfall interception benefits, consider 

the following:

• Select tree species with physiological features that maximize interception, such 

as large leaf surface area and rough surfaces that store water (Metro 2002).

• Increase interception by planting large trees where possible (fig. 30).

• Plant trees that are in leaf when precipitation levels are highest.

• Select conifers because they have high interception rates, but avoid shading 

south-facing windows to maximize solar heat gain in winter.

• Plant low-water-use tree species where appropriate and native species that, once 

established, require little supplemental irrigation.

• In bioretention areas, such as roadside swales, select species that tolerate 

inundation, are long-lived, wide-spreading, and fast-growing (Metro 2002).

• Do not pave over streetside planting strips for easier weed control; this can 

reduce tree health and increase runoff.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

53

• Bioswales in parking lots and other paved areas store and filter stormwater 

while providing good conditions for trees.

Guidelines for Improving Air Quality Benefits

Trees, sometimes called the “lungs of our cities,” are important because of their 

ability to remove contaminants from the air. The amount of gaseous pollutants and 

particulates removed by trees depends on their size and architecture, as well as 

local meteorology and pollutant concentrations.

Along streets, in parking lots, and in commercial areas, locate trees to 

maximize shade on paving and parked vehicles. Shade trees reduce heat that is 

stored or reflected by paved surfaces. By cooling streets and parking areas, trees 

reduce emissions of evaporative hydrocarbons from parked cars and thereby 

reduce smog formation (Scott et al. 1999). Large trees can shade a greater area than 

smaller trees, but should be used only where space permits. Remember that a tree 

needs space for both branches and roots.

Tree planting and management guidelines to improve air quality include the 

following (Nowak 2000, Smith and Dochinger 1976):

• Select species that tolerate pollutants that are present in harmful concentrations. For example, in areas with high ozone concentration avoid sensitive 

species such as white and green ash, tulip poplar, and Austrian pine (Noble 

et al. 1988).

• Conifers have high surface-to-volume ratios and retain their foliage year round, 

which may make them more effective than deciduous species.

Figure 30—Trees can create a 

continuous canopy for maximum 

rainfall interception, even in 

commercial areas. In this example, 

a swale in the median filters runoff 

and provides ample space for large 

trees. Parking space-sized planters 

contain the soil volume required 

to grow healthy, large trees (from 

Metro 2002).
54

GENERAL TECHNICAL REPORT PSW-GTR-205 

• Species with long leaf stems (e.g., ash, maple) and hairy plant parts (e.g., oak, 

birch, sumac) are especially efficient interceptors.

• Effective uptake depends on proximity to the pollutant source and the 

amount of biomass. Where space permits, plant multilayered stands near the 

source of pollutants.

• Consider the local meteorology and topography to promote airflow that can 

“flush” pollutants at night and avoid trapping them in the urban canopy layer 

during the day.

• In areas with unhealthy ozone concentrations, maximize use of plants that emit 

low levels of biogenic volatile organic compounds to reduce ozone formation.

• Sustain large, healthy trees; they produce the most benefits.

• To reduce emissions of volatile organic compounds and other pollutants, plant 

trees to shade parked cars and conserve energy.

Guidelines for Avoiding Conflicts With Infrastructure

Trees can become liabilities when they conflict with power lines, underground 

utilities, and other infrastructure elements. Guidelines to reduce conflicts with 

infrastructure include the following:

• Before planting, contact your local before-digging company, such as Call 

Before You Dig, Utility Notification Center, or One Call, to locate underground 

water, sewer, gas, and telecommunications lines. 

• Avoid locating trees where they will block streetlights or views of traffic and 

commercial signs. 

• Check with local transportation officials for sight visibility requirements. Keep 

trees at least 30 ft away from street intersections to ensure visibility. 

• Avoid planting shallow-rooting species near sidewalks, curbs, and paving where 

tree roots can heave pavement if planted too close. Generally, avoid planting 

within 3 ft of pavement, and remember that trunk flare at the base of large 

trees can displace soil and paving for a considerable distance. Consider strategies to reduce damage by tree roots such as meandering sidewalks around trees 

(Costello and Jones 2003). 

• Select only small trees (<25 ft tall) for location under overhead power lines, and 

do not plant directly above underground water and sewer lines (fig. 31). Avoid 

locating trees where they will block illumination from streetlights or views of 

street signs in parking lots, commercial areas, and along streets.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

55

For trees to deliver benefits over the long term, they require enough soil volume 

to grow and remain healthy. Matching tree species to the site’s soil volume can 

reduce sidewalk and curb damage as well. Figure 32 shows recommended soil 

volumes for different sized trees.

Figure 31—Know where power lines and other utility lines are before planting. Under power lines 

use only small-growing trees (“low zone”) and avoid planting directly above underground utilities. 

Larger trees may be planted where space permits (“medium” and “tall zones”) (from ISA 1992).

Figure 32—Developed from several sources by Urban (1992), this graph shows the relationship 

between tree size and required soil volume. For example, a tree with a 16-in diameter at breast 

height and 640 ft2 of crown projection area (area under the dripline) requires 1,000 ft3 of soil (from 

Costello and Jones 2003).
56

GENERAL TECHNICAL REPORT PSW-GTR-205 

Maintenance requirements and public safety concerns influence the type of 

trees selected for public places. The ideal public tree is not susceptible to wind 

damage and branch drop, does not require frequent pruning, produces negligible litter, is deep-rooted, has few serious pest and disease problems, and tolerates a wide 

range of soil conditions, irrigation regimes, and air pollutants. Because relatively 

few trees have all these traits, it is important to match the tree species to the planting site by determining what issues are most important on a case-by-case basis. For 

example, parking-lot trees should be tolerant of hot, dry conditions, have strong 

branch attachments, and be resistant to attacks by pests that leave vehicles covered 

with sticky exudates. Check with your local landscape professional for horticultural 

information on tree traits.

Guidelines for Maximizing Long-Term Benefits

Selecting a tree from the nursery that has a high probability of becoming a healthy, 

trouble-free mature tree is critical to a successful outcome. Therefore, select the 

very best stock at your nursery, and when necessary, reject nursery stock that does 

not meet industry standards.

The health of the tree’s root ball is critical to its ultimate survival. If the tree 

is in a container, check for matted roots by sliding off the container. Roots should 

penetrate to the edge of the root ball, but not densely circle the inside of the 

container or grow through drain holes. As well, at least two large structural roots 

should emerge from the trunk within 1 to 3 in of the soil surface. If there are no 

roots in the upper portion of the root ball, it is undersized and the tree should not 

be planted.

Another way to evaluate the quality of the tree before planting is to gently move 

the trunk back and forth. A good tree trunk bends and does not move in the soil, 

while a poor trunk bends a little and pivots at or below the soil line—a telltale sign 

of a poorly anchored tree.

Dig the planting hole 1 in shallower than the depth of the root ball to allow for 

some settling after watering. Make the hole two to three times as wide as the root 

ball and loosen the sides of the hole to make it easier for roots to penetrate. Place 

the tree so that the root flare is at the top of the soil. If the structural roots have 

grown properly as described above, the top of the root ball will be slightly higher 

(1 to 2 in) than the surrounding soil to allow for settling. Backfill with the native 

soil unless it is very rocky or sandy, in which case you may want to add composted 

organic matter such as peat moss or shredded bark (fig. 33). 

Planting trees in urban plazas, commercial areas, and parking lots poses special 

challenges owing to limited soil volume and poor soil structure. Engineered or 

Plant the tree in the 

right size hole
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

57

structural soils can be placed under the hardscape to increase rooting space while 

meeting engineering requirements. For more information on structural soils see 

Reducing Infrastructure Damage by Tree Roots: A Compendium of Strategies

(Costello and Jones 2003). 

Use the extra soil left after planting to build a berm outside the root ball that is 6 

in high and 3 ft in diameter. Soak the tree, and gently rock it to settle it in. Cover the 

basin with a 2- to 4-in layer of mulch, but avoid placing mulch against the tree trunk. 

Water the new tree three times a week and increase the amount of water as the tree 

grows larger. Generally, a tree requires about 1 in of water per week, though in areas 

of the interior West this number may be higher. A rain gauge or soil moisture sensor 

(tensiometer) can help determine tree watering needs, or contact your local cooperative extension agent or water conservancy district for recommendations.

After you’ve planted your tree, remember the following:

• Inspect your tree several times a year, and contact a local landscape professional if problems develop. 

• If your tree needed staking to keep it upright, remove the stake and ties after 

1 year or as soon as the tree can hold itself up. The staking should allow some 

tree movement, as this movement sends hormones to the roots causing them to 

grow and create greater tree stability. It also promotes trunk taper and growth. 

• Reapply mulch and irrigate the tree as needed. 

Figure 33—Prepare a broad planting area, plant the tree with the root flare at ground level, 

and provide a berm/water ring to retain water (drawing courtesy of the International Society of 

Arboriculture).
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GENERAL TECHNICAL REPORT PSW-GTR-205 

• Leave lower side branches on young trees for the first year and prune back to 4 

to 6 in to accelerate tree diameter development. Remove these lateral branches 

after the first full year. Prune the young tree to maintain a central main trunk 

and equally spaced branches. For more information, see Costello (2000) and 

Gilman (2002). As the tree matures, have it pruned on a regular basis by a certified arborist or other experienced professional. 

• By keeping your tree healthy, you maximize its ability to produce shade, intercept rainfall, reduce atmospheric CO2, and provide other benefits. 

For more information on tree selection, planting, establishment, and care see 

the resources listed in appendix 1.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

59

Glossary

annual fuel utilization efficiency (AFUE)—A measure of space heating equipment efficiency defined as the fraction of energy output per energy input.

anthropogenic—Produced by humans.

biodiversity—The variety of life forms in a given area. Diversity can be categorized in terms of the number of species, the variety in the area’s plant and animal 

communities, the genetic variability of the animals or plants, or a combination of 

these elements.

biogenic—Produced by living organisms.

biogenic volatile organic compounds (BVOCs)—Hydrocarbon compounds from 

vegetation (e.g., isoprene, monoterpene) that exist in the ambient air and contribute 

to the formation of smog or may themselves be toxic. Emission rates (μg·g-1·hr-1) 

used for this report follow Benjamin and Winer (1998):

• Goldenrain tree (Koelreuteria paniculata)—50.9 (isoprene); 0.0 (monoterpene)

• Honeylocust (Gleditsia triacanthos)—1.6 (isoprene); 2.9 (monoterpene)

• White ash (Fraxinus americana)—0.0 (isoprene); 0.0 (monoterpene)

• Ponderosa pine (Pinus ponderosa)—0.0 (isoprene); 2.3 (monoterpene)

canopy—A layer or multiple layers of branches and foliage at the top or crown of a 

forest’s trees.

canopy cover—The area of land surface that is covered by tree canopy, as seen 

from above. 

Ccf—One hundred cubic feet.

climate—The average weather for a particular region and period (usually 30 years). 

Weather describes the short-term state of the atmosphere; climate is the average 

pattern of weather for a particular region. Climatic elements include precipitation, 

temperature, humidity, sunshine, wind velocity, phenomena such as fog, frost, and 

hailstorms, and other measures of weather.

climate effects—Impact on residential space heating and cooling (kg of CO2

per tree per year) from trees located more than 50 ft from a building owing to 

associated reductions in windspeeds and summer air temperatures. 

community forests—The sum of all woody and associated vegetation in and around 

human settlements, ranging from small rural villages to metropolitan regions.
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GENERAL TECHNICAL REPORT PSW-GTR-205 

contract rate—The percentage of residential trees cared for by commercial arborists; the proportion of trees for which a specific service 

(e.g., pruning or pest management) is contracted.

control costs—The marginal cost of preventing, controlling, or mitigating an impact.

crown—The branches and foliage at the top of a tree.

cultivar (derived from “cultivated variety”)—Denotes certain 

cultivated plants that are clearly distinguishable from others by any 

characteristic, and that when reproduced (sexually or asexually), 

retain their distinguishing characteristics. In the United States, variety

is often considered synonymous with cultivar.

damage costs—The total estimated economic loss produced by an 

impact.

deciduous—Trees or shrubs that lose their leaves every fall.

diameter at breast height (d.b.h.)—The diameter of a tree outside 

the bark measured 4.5 ft above the ground on the uphill side (where 

applicable) of the tree.

dripline—The area beneath a tree marked by the outer edges of the 

branches.

emission factor—The rate of CO2, nitrous oxide (NO2), sulfur dioxide 

(SO2), and small particulate matter (PM10) output resulting from the 

consumption of electricity, natural gas, or any other fuel source.

evapotranspiration (ET)—The total loss of water by evaporation from 

the soil surface and by transpiration from plants, from a given area, and 

during a specified period.

evergreens—Trees or shrubs that are never entirely leafless. Evergreens may be broadleaved or coniferous (cone-bearing with needlelike leaves).

greenspace—Urban trees, forests, and associated vegetation in and 

around human settlements, ranging from small communities in rural 

settings to metropolitan regions.

hardscape—Paving and other impervious ground surfaces that 

reduce infiltration of water into the soil.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

61

heat sinks—Paving, buildings, and other surfaces that store heat energy from the sun.

hourly pollutant dry deposition—Removal of gases from the atmosphere by 

direct transfer to natural surfaces and absorption of gases and particles by natural 

surfaces such as vegetation, soil, water, or snow.

interception—Amount of rainfall held on tree leaves and stem surfaces.

kBtu—A unit of work or energy, measured as 1,000 British thermal units. One 

kBtu is equivalent to 0.293 kWh.

kWh (kilowatt-hour)—A unit of work or energy, measured as 1 kW (1,000 watts) 

of power expended for 1 hr. One kWh is equivalent to 3.412 kBtu.

leaf area index (LAI)—Total leaf area per unit area of crown if crown were 

projected in two dimensions.

leaf surface area (LSA)—Measurement of area of one side of a leaf or leaves.

mature tree—A tree that has reached a desired size or age for its intended use. 

Size, age, and economic maturity differ depending on the species, location, 

growing conditions, and intended use.

mature tree size—The approximate size of a tree 40 years after planting.

MBtu—A unit of work or energy, measured as 1,000,000 British thermal units. 

One MBtu is equivalent to 0.293 MWh.

metric tonne—A measure of weight (abbreviated “t”) equal to 1,000,000 grams 

(1,000 kilograms) or 2,205 lbs.

municipal forester—A person who manages public street and/or park trees 

(municipal forestry programs) for the benefit of the community.

MWh (megawatt-hour)—A unit of work or energy, measured as one megawatt 

(1,000,000 watts) of power expended for 1 hr. One MWh is equivalent to 3.412 

MBtu.

nitrogen oxides (oxides of nitrogen, NOx)—A general term for compounds of 

nitric acid (NO), nitrogen dioxide (NO2), and other oxides of nitrogen. Nitrogen 

oxides are typically created during combustion processes and are major contributors to smog formation and acid deposition. NO2 may cause numerous adverse 

human health effects.

ozone (O3)—A strong-smelling, pale blue, reactive toxic chemical gas consisting 

of three oxygen atoms. It is a product of the photochemical process involving the 
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GENERAL TECHNICAL REPORT PSW-GTR-205 

Sun’s energy. Ozone exists in the upper layer of the atmosphere as well as at the 

Earth’s surface. Ozone at the Earth’s surface can cause numerous adverse human 

health effects. It is a major component of smog.

peak flow (or peak runoff)—The maximum rate of runoff at a given point or from a 

given area, during a specific period.

photosynthesis—The process in green plants of converting water and CO2 into 

sugar with light energy; accompanied by the production of oxygen.

PM10 (particulate matter)—Major class of air pollutants consisting of tiny solid or 

liquid particles of soot, dust, smoke, fumes, and mists. The size of the particles (10 

microns or smaller, about 0.0004 in or less) allows them to enter the air sacs (gasexchange region) deep in the lungs where they may be deposited and cause adverse 

health effects. PM10 also reduces visibility.

reduced power plant emissions—Reduced emissions of carbon dioxide (CO2) or 

other pollutants that result from reductions in building energy use owing to the 

moderating effect of trees on climate. Reduced energy use for heating and cooling 

results in reduced demand for electrical energy, which translates into fewer emissions by power plants.

resource unit (RU)—The value used to determine and calculate benefits and costs 

of individual trees. For example, the amount of air conditioning energy saved in 

kWh/year per tree, air-pollutant uptake in pounds per year per tree, or rainfall 

intercepted in gallons per tree per year.

riparian habitats—Narrow strips of land bordering creeks, rivers, lakes, or other 

bodies of water.

seasonal energy efficiency ratio (SEER)—Ratio of cooling output to power 

consumption; kBtu-output/kWh-input as a fraction. It is the Btu of cooling output 

during normal annual usage divided by the total electric energy input in kilowatthours during the same period.

sequestration—Annual net rate that a tree removes CO2 from the atmosphere 

through the processes of photosynthesis and respiration (kg of CO2 per tree per year).

shade coefficient—The percentage of light striking a tree crown that is transmitted 

through gaps in the crown. This is the percentage of light that hits the ground.

shade effects—Impact on residential space heating and cooling (kg of CO2 per tree 

per year) from trees located within 50 ft of a building.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

63

solar-friendly trees—Trees that have characteristics that reduce blocking of winter 

sunlight. According to one numerical ranking system, these traits include open 

crowns during the winter heating season, leaves that fall early and appear late, 

relatively small size, and a slow growth rate (Ames 1987).

stem flow—Amount of rainfall that travels down the tree trunk and onto the ground.

sulfur dioxide (SO2)—A strong-smelling, colorless gas that is formed by the 

combustion of fossil fuels. Powerplants, which may use coal or oil high in sulfur 

content, can be major sources of SO2. Sulfur oxides contribute to the problem of 

acid deposition.

t—See metric tonne.

therm—A unit of heat equal to 100,000 British thermal units (BTUs) or 100 kBtu. 

Also, 1 kBtu is equal to 0.01 therm.

throughfall—Amount of rainfall that falls directly to the ground below the tree 

crown or drips onto the ground from branches and leaves.

transpiration—The loss of water vapor through the stomata of leaves.

tree or canopy cover—Within a specific area, the percentage covered by the 

crown of an individual tree or delimited by the vertical projection of its outermost 

perimeter; small openings in the crown are ignored. Used to express the relative 

importance of individual species within a vegetation community or to express the 

coverage of woody species.

tree litter—Fruit, leaves, twigs, and other debris shed by trees.

tree-related CO2 emissions—CO2 released when growing, planting, and caring 

for trees.

tree surface saturation storage capacity—The maximum volume of water that 

can be stored on a tree’s leaves, stems, and bark. This part of rainfall stored 

on the canopy surface does not contribute to surface runoff during and after a 

rainfall event.

urban heat island—An area in a city where summertime air temperatures are 

3 to 8 °F warmer than temperatures in the surrounding countryside. Urban areas 

are warmer for two reasons: (1) dark construction materials for roofs and asphalt 

absorb solar energy, and (2) few trees, shrubs, or other vegetation provide shade 

and cool the air.
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GENERAL TECHNICAL REPORT PSW-GTR-205 

volatile organic compounds (VOCs)—Hydrocarbon compounds that exist in the 

ambient air. VOCs contribute to the formation of smog or are themselves toxic. 

VOCs often have an odor. Some examples of VOCs are gasoline, alcohol, and the 

solvents used in paints.

willingness to pay—The maximum amount of money an individual would be 

willing to pay for nonmarket, public goods and services provided by environmental 

amenities such as trees and forests rather than do without.

Common and Scientific Names

Common name Scientific name

Plants:

Arborvitae Thuja occidentalis L.

Austrian pine Pinus nigra Arnold

Birch Betula spp.

Black Hills spruce Picea glauca (Moench) Voss var. densata Bailey 

Blackgum Nyssa spp.

Black oak Quercus velutina Lam.

Colorado spruce Picea pungens Engelm.

Cottonwood Populus spp.

Crabapple Malus spp. 

Crapemyrtle Lagerstroemia indica L.

Elm Ulmus spp.

Fir Abies spp.

Ginkgo Ginkgo biloba L.

Goldenrain tree Koelreuteria paniculata Laxm.

Green ash Fraxinus pennsylvanica Marsh.

Hackberry Celtis occidentalis L.

Hackberry Celtis spp.

Honeylocust Gleditsia triacanthos L.

Japanese zelkova Zelkova serrata (Thunb.) Makino

Maple Acer spp.

New Mexico olive Forestiera pubescens Nutt.

Oak Quercus spp.

Pinyon pine Pinus edulis Engelm.

Ponderosa pine Pinus ponderosa P. & C. Lawson

Poplar Populus spp.

Quaking aspen Populus tremuloides Michx.

Red oak Quercus rubra L.

River birch Betula nigra L.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

65

Russian olive Elaeagnus angustifolia

Siberian elm Ulmus pumila L.

Silver maple Acer saccharinum L.

Sumac Rhus spp.

Sweetgum Liquidambar styraciflua L.

Sycamore Platanus spp.

Tree of heaven Ailanthus altissima (P. Mill.) Swingle

Tulip poplar Liriodendron tulipifera L.

White ash Fraxinus americana L.

White fir Abies concolor (Gord. & Glend.) Lindl. ex Hildebr.

Insects:

Asian long-horned beetle Anoplophora glabripennis Motschulsky

Emerald ash borer Agrilus planipennis Fairmaire

Pathogens:

Dutch elm disease Ophiostoma ulmi (Buisman) Nannf. and 

 Ophiostoma novoulmi (Brasier) 

Acknowledgments

A number of people assisted with data collection and provided technical assistance: Jeff Hart, Jay Hart, Matthew Russell (City of Albuquerque, NM, Parks and 

Recreation Department); Bryan Suhr (Supervisor of Arboriculture, University of 

New Mexico); Jason Fink (Geographic Information Systems Department, City of 

Albuquerque, NM); Bob Angstrom (Osuna Nursery); Frank Feather; Greg Ina, 

Jerry Bond, Scott Maco, Jim Jenkins, Aren Dottenwhy (Davey Resource Group); 

George Duda (New Mexico Forestry Division); Stephanie Huang, Christine Yang, 

and Aywon-Anh Nguyen (Center for Urban Forest Research).

Tree care expenditure information was provided by Matt Russell and Jeff Hart 

(City of Albuquerque, NM), Mike Marett (City of Sandy, UT), Joe Archer (City of 

Logan, UT), Brian Getzelman (ArborCare/ArborScape, Salt Lake City, UT), Jeff 

Lehde (Bartlett Tree Company, Austin, TX), Jim Hubbell (Integrated Tree Management, Logan, UT), and Paul Bryan Jones (PBJ Trees, El Prado, NM).

George Duda, Mike Kuhns, and Peter Smith provided helpful reviews of this work. 

Mark Buscaino, George Duda (U&CF Program Coordinator New Mexico 

Forestry Division) and Jay Hart (Parks and Recreation Department, City of 

Albuquerque, NM) provided invaluable support for this project.
66

GENERAL TECHNICAL REPORT PSW-GTR-205 

Metric Equivalents

When you know: Multiply by: To find:

Inches (in) 25.4 Millimeters (mm)

Feet (ft) .305 Meters (m)

Square feet (ft2) .0929 Square meters (m2)

Miles (mi) 1.61 Kilometers (km)

Square miles (mi2) 2.59 Square kilometers (km2)

Gallons (gal) .00378 Cubic meters (m3)

Pounds (lb) .454 Kilograms (kg)

Pounds per square foot (lb/ft2) 4.882 Kilograms per square meter 

 (kg/m2)

Tons (ton) .907 Metric tonne (t)

Thousand British thermal units (kBtu) .293 Kilowatt hours (kWh)

Fahrenheit (°F) .56 and subtract 32 Celsius 

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Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

79

Appendix 1: Additional Resources

Additional information regarding urban and community forestry program design 

and implementation can be obtained from the following sources:

Utilizing Municipal Trees: Ideas From Across the Country by S.M. Bratkovich

Urban Forestry: Planning and Managing Urban Greenspaces by R.W. Miller 

An Introductory Guide to Community and Urban Forestry in Washington, 

Oregon, and California by N.R. Morgan

A Technical Guide to Urban and Community Forestry by N.R. Morgan

Urban Tree Risk Management: A Community Guide to Program Design and 

Implementation edited by J.D. Pokorny

For additional information on tree selection, planting, establishment, and care 

see the following resources:

Alliance for Community Trees: http://actrees.org

How to Prune Trees by P.J. Bedker, J.G. O’Brien, and M.E. Mielke

Training Young Trees for Structure and Form, a video by L.R. Costello

An Illustrated Guide to Pruning by E.F. Gilman

Planting Trees and Shrubs for Long-Term Health by R. Hargrave, G.R. 

Johnson, and M.E. Zins

Arboriculture, 4th ed., by R.W. Harris, J.R. Clark, and N.P. Matheny 

Trees and Ice Storms: The Development of Ice Storm-Resistant Urban Tree 

Populations, by R.J. Hauer, M.C. Hruska, and J.O. Dawson 

How to Identify and Manage Dutch Elm Disease by L.M. Haugen

Native Trees, Shrubs, and Vines for Urban and Rural America by G.L. 

Hightshoe

International Society of Arboriculture: http://www.isa-arbor.com, including 

their Tree City USA Bulletin series

National Arbor Day Foundation: http://www.arborday.org

TreeLink: http://www.treelink.org 

Trees for Urban and Suburban Landscapes by E.F. Gilman 1997

Principles and Practice of Planting Trees and Shrubs by G.W. Watson and 

E.B. Himelick

These suggested references are only a starting point. Your local cooperative 

extension agent or state forestry agency can provide you with up-to-date and 

local information.
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Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

81

 Appendix 2: Benefit–Cost Information Tables

Information in this appendix can be used to estimate benefits and costs associated with proposed tree plantings. The tables contain data for representative small 

(goldenrain tree), medium (honeylocust), and large (white ash) deciduous trees and 

a representative conifer (ponderosa pine) (see “Common and Scientific Names” 

section). Data are presented as annual values for each 5-year interval after planting 

(tables 6–17). Annual values incorporate effects of tree loss. Based on the results 

of our survey, we assume that 45 percent of the trees planted die by the end of the 

40-year period.

For the benefits tables (tables 6, 9, 12, 15), there are two columns for each 

5-year interval. In the first column, values describe resource units (RUs): for 

example, the amount of air conditioning energy saved in kWh per year per tree, air 

pollutant uptake in pounds per year per tree, and rainfall intercepted in gallons per 

year per tree. Energy and CO2 benefits for residential yard trees are broken out by 

tree location to show how shading effects differ among trees opposite west-, south-, 

and east-facing building walls. The second column for each 5-year interval contains dollar values obtained by multiplying RUs by local prices (e.g., kWh saved 

[RU] × $/kWh). 

In the costs tables (tables 7, 10, 13, 16), costs are broken down into categories 

for yard and public trees. Costs for yard trees do not differ by planting location 

(i.e., east, west, south walls). Although tree and planting costs occur at year one, 

we divided this value by 5 years to derive an average annual cost for the first 5-year 

period. All other costs are the estimated values for each year and not values averaged over 5 years.

Total net benefits are calculated by subtracting total costs from total benefits 

and are presented in tables 8, 11, 14, and 17. Data are presented for a yard tree 

opposite west-, south-, and east-facing walls, as well as for the public tree.

The last column in each table presents 40-year-average annual values. These 

numbers were calculated by dividing the total costs and benefits by 40 years.
82

GENERAL TECHNICAL REPORT PSW-GTR-205 

Table 6—Annual benefits at 5-year intervals and 40-year average for a representative small tree (goldenrain tree)Benefits/tree

Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40

40-year 

average

 RU Value RU Value RU Value RU Value RU Value RU Value RU Value RU Value RU Value

Dollars Dollars Dollars Dollars Dollars Dollars Dollars Dollars Dollars

Cooling (kWh):

Yard: west 26 2.05 59 4.62 84 6.61 106 8.35 118 9.30 128 10.09 132 10.44 135 10.65 98 7.76

Yard: south 17 1.37 39 3.09 57 4.50 73 5.75 82 6.45 89 7.03 93 7.30 95 7.46 68 5.37Yard: east 24 1.92 56 4.40 81 6.37 103 8.11 115 9.04 124 9.80 129 10.14 131 10.34 95 7.52Public 16 1.30 36 2.85 52 4.10 66 5.19 73 5.78 79 6.26 82 6.47 84 6.60 61 4.82

Heating (kBtu):

Yard: west 31 0.34 66 0.72 96 1.05 122 1.34 134 1.48 144 1.59 148 1.63 151 1.66 111 1.23

Yard: south -11 -0.12 -48 -0.53 -79 -0.87 -107 -1.18 -140 -1.54 -170 -1.87 -188 -2.07 -202 -2.22 -118 -1.30

Yard: east 7 0.08 17 0.19 30 0.33 41 0.45 49 0.54 57 0.63 61 0.67 64 0.71 41 0.45Public 62 0.69 134 1.48 187 2.06 234 2.57 256 2.82 274 3.01 281 3.09 284 3.13 214 2.36

Net energy (kBtu):

Yard: west 290 2.39 652 5.35 933 7.66 1,180 9.68 1,314 10.78 1,424 11.67 1,472 12.07 1,501 12.31 1,096 8.99

Yard: south 163 1.25 344 2.56 492 3.63 622 4.57 679 4.91 721 5.16 737 5.22 744 5.24 563 4.07

Yard: east 251 2.01 575 4.58 838 6.70 1,070 8.56 1,196 9.59 1,300 10.43 1,347 10.81 1,376 11.05 994 7.97Public 227 1.98 496 4.33 707 6.16 892 7.77 989 8.60 1,068 9.27 1,102 9.56 1,121 9.73 825 7.17

Net carbon dioxide (lb):

Yard: west 67 0.23 150 0.50 213 0.71 269 0.90 298 1.00 322 1.08 332 1.11 338 1.13 249 0.83

Yard: south 42 0.14 92 0.31 131 0.44 165 0.55 182 0.61 195 0.65 200 0.67 203 0.68 151 0.50

Yard: east 61 0.20 138 0.46 199 0.66 253 0.84 281 0.94 303 1.01 313 1.05 319 1.07 233 0.78Public 49 0.16 106 0.35 150 0.50 189 0.63 209 0.70 224 0.75 231 0.77 234 0.78 174 0.58

Air pollution (lb)a

:

Ozone uptake 0.0498 0.03 0.1228 0.07 0.1848 0.11 0.2467 0.15 0.2946 0.18 0.3430 0.21 0.3815 0.23 0.4199 0.26 0.2554 0.16Nitrogen dioxide 

uptake+avoided 0.1166 0.07 0.2636 0.16 0.3812 0.23 0.4858 0.30 0.5445 0.33 0.5938 0.36 0.6185 0.38 0.6357 0.39 0.4550 0.28

Sulfur dioxide 

uptake+avoided 0.0970 0.14 0.2187 0.31 0.3155 0.45 0.4006 0.57 0.4471 0.63 0.4852 0.69 0.5024 0.71 0.5129 0.73 0.3724 0.53

Small particulate 

matter uptake + avoided 0.0243 0.03 0.0764 0.09 0.1521 0.17 0.2499 0.29 0.2599 0.30 0.2681 0.31 0.2717 0.31 0.2739 0.31 0.1970 0.23

Volatile organic 

compounds avoided 0.0208 0.00 0.0468 0.01 0.0675 0.01 0.0858 0.02 0.0957 0.02 0.1038 0.02 0.1074 0.02 0.1096 0.02 0.0797 0.02

Biogenic volatile organic 

compounds released -0.013 0.00 -0.040 -0.01 -0.365 -0.07 -1.410 -0.27 -1.410 -0.27 -1.410 -0.27 -1.410 -0.27 -1.410 -0.27 -0.932 -0.18

Avoided + net uptake 0.2954 0.27 0.6885 0.63 0.7359 0.91 0.0620 1.05 0.2349 1.19 0.3871 1.32 0.4746 1.38 0.5453 1.44 0.4280 1.02

Hydrology (gal)

Rainfall interception 48 0.24 122 0.61 191 0.95 259 1.30 321 1.61 385 1.93 436 2.18 487 2.43 281 1.41

Aesthetics and other:

Yard 0 1.58 2.20 2.39 2.39 2.31 2.19 2.04 1.89Public 0 1.82 2.54 2.75 2.76 2.66 2.52 2.35 2.18

Total benefits:

Yard: west 3.12 8.68 12.43 15.31 16.97 18.30 18.93 19.35 14.14Yard: south 1.90 5.69 8.13 9.85 10.71 11.36 11.64 11.82 8.89Yard: east 2.72 7.87 11.43 14.14 15.71 16.99 17.61 18.02 13.06Public 2.66 7.75 11.06 13.49 14.85 15.93 16.42 16.73 12.36

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 percent during the remaining 35 years for a total mortality of 45 percent. RU = resource unit. a Values are the same for yard and public trees.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

83

Table 7—Annual costs (dollars per tree) at 5-year intervals and 40-year average for a representative 

small tree (goldenrain tree)

Costs Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40

40-year 

average

Tree and plantinga:

Yard 30 3.75

Public 30 3.75

Pruning:

Yard 0.10 0.10 0.09 0.09 2.61 2.44 2.28 2.11 1.26

Public 1.96 2.02 1.91 1.80 2.87 2.69 2.50 2.32 2.33

Remove and dispose:

Yard 2.50 1.28 1.72 2.08 2.38 2.65 2.89 3.10 2.02

Public 0.90 1.07 1.44 1.74 1.99 2.22 2.41 2.60 1.70

Infrastructure repair:

Yard 0.05 0.08 0.10 0.12 0.13 0.13 0.14 0.14 0.10

Public 0.39 0.66 0.84 0.95 1.03 1.07 1.09 1.09 0.84

Irrigation:

Yard 0.99 0 0 0 0 0 0 0 0.13

Public 0.87 0 0 0 0 0 0 0 0.12

Cleanup:

Yard 0.01 0.01 0.02 0.02 0.02 0.02 0.02 0.02 0.02

Public 0.07 0.12 0.15 0.17 0.19 0.19 0.20 0.20 0.15

Liability and legal:

Yard 0 0 0 0 0 0 0 0 0

Public 0 0 0 0 0 0 0 0 0

Admin./inspect/other:

Yard 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Public 0.97 1.65 2.09 2.38 2.57 2.68 2.72 2.72 2.10

Total costs:

Yard 33.65 1.48 1.94 2.31 5.14 5.25 5.32 5.38 7.28

Public 35.16 5.52 6.44 7.06 8.65 8.85 8.94 8.92 10.99

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 percent during the remaining 35 years for a total mortality of 45 percent.

a

Although tree and planting costs occur in year 1, this value was divided by 5 years to derive an average annual cost for the first 5-year period.

Table 8—Annual net benefits (dollars per tree) at 5-year intervals and 40-year average for a 

representative small tree (goldenrain tree)

Total net benefits Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40

40-year 

average

Yard: west -31 7 10 13 12 13 14 14 7

Yard: south -32 4 6 8 6 6 6 6 2

Yard: east -31 6 9 12 11 12 12 13 6

Public -33 2 5 6 6 7 7 8 1

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 percent during the remaining 35 years for a total mortality of 45 percent. See tables 6 for annual benefits and table 7 for annual costs.
84

GENERAL TECHNICAL REPORT PSW-GTR-205 

Table 9—Annual benefits (dollars per tree) at 5-year intervals and 40-year average for a representative medium tree (honeylocust) Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40 40-year average Benefits/tree RU Value RU Value RU Value RU Value RU Value RU Value RU Value RU Value RU Value Dollars Dollars Dollars Dollars Dollars Dollars Dollars Dollars Dollars Cooling (kWh): Yard: west 44 3.44 81 6.35 125 9.89 165 13.04 203 16.02 235 18.56 261 20.57 279 21.97 174 13.73 Yard: south 30 2.39 56 4.41 87 6.85 116 9.13 147 11.56 173 13.64 196 15.48 215 16.95 127 10.05 Yard: east 42 3.33 78 6.17 122 9.66 162 12.77 200 15.75 232 18.29 257 20.27 274 21.63 171 13.48 Public 30 2.33 53 4.19 80 6.33 105 8.30 131 10.31 152 12.02 171 13.51 186 14.68 114 8.96 Heating (kBtu): Yard: west 75 0.82 135 1.48 203 2.24 262 2.88 311 3.42 352 3.88 382 4.20 398 4.38 265 2.91 Yard: south 33 0.37 32 0.36 8 0.09 -9 -0.10 -15 -0.16 -19 -0.21 -12 -0.13 3 0.03 3 0.03 Yard: east 43 0.47 85 0.93 135 1.48 181 2.00 230 2.53 271 2.98 304 3.35 327 3.60 197 2.17 Public 109 1.20 191 2.10 284 3.13 362 3.98 424 4.66 475 5.23 511 5.62 530 5.83 361 3.97 Net energy (kBtu): Yard: west 511 4.26 940 7.83 1,458 12.13 1,916 15.92 2,344 19.45 2,706 22.43 2,990 24.76 3,185 26.35 2,006 16.64 Yard: south 336 2.75 591 4.76 876 6.93 1,149 9.03 1,452 11.40 1,710 13.43 1,952 15.35 2,153 16.98 1,277 10.08 Yard: east 465 3.80 868 7.10 1,359 11.14 1,801 14.77 2,228 18.28 2,591 21.27 2,875 23.62 3,071 25.23 1,907 15.65 Public 405 3.53 722 6.29 1,087 9.46 1,415 12.28 1,731 14.97 2,000 17.25 2,224 19.13 2,391 20.51 1,497 12.93 Net carbon dioxide (lb): Yard: west 123 0.41 223 0.74 347 1.16 460 1.54 569 1.90 663 2.22 745 2.49 809 2.70 492 1.64 Yard: south 87 0.29 154 0.51 235 0.78 313 1.04 399 1.33 474 1.58 548 1.83 614 2.05 353 1.18 Yard: east 116 0.39 212 0.71 332 1.11 442 1.48 551 1.84 646 2.16 727 2.43 790 2.64 477 1.59 Public 94 0.32 166 0.55 252 0.84 332 1.11 413 1.38 485 1.62 552 1.84 609 2.03 363 1.21 Air pollution (lb)a

:

Ozone uptake 0.0859 0.05 0.1757 0.11 0.2869 0.18 0.4011 0.24 0.5290 0.32 0.6568 0.40 0.7910 0.48 0.9254 0.56 0.4815 0.29Nitrogen dioxide 

uptake + avoided 0.2039 0.12 0.3766 0.23 0.5843 0.36 0.7746 0.47 0.9647 0.59 1.1291 0.69 1.2695 0.77 1.3782 0.84 0.8351 0.51

Sulfur dioxide 

uptake + avoided 0.1679 0.24 0.3087 0.44 0.4784 0.68 0.6324 0.90 0.7848 1.11 0.9144 1.30 1.0218 1.45 1.1012 1.56 0.6762 0.96

Small particulate matter 

uptake + avoided 0.0410 0.05 0.1070 0.12 0.2200 0.25 0.3647 0.42 0.5093 0.58 0.6465 0.74 0.7756 0.89 0.7926 0.91 0.4321 0.49

Volatile organic 

compounds avoided 0.0361 0.01 0.0664 0.01 0.1028 0.02 0.1358 0.03 0.1684 0.03 0.1962 0.04 0.2192 0.04 0.2361 0.05 0.1451 0.03

Biogenic volatile organic 

compounds released 0 0 -0.003 0 -0.057 -0.01 -0.237 -0.05 -0.532 -0.10 -0.941 -0.18 -1.464 -0.28 -1.464 -0.28 -0.587 -0.11

Avoided + net uptake 0.5346 0.47 1.0318 0.91 1.6159 1.47 2.0717 2.01 2.4245 2.54 2.6023 2.98 2.6131 3.35 2.9695 3.64 1.9829 2.17

Hydrology (gal)

Rainfall interception 75 0.37 166 0.83 291 1.46 430 2.15 609 3.04 788 3.94 998 4.99 1,225 6.13 573 2.86

Aesthetics and other:

Yard 0.85 0.76 6.90 9.65 12.25 14.67 16.87 18.83 10.10Public 0.98 0.88 7.95 11.12 14.12 16.92 19.46 21.71 11.64

Total benefits:

Yard: west 6.37 11.07 23.11 31.27 39.18 46.24 52.47 57.64 33.42

Yard: south 4.73 7.77 17.54 23.88 30.56 36.60 42.40 47.63 26.39Yard: east 5.88 10.31 22.07 30.05 37.95 45.02 51.26 56.47 32.38Public 5.67 9.46 21.18 28.68 36.06 42.70 48.77 54.01 30.82

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 percent during the remaining 35 years for a total mortality of 45 percent. RU = resource unit. a Values are the same for yard and public trees.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

85

Table 10—Annual costs (dollars per tree) at 5-year intervals and 40-year average for a representative 

medium tree (honeylocust)

Costs Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40

40-year 

average

Tree and plantinga:

Yard 30.00 3.75

Public 30.00 3.75

Pruning:

Yard 0.10 0.10 2.93 2.77 2.61 2.44 2.28 4.29 1.93

Public 1.96 2.02 3.23 3.05 2.87 2.69 2.50 11.08 3.03

Remove and dispose:

Yard 2.83 1.28 1.77 2.27 2.78 3.30 3.83 4.38 2.45

Public 2.37 1.07 1.48 1.89 2.32 2.76 3.21 3.67 2.05

Infrastructure repair:

Yard 0.05 0.08 0.11 0.13 0.15 0.17 0.16 0.19 0.13

Public 0.44 0.66 0.86 1.04 1.20 1.33 1.45 1.53 1.00

Irrigation:

Yard 0.99 0 0 0 0 0 0 0 0.13

Public 0.87 0 0 0 0 0 0 0 0.12

Cleanup:

Yard 0.01 0.01 0.02 0.02 0.03 0.03 0.03 0.03 0.02

Public 0.08 0.12 0.15 0.19 0.22 0.24 0.26 0.28 0.18

Liability and legal:

Yard 0 0 0 0 0 0 0 0 0

Public 0 0 0 0 0 0 0 0 0

Admin./inspect/other: Yard 0 0 0 0 0 0 0 0 0

Public 1.09 1.65 2.15 2.60 3.00 3.34 3.62 3.83 2.50

Total costs:

Yard 33.99 1.48 4.83 5.19 5.56 5.94 6.30 8.90 8.41

Public 36.81 5.52 7.88 8.78 9.61 10.37 11.05 20.41 12.64

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 percent 

during the remaining 35 years for a total mortality of 45 percent.

a

Although tree and planting costs occur in year 1, this value was divided by 5 years to derive an average annual cost for the first 5-year 

period.

Table 11—Annual net benefits (dollars per tree) at 5-year intervals and 40-year average for a 

representative medium tree (honeylocust)

Total net benefits Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40

40-year 

average

 Yard: west -28 10 18 26 34 40 46 49 25

 Yard: south -29 6 13 19 25 31 36 39 18

 Yard: east -28 9 17 25 32 39 45 48 24

 Public -31 4 13 20 26 32 38 34 18

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 percent during the remaining 35 years for a total mortality of 45 percent. See tables 9 for annual benefits and table 10 for annual costs.
86

GENERAL TECHNICAL REPORT PSW-GTR-205 

Table 12—Annual benefits (dollars per tree) at 5-year intervals and 40-year average for a representative large tree (white ash) Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40 40-year average Benefits/tree RU Value RU Value RU Value RU Value RU Value RU Value RU Value RU Value RU Value Dollars Dollars Dollars Dollars Dollars Dollars Dollars Dollars Dollars Cooling (kWh): Yard: west 29 2.28 74 5.81 143 11.27 232 18.27 335 26.40 446 35.16 571 45.00 649 51.19 310 24.42 Yard: south 16 1.27 44 3.47 90 7.11 159 12.57 243 19.14 344 27.15 472 37.23 561 44.25 241 19.02 Yard: east 27 2.13 71 5.60 141 11.08 228 18.00 329 25.95 431 34.02 551 43.48 629 49.59 301 23.73 Public 15 1.18 39 3.09 79 6.19 134 10.58 201 15.87 285 22.47 397 31.34 479 37.77 204 16.06 Heating (kBtu): Yard: west 34 0.37 93 1.02 188 2.07 302 3.32 423 4.65 499 5.49 530 5.83 514 5.65 323 3.55 Yard: south 11 0.12 5 0.06 -17 -0.19 -5 -0.06 10 0.11 18 0.20 -6 -0.07 -40 -0.44 -3 -0.03 Yard: east 8 0.09 39 0.43 102 1.12 197 2.16 300 3.30 370 4.07 400 4.40 391 4.30 226 2.48 Public 59 0.65 146 1.60 278 3.05 428 4.71 594 6.53 726 7.99 830 9.13 866 9.53 491 5.40 Net energy (kBtu): Yard: west 324 2.66 830 6.83 1,618 13.34 2,618 21.59 3,771 31.05 4,958 40.65 6,237 50.83 7,007 56.84 3,420 27.97 Yard: south 172 1.39 445 3.52 885 6.93 1,590 12.52 2,437 19.24 3,462 27.35 4,715 37.16 5,573 43.81 2,410 18.99 Yard: east 278 2.22 749 6.03 1,507 12.20 2,480 20.16 3,590 29.24 4,684 38.08 5,914 47.88 6,680 53.89 3,235 26.21 Public 209 1.83 538 4.69 1,063 9.24 1,770 15.29 2,606 22.40 3,576 30.46 4,804 40.46 5,657 47.30 2,528 21.46 Net carbon dioxide (lb): Yard: west 76 0.25 197 0.66 386 1.29 634 2.12 926 3.09 1243 4.15 1,597 5.33 1,783 5.95 855 2.86 Yard: south 43 0.14 117 0.39 239 0.80 430 1.44 663 2.21 950 3.17 1,304 4.36 1,513 5.05 657 2.20 Yard: east 68 0.23 184 0.62 370 1.24 614 2.05 898 3.00 1,194 3.99 1,536 5.13 1,721 5.75 823 2.75 Public 46 0.16 123 0.41 246 0.82 422 1.41 635 2.12 895 2.99 1,228 4.10 1,428 4.77 628 2.10 Air pollution (lb)a

:

Ozone uptake 0.0466 0.03 0.1349 0.08 0.2812 0.17 0.5225 0.32 0.8427 0.51 1.2776 0.78 1.8739 1.14 2.3918 1.46 0.9214 0.56Nitrogen dioxide 

uptake + avoided 0.1203 0.07 0.3168 0.19 0.6303 0.38 1.0589 0.65 1.5675 0.96 2.1475 1.31 2.8580 1.74 3.3517 2.05 1.5064 0.92

Sulfur dioxide 

uptake + avoided 0.1003 0.14 0.2626 0.37 0.5211 0.74 0.8687 1.23 1.2773 1.81 1.7378 2.46 2.2980 3.26 2.6758 3.79 1.2177 1.73

Small particulate matter 

uptake + avoided 0.0252 0.03 0.0828 0.09 0.2098 0.24 0.4465 0.51 0.7683 0.88 1.1683 1.34 1.2883 1.47 1.3690 1.57 0.6698 0.77

Volatile organic 

compounds avoided 0.0215 0.00 0.0564 0.01 0.1118 0.02 0.1864 0.04 0.2739 0.05 0.3723 0.07 0.4916 0.09 0.5718 0.11 0.2607 0.05

Biogenic volatile organic 

compounds released 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Avoided + net uptake 0.3139 0.28 0.8534 0.75 1.7542 1.56 3.0830 2.74 4.7297 4.21 6.7034 5.96 8.8100 7.71 10.3602 8.97 4.5760 4.02

Hydrology (gal)

Rainfall interception 42 0.21 139 0.70 317 1.59 638 3.19 1,073 5.37 1,705 8.52 2,617 13.09 3,432 17.16 1,245 6.23

Aesthetics and other:

Yard 0.38 6.26 13.26 22.93 35.70 51.94 71.93 95.79 37.27

Public 0.44 7.22 15.29 26.44 41.17 59.91 82.97 110.48 42.99

Total benefits:

Yard: west 3.78 15.20 31.03 52.57 79.42 111.23 148.90 184.72 78.35

Yard: south 2.40 11.62 24.13 42.82 66.74 96.95 134.25 170.78 68.71

Yard: east 3.31 14.35 29.84 51.08 77.52 108.50 145.74 181.56 76.49Public 2.91 13.77 28.50 49.08 75.27 107.85 148.33 188.68 76.80

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 percent during the remaining 35 years for a total mortality of 45 percent. RU = resource unit. a Values are the same for yard and public trees.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

87

Table 13—Annual costs (dollars per tree) at 5-year intervals and 40-year average for a representative 

large tree (white ash)

Costs Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40

40-year 

average

Tree and plantinga:

Yard 30.00 3.75

Public 30.00 3.75

Pruning:

Yard 0.10 3.10 2.93 2.77 2.61 4.96 4.62 4.29 2.82

Public 1.96 3.41 3.23 3.05 2.87 12.81 11.95 11.08 5.80

Remove and dispose:

Yard 2.55 1.34 2.03 2.79 3.62 4.53 5.52 6.58 3.11

Public 2.13 1.12 1.70 2.33 3.03 3.79 4.62 5.50 2.66

Infrastructure repair:

Yard 0.05 0.09 0.12 0.16 0.20 0.23 0.26 0.29 0.16

Public 0.39 0.69 0.99 1.28 1.56 1.83 2.08 2.30 1.28

Irrigation:

Yard 0.99 0 0 0 0 0 0 0 0.13

Public 0.87 0 0 0 0 0 0 0 0.12

Cleanup:

Yard 0.01 0.02 0.02 0.03 0.04 0.04 0.05 0.05 0.03

Public 0.07 0.12 0.18 0.23 0.28 0.33 0.37 0.41 0.23

Liability and legal:

Yard 0 0 0 0 0 0 0 0 0

Public 0 0 0 0 0 0 0 0 0

Admin./inspect/other:

Yard 0 0 0 0 0 0 0 0 0

Public 0.99 1.72 2.46 3.20 3.91 4.59 5.21 5.76 3.21

Total costs:

Yard 33.70 4.54 5.11 5.75 6.46 9.76 10.45 11.21 9.99

Public 36.42 7.07 8.56 10.10 11.67 23.37 24.24 25.08 17.06

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 percent 

during the remaining 35 years for a total mortality of 45 percent.

a

Although tree and planting costs occur in year 1, this value was divided by 5 years to derive an average annual cost for the first 5-year period.

Table 14—Annual net benefits (dollars per tree) at 5-year intervals and 40-year average for a 

representative large tree (white ash)

Total net benefits Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40

40-year 

average

Yard: west -30 11 26 47 73 101 118 138 61

Yard: south -31 7 19 37 60 87 104 125 52

Yard: east -30 10 25 45 71 99 115 135 60

Public -34 7 20 39 64 84 104 129 53

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 percent 

during the remaining 35 years for a total mortality of 45 percent.

See tables 12 for annual benefits and table 13 for annual costs.
88

GENERAL TECHNICAL REPORT PSW-GTR-205 

Table 15—Annual benefits (dollars per tree) at 5-year intervals and 40-year average for a representative conifer tree (ponderosa pine) Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40 40-year average Benefits/tree RU Value RU Value RU Value RU Value RU Value RU Value RU Value RU Value RU Value Dollars Dollars Dollars Dollars Dollars Dollars Dollars Dollars Dollars Cooling (kWh): Yard: west 10 0.82 36 2.87 74 5.82 115 9.09 153 12.05 186 14.66 214 16.87 235 18.49 128 10.08 Yard: south 7 0.59 25 1.94 48 3.75 75 5.95 101 7.95 127 9.98 149 11.76 168 13.27 88 6.90 Yard: east 10 0.78 34 2.66 68 5.36 109 8.59 146 11.53 179 14.15 208 16.37 228 18.00 123 9.68 Public 7 0.59 24 1.86 44 3.50 67 5.25 87 6.82 106 8.34 122 9.66 137 10.77 74 5.85 Heating (kBtu): Yard: west 17 0.19 39 0.43 57 0.63 82 0.90 105 1.16 129 1.42 151 1.66 165 1.82 93 1.03 Yard: south 12 0.13 -20 -0.22 -102 -1.12 -303 -3.33 -498 -5.48 -609 -6.70 -686 -7.54 -716 -7.88 -365 -4.02 Yard: east 6 0.07 2 0.02 -15 -0.16 -12 -0.13 -6 -0.07 13 0.15 34 0.38 51 0.56 9 0.10 Public 30 0.33 90 0.99 164 1.80 238 2.62 304 3.34 356 3.91 397 4.37 424 4.67 250 2.75 Net energy (kBtu): Yard: west 122 1.02 403 3.30 795 6.44 1,235 9.99 1,633 13.20 1,989 16.09 2,290 18.53 2,511 20.31 1,372 11.11 Yard: south 87 0.72 226 1.72 374 2.63 451 2.62 510 2.47 657 3.28 807 4.22 966 5.39 510 2.88 Yard: east 105 0.85 340 2.68 664 5.19 1,077 8.46 1,456 11.46 1,808 14.30 2,111 16.75 2,334 18.56 1,237 9.78 Public 105 0.92 326 2.85 607 5.30 904 7.87 1,169 10.17 1,414 12.25 1,622 14.02 1,791 15.44 992 8.60 Net carbon dioxide (lb): Yard: west 28 0.09 95 0.32 190 0.63 300 1.00 401 1.34 494 1.65 576 1.92 644 2.15 341 1.14 Yard: south 20 0.07 60 0.20 110 0.37 162 0.54 209 0.70 269 0.90 327 1.09 386 1.29 193 0.64 Yard: east 25 0.08 84 0.28 168 0.56 274 0.91 372 1.24 466 1.55 548 1.83 616 2.06 319 1.07 Public 22 0.07 71 0.24 134 0.45 205 0.68 270 0.90 334 1.12 392 1.31 447 1.49 234 0.78 Air pollution (lb)a

:

Ozone uptake 0.0327 0.02 0.1122 0.07 0.2197 0.13 0.3548 0.22 0.4939 0.30 0.6454 0.39 0.8004 0.49 0.9604 0.59 0.4524 0.28Nitrogen dioxide 

uptake + avoided 0.0528 0.03 0.1748 0.11 0.3416 0.21 0.5335 0.33 0.7104 0.43 0.8808 0.54 1.0323 0.63 1.1587 0.71 0.6106 0.37

Sulfur dioxide 

uptake + avoided 0.0408 0.06 0.1370 0.19 0.2702 0.38 0.4236 0.60 0.5627 0.80 0.6918 0.98 0.8026 1.14 0.8894 1.26 0.4773 0.68

Small particulate matter 

uptake + avoided 0.0107 0.01 0.0550 0.06 0.1505 0.17 0.2989 0.34 0.4575 0.52 0.6200 0.71 0.7814 0.89 0.7999 0.92 0.3967 0.45

Volatile organic 

compounds avoided 0.0088 0 0.0292 0.01 0.0575 0.01 0.0900 0.02 0.1194 0.02 0.1467 0.03 0.1702 0.03 0.1885 0.04 0.1013 0.02

Biogenic volatile organic 

compounds released -0.002 0.00 -0.005 0.00 -0.031 -0.01 -0.243 -0.05 -0.805 -0.15 -1.885 -0.36 -3.651 -0.70 -3.651 -0.70 -1.284 -0.25

Avoided + net uptake 0.1439 0.12 0.5029 0.44 1.0087 0.90 1.4576 1.46 1.5387 1.92 1.0998 2.29 -0.0640 2.48 0.3459 2.81 0.7542 1.55

Hydrology (gal)

Rainfall interception 26 0.13 92 0.46 187 0.94 393 1.97 616 3.08 950 4.75 1316 6.58 1775 8.88 669 3.35

Aesthetics and other:

Yard 0.36 0.32 3.21 6.96 11.73 17.24 23.23 29.44 11.56Public 0.41 0.37 3.70 8.03 13.52 19.88 26.79 33.95 13.33

Total benefits:

Yard: west 1.72 4.84 12.12 21.38 31.27 42.01 52.75 63.59 28.71Yard: south 1.40 3.14 8.05 13.54 19.90 28.45 37.61 47.80 19.99Yard: east 1.55 4.18 10.80 19.75 29.44 40.13 50.87 61.74 27.31Public 1.66 4.35 11.28 20.00 29.60 40.29 51.19 62.57 27.62

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 percent during the remaining 35 years for a total mortality of 45 percent. RU = resource unit. a Values are the same for yard and public trees.
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

89

Table 16—Annual costs (dollars per tree) at 5-year intervals and 40-year average for a representative 

conifer tree (ponderosa pine)

Costs Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40

40-year 

average

Tree and planting a:

Yard 30.00 3.75 

Public 30.00 3.75 

Pruning:

Yard 0.10 0.10 0.09 2.77 2.61 2.44 2.28 4.29 1.69

Public 1.96 2.02 1.91 3.05 2.87 2.69 2.50 11.08 3.32

Remove and dispose:

Yard 2.55 1.36 2.04 2.71 3.38 4.06 4.73 5.41 2.79

Public 2.13 1.14 1.70 2.27 2.83 3.39 3.96 4.52 2.39

Infrastructure repair:

Yard 0.05 0.09 0.12 0.16 0.18 0.21 0.22 0.24 0.15

Public 0.39 0.70 0.99 1.24 1.46 1.64 1.79 1.89 1.17

Irrigation:

Yard 0.99 0 0 0 0 0 0 0 0.13

Public 0.87 0 0 0 0 0 0 0 0.12

Cleanup:

Yard 0.01 0.02 0.02 0.03 0.03 0.04 0.04 0.04 0.03

Public 0.07 0.13 0.18 0.22 0.26 0.30 0.32 0.34 0.21

Liability and legal:

Yard 0 0 0 0 0 0 0 0 0

Public 0 0 0 0 0 0 0 0 0

Admin./inspect/other:

Yard 0 0 0 0 0 0 0 0 0

Public 0.99 0.93 2.47 3.11 3.65 4.10 4.46 4.73 2.93

Total costs:

Yard 33.70 1.56 2.27 5.66 6.21 6.74 7.27 9.98 8.54

Public 36.42 4.92 7.26 9.90 11.09 12.14 13.05 22.59 13.90

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 percent 

during the remaining 35 years for a total mortality of 45 percent. RU = resource unit. 

a

Although tree and planting costs occur in year 1, this value was divided by 5 years to derive an average annual cost for the first 5-year 

period.

Table 17—Annual net benefits (dollars per tree) at 5-year intervals and 40-year average for a 

representative conifer tree (ponderosa pine)

Total net benefits Year 5 Year 10 Year 15 Year 20 Year 25 Year 30 Year 35 Year 40

40-year 

average

Yard: west -32 3 10 16 25 35 45 54 20

Yard: south -32 2 6 8 14 22 30 38 11

Yard: east -32 3 9 14 23 33 44 52 19

Public -35 -1 4 10 19 28 38 40 14

Note: Annual values incorporate effects of tree loss. We assume that 15 percent of trees planted die during the first 5 years and 30 

percent during the remaining 35 years for a total mortality of 45 percent. See tables 15 for annual benefits and table 16 for annual 

costs.
90

GENERAL TECHNICAL REPORT PSW-GTR-205 
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

91

Appendix 3: Procedures for Estimating Benefits and 

Costs

Approach

Pricing Benefits and Costs

In this study, annual benefits and costs over a 40-year planning horizon were 

estimated for newly planted trees in three residential yard locations (east, south, 

and west of the dwelling unit) and a public streetside or park location. Trees in 

these hypothetical locations are called “yard” and “public” trees, respectively. 

Prices were assigned to each cost (e.g., planting, pruning, removal, irrigation, 

infrastructure repair, liability) and benefit (e.g., heating/cooling, energy savings, 

air-pollution reduction, stormwater-runoff reduction) through direct estimation 

and implied valuation of benefits as environmental externalities. This approach 

made it possible to estimate the net benefits of plantings in “typical” locations 

with “typical” tree species.

To account for differences in the mature size and growth rates of different 

tree species, we report results for a small (goldenrain tree), medium (honeylocust), and large (white ash) deciduous tree and for a conifer (ponderosa pine) (see 

“Common and Scientific Names” section). Results are reported for 5-year intervals for 40 years.

Mature tree height is frequently used to characterize small, medium, and large 

species because matching tree height to available overhead space is an important 

design consideration. However, in this analysis, leaf surface area (LSA) and 

crown diameter were also used to characterize mature tree size. These additional 

measurements are useful indicators for many functional benefits of trees that relate 

to leaf-atmosphere processes (e.g., interception, transpiration, photosynthesis). Tree 

growth rates, dimensions, and LSA estimates are based on tree growth modeling.

Growth Modeling 

Growth models are based on data collected in Albuquerque, New Mexico. An 

inventory of Albuquerque’s municipal trees was provided by the city’s Parks and 

Recreation Department. Completed in 2005, the inventory included 21,519 trees, 

mainly in parks. 

Tree-growth models developed from Albuquerque data were used as the basis 

for modeling tree growth for this report. Using Albuquerque’s tree inventory, we 

measured a stratified random sample of 20 of the most common tree species to 

establish relations between tree age, size, leaf area, and biomass. 
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For the growth models, information spanning the life cycle of predominant 

tree species was collected. The inventory was stratified into the following nine 

diameter-at-breast-height (d.b.h.) classes:

• 0 to 2.9 in

• 3 to 5.9 in

• 6 to 11.9 in

• 12 to 17.9 in

• 18 to 23.9 in

• 24 to 29.9 in

• 30 to 35.9 in

• 36 to 41.9 in

• ≥ 42 in

Thirty to seventy trees of each species were randomly selected for surveying, 

along with an equal number of alternative trees. Tree measurements included d.b.h. 

(to nearest 0.1 cm [0.04 in] by sonar measuring device), tree crown and bole height 

(to nearest 0.5 m [1.6 ft] by clinometer), crown diameter in two directions (parallel 

and perpendicular to nearest street to nearest 0.5 m [1.6 ft] by sonar measuring 

device), tree condition and location. Replacement trees were sampled when trees 

from the original sample population could not be located. Tree age was determined 

by street-tree managers. Field work was conducted in June 2005.

Crown volume and leaf area were estimated from computer processing of 

tree-crown images obtained with a digital camera. The method has shown greater 

accuracy than other techniques (±20 percent of actual leaf area) in estimating 

crown volume and leaf area of open-grown trees (Peper and McPherson 2003).

Linear regression was used to fit predictive models with d.b.h. as a function 

of age for each of the 20 sampled species. Predictions of LSA, crown diameter, 

and height metrics were modeled as a function of d.b.h. by using best-fit models. 

After inspecting the growth curves for each species, we selected the typical small, 

medium, and large tree species for this report.

Reporting Results

Results are reported in terms of annual values per tree planted. However, to make 

these calculations realistic, mortality rates are included. Based on our survey of 

regional municipal foresters and commercial arborists, this analysis assumed that 

45 percent of the hypothetical planted trees died over the 40-year period. Annual 

mortality rates were 3 percent for the first 5 years, and 0.85 percent per year after 
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

93

that, or 45 percent total. This accounting approach “grows” trees in different locations and uses computer simulation to directly calculate the annual flow of benefits 

and costs as trees mature and die (McPherson 1992).

Benefits and costs are directly connected with tree-size variables such as trunk 

d.b.h., tree canopy cover, and LSA. For instance, pruning and removal costs usually 

increase with tree size, expressed as d.b.h. For some parameters, such as sidewalk 

repair, costs are negligible for young trees but increase relatively rapidly as tree 

roots grow large enough to heave pavement. For other parameters, such as air-pollutant uptake and rainfall interception, benefits are related to tree canopy cover and 

leaf area.

Most benefits occur on an annual basis, but some costs are periodic. For 

instance, street trees may be pruned on regular cycles but are removed in a less 

regular fashion (e.g., when they pose a hazard or soon after they die). In this analysis, most costs and benefits are reported for the year in which they occur. However, 

periodic costs such as pruning, pest and disease control, and infrastructure repair 

are presented on an average annual basis. Although spreading one-time costs over 

each year of a maintenance cycle does not alter the 40-year nominal expenditure, it 

can lead to inaccuracies if future costs are discounted to the present.

Benefit and Cost Valuation

Source of cost estimates—

Frequency and costs of tree management were estimated based on surveys with 

municipal foresters from Albuquerque, New Mexico; Sandy City, Utah; and Logan, 

Utah, provided information on tree management costs on residential properties.

Pricing benefits—

To monetize effects of trees on energy use, we take the perspective of a residential 

customer by using retail electricity and natural-gas prices for utilities serving 

Albuquerque. The retail price of energy reflects a full accounting of costs as paid 

by the end user, such as the utility costs of power generation, transmission, distribution, administration, marketing, and profit. This perspective aligns with our modeling method, which calculates energy effects of trees based on differences among 

consumers in heating and air conditioning equipment types, saturations, building 

construction types, and base loads. 

The preferred way to value air quality benefits from trees is to first determine 

the costs of damages to human health from polluted air, then calculate the value of 

reduced costs because trees are cleaning the air. Economic valuation of damages 

to human health usually uses information on willingness to pay to avoid damages 
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GENERAL TECHNICAL REPORT PSW-GTR-205 

obtained via interviews or direct estimates of the monetary costs of damages (e.g., 

alleviating headaches, extending life). Empirical correlations developed by Wang 

and Santini (1995) reviewed 5 studies and 15 sets of regional cost data to relate perton costs of various pollutant emissions to regional ambient air quality measurements and population size. We use their damage-based estimates unless the values 

are negative, in which case we use their control cost-based estimates. 

Calculating Benefits

Calculating Energy Benefits—

The prototypical building used as a basis for the simulations was typical of post1980 construction practices and represents approximately one-third of the total 

single-family residential housing stock in the Interior West region. The house was 

a one-story, wood-frame, slab-on-grade building with a conditioned floor area of 

1,660 ft2, window area (double-glazed) of 197 ft2, and wall and ceiling insulation 

of R13 and R29, respectively. The central cooling system had a seasonal energy

efficiency ratio (SEER) of 10, and the natural-gas furnace had an annual fuel utilization efficiency (AFUE) of 78 percent. Building footprints were square, reflecting 

average impacts for a large number of buildings (McPherson and Simpson 1999). 

Buildings were simulated with 1.5-ft overhangs. Blinds had a visual density of 37 

percent and were assumed to be closed when the air conditioner was operating. 

Summer thermostat settings were 78 °F; winter settings were 68 °F during the day 

and 60 °F at night. Because the prototype building was larger, but more energy 

efficient, than most other construction types, our projected energy savings can be 

considered similar to those for older, less thermally efficient, but smaller buildings. 

The energy simulations relied on typical meteorological data from Albuquerque 

(Marion and Urban 1995).

Calculating energy savings—

The dollar value of energy savings was based on regional average residential 

electricity and natural-gas prices of $0.078844/kWh and $1.10/therm, respectively. 

Electricity and natural-gas prices were for 2005 for Albuquerque (PNM 2005, Public Service Company of New Mexico 2006). Homes were assumed to have central 

air conditioning and natural-gas heating.

Calculating shade effects—

Residential yard trees were within 60 ft of homes so as to directly shade walls and 

windows. Shade effects of these trees on building energy use were simulated for 

small, medium, and large trees at three tree-to-building distances, following methods outlined by McPherson and Simpson (1999). The small tree (goldenrain tree) 
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

95

had visual densities of 42 percent during summer and 25 percent during winter, the 

medium tree (honeylocust) 67 percent during summer and 33 percent during winter, 

and the large tree (white ash) 78 percent during summer and 17 percent during 

winter. The conifer (ponderosa pine) had a visual density of 28 percent.

Leaf-off values for use in calculating winter shade were based on published values where available (Hammond et al. 1980, McPherson 1984). Foliation periods for 

deciduous trees were obtained from the literature (Hammond et al.1980, McPherson 

1984) and adjusted for Albuquerque’s climate based on consultation with forestry 

supervisors and a representative of the Osuna Nursery (Angstrom 2006, Russell 

and Hart 2006). The foliation periods of the trees were as follows: small tree: 20 

April–10 November, medium tree: 20 April–30 October, large tree: 20 April–10 

November. 

Results of shade effects for each tree were averaged over distance and weighted 

by occurrence within each of three distance classes: 28 percent at 10 to 20 ft, 68 

percent at 20 to 40 ft, and 4 percent at 40 to 60 ft (McPherson and Simpson 1999). 

Results are reported for trees shading east-, south-, and west-facing surfaces. Our 

results for public trees are conservative in that we assumed that they do not provide 

shading benefits. For example, in Modesto, California, 15 percent of total annual 

dollar energy savings from street trees was due to shade and 85 percent due to 

climate effects (McPherson et al. 1999a).

Calculating climate effects—

In addition to localized shade effects, which were assumed to accrue only to 

residential yard trees, lowered air temperatures and windspeeds from increased 

neighborhood tree cover (referred to as climate effects) produced a net decrease 

in demand for winter heating and summer cooling (reduced windspeeds by themselves may increase or decrease cooling demand, depending on the circumstances). 

Climate effects on energy use, air temperature and windspeed, as a function of 

neighborhood canopy cover, were estimated from published values (McPherson and 

Simpson 1999). Existing tree canopy plus building cover was 50 percent based on 

estimates for Miami and Dallas (McPherson and Simpson 1999). Canopy cover was 

calculated to increase by 3.2 percent, 5.3 percent, 6.8 percent, and 3.3 percent for 

20-year-old small, medium, and large deciduous and coniferous trees, respectively, 

based on an effective lot size (actual lot size plus a portion of adjacent street and 

other rights-of-way) of 10,000 ft2, and one tree on average was assumed per lot. 

Climate effects were estimated by simulating effects of wind reductions and airtemperature reductions on energy use. Climate effects accrued for both public and 

yard trees.
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GENERAL TECHNICAL REPORT PSW-GTR-205 

Atmospheric Carbon Dioxide Reduction

Calculating reduction in CO2 emissions from power plants—

Conserving energy in buildings can reduce carbon dioxide (CO2) emissions from 

power plants. These reduced emissions were calculated as the product of energy 

savings for heating and cooling by using CO2 emission factors (table 18) based 

on data for PNM Resources, the local utility company in Albuquerque, where the 

average fuel mix consists almost entirely of coal (98 percent), and natural gas (1.8 

percent) (U.S. EPA 2003). The value of $6.68 per ton CO2 reduction (table 18) was 

based on the average value in Pearce (2003).

Calculating carbon storage—

Sequestration, the net rate of CO2 storage in above- and belowground biomass over 

the course of one growing season, was calculated by using tree height and d.b.h. 

data with biomass equations (Pillsbury et al. 1998). Volume estimates were converted to green and dry-weight estimates (Markwardt 1930) and divided by 78 percent to incorporate root biomass. Dry-weight biomass was converted to carbon (50 

percent) and these values were converted to CO2. The amount of CO2 sequestered 

each year is the annual increment of CO2 stored as trees increase their biomass.

Calculating CO2 released by power equipment—

Tree-related CO2 emissions, based on gasoline and diesel fuel consumption during tree care in our survey cities, were calculated by using the value 1.36 lb of CO2

per in d.b.h. (Russell and Hart 2006). This amount may overestimate CO2 release 

associated with less intensively maintained residential yard trees.

Calculating CO2 released during decomposition—

To calculate CO2 released through decomposition of dead woody biomass, we 

conservatively estimated that dead trees were removed and mulched in the year 

Table 18­—­Emissions factors and implied values for carbon dioxide and criteria air pollutants

Emission factor Electricitya Natural gasb Implied valuec

Pounds per megawatt hour Pounds per million British thermal units (Dollars per pound

Carbon dioxide 2,328 118 0.0034

Nitrogen dioxide 5.064 0.1020 0.61

Sulfur dioxide 4.598 0.0006 1.42

Small particulate matter 0.988 0.0075 1.14

Volatile organic compounds 0.983 0.0054 0.19

a Source: U.S. EPA 2003, except Ottinger et al. 1990 for volatile organic compounds.

b Source: U.S. EPA 1998.

c Carbon dioxide from Pearce 2003. Value for others based on methods of Wang and Santini (1995) using emissions concentrations 

from U.S. EPA (2003) and population estimates from the U.S. Census Bureau (2006).
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

97

that death occurred, and that 80 percent of their stored carbon was released to the 

atmosphere as CO2 in the same year (McPherson and Simpson 1999).

Calculating reduction in air pollutant emissions—

Reductions in building energy use also result in reduced emission of air pollutants 

from power plants and space-heating equipment. Volatile organic hydrocarbons 

(VOCs) and nitrogen dioxide (NO2)—both precursors of ozone formation—as well 

as sulfur dioxide (SO2) and particulate matter of <10 micron diameter (PM10) were 

considered. Changes in average annual emissions and their monetary values were 

calculated in the same way as for CO2, by using utility-specific emissions factors 

for electricity and heating fuels (Ottinger et al. 1990, U.S. EPA 1998). The price 

of emissions savings was derived from models that calculate the marginal cost of 

controlling different pollutants to meet air quality standards (Wang and Santini 

1995). Emissions concentrations were obtained from U.S. EPA (2003; table 18), and 

population estimates from the U.S. Census Bureau (2006).

Calculating pollutant uptake by trees—

Trees also remove pollutants from the atmosphere. The modeling method we 

applied was developed by Scott et al. (1998). It calculates hourly pollutant dry 

deposition per tree expressed as the product of deposition velocity (Vd =1/[Ra + Rb

+ Rc]), pollutant concentration (C), canopy-projection area (CP), and a time step, 

where Ra, Rb, and Rc are aerodynamic, boundary layer, and stomatal resistances. 

Hourly deposition velocities for each pollutant were calculated during the growing 

season by using estimates for the resistances (Ra + Rb + Rc ) for each hour throughout the year. Hourly concentrations for NO2, SO2, O3, and PM10 and hourly meteorological data (i.e., air temperature, windspeed, solar radiation) from Albuquerque 

and the surrounding area for 2001 were obtained from the U.S. EPA. The year 2001 

was chosen because it closely approximated long-term, regional climate records. To 

set a value for pollutant uptake by trees we used the procedure described above for 

emissions reductions (table 18). The monetary value for NO2 was used for ozone.

Estimating BVOC emissions from trees—

Annual emissions for biogenic volatile organic compounds (BVOCs) were estimated for the three tree species by using the algorithms of Guenther et al. (1991, 

1993). Annual emissions were simulated during the growing season over 40 years. 

The emission of carbon as isoprene was expressed as a product of the base emission 

rate (μg C per g dry foliar biomass per hr), adjusted for sunlight and temperature 

and the amount of dry, foliar biomass present in the tree. Monoterpene emissions 

were estimated by using a base emission rate adjusted for temperature. The base 

emission rates for the three species were based on values reported in the literature 
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(Benjamin and Winer 1998). Hourly emissions were summed to get monthly and 

annual emissions.

Annual dry foliar biomass was derived from field data collected in Albuquerque, New Mexico, during the summer of 2005. The amount of foliar biomass 

present for each year of the simulated tree’s life was unique for each species. Hourly 

air temperature and solar radiation data for 2001 described in the pollutant uptake 

section were used as model inputs.

Calculating net air quality benefits—

Net air quality benefits were calculated by subtracting the costs associated with 

BVOC emissions from benefits associated with pollutant uptake and reduced 

power plant emissions. The ozone-reduction benefit from lowering summertime air 

temperatures, thereby reducing hydro-carbon emissions from anthropogenic and 

biogenic sources, was estimated as a function of canopy cover following McPherson and Simpson (1999). They used peak summer air temperature reductions of 

0.4 °F for each percentage increase in canopy cover. Hourly changes in air temperature were calculated by reducing this peak air temperature at every hour based on 

hourly maximum and minimum temperature for that day, scaled by magnitude of 

maximum total global solar radiation for each day relative to the maximum value 

for the year. Simulation results from Los Angeles indicate that ozone reduction 

benefits of tree planting with “low-emitting” species exceeded costs associated with 

their BVOC emissions (Taha 1996).

Stormwater Benefits

Estimating rainfall interception by tree canopies—

A numerical simulation model was used to estimate annual rainfall interception 

(Xiao et al. 2000). The interception model accounted for water intercepted by the 

tree, as well as throughfall and stem flow. Intercepted water is stored temporarily 

on canopy leaf and bark surfaces. Rainwater evaporates or drips from leaf surfaces 

and flows down the stem surface to the ground. Tree-canopy parameters that affect 

interception include species, leaf and stem surface areas, shade coefficients (visual 

density of the crown), foliation periods, and tree dimensions (e.g., tree height, 

crown height, crown diameter, and d.b.h.). Tree-height data were used to estimate 

windspeed at different heights above the ground and resulting rates of evaporation.

The volume of water stored in the tree crown was calculated from crownprojection area (area under tree dripline), leaf area indices (LAI, the ratio of LSA 

to crown projection area), and the depth of water captured by the canopy surface. 

Gap fractions, foliation periods, and tree surface saturation storage capacity 
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

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influence the amount of projected throughfall. Tree surface saturation was 0.04 in 

for all trees. 

Hourly meteorological and rainfall data for 1998 at the Albuquerque International Airport climate monitoring station (National Oceanic and Atmospheric 

Administration/National Weather Service, site number 0234, latitude 35° 02’ N, 

longitude 106° 37’ W, elevation 5,310 ft) in Bernalillo County, New Mexico, were 

used in this simulation. The year 1998 was chosen because it most closely approximated the 30-year average rainfall of 9.47 in. Annual precipitation at Albuquerque 

during 1998 was 9.83 in. Storm events less than 0.1 in were assumed not to produce 

runoff and were dropped from the analysis. More complete descriptions of the 

interception model can be found in Xiao et al. (1998, 2000).

Calculating water quality protection and flood control benefit—

The benefits that result from reduced peak runoff include reduced property damage 

from flooding and reduced loss of soil and habitat from erosion and sediment flow. 

Reduced runoff also results in improved water quality in streams, lakes, and rivers. 

This can translate into improved aquatic habitats, less human illness from contact 

with contaminated water, and reduced stormwater treatment costs. 

Albuquerque, New Mexico, spends approximately $11.5 million annually on 

operations, maintenance, and improvements to its stormwater management system 

(Hogan 2006). To calculate annual runoff we assigned curve numbers for each 

land use (USDA SCS 1986). Land use percentages were obtained from the city 

geographic information system database. We calculated runoff depth for each land 

use and found the citywide total to be 0.99 in. Given Albuquerque’s area of 132.2 

mi2, the total annual runoff was 2.3 billion gal. The annual stormwater control cost 

($11.5 million per 2.3 billion gal) was estimated to be $0.005 per gal of runoff. 

Aesthetic and Other Benefits

Many benefits attributed to urban trees are difficult to translate into economic 

terms. Beautification, privacy, wildlife habitat, shade that increases human comfort, 

sense of place and wellbeing are services that are difficult to price. However, the 

value of some of these benefits may be captured in the property values of the land 

on which trees stand.

To estimate the value of these “other” benefits, we applied results of research 

that compared differences in sales prices of houses to statistically quantify the 

difference associated with trees. All else being equal, the difference in sales price 

reflects the willingness of buyers to pay for the benefits and costs associated with 

trees. This approach has the virtue of capturing in the sales price both the benefits 
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GENERAL TECHNICAL REPORT PSW-GTR-205 

and costs of trees as perceived by the buyers. Limitations to this approach include 

difficulty determining the value of individual trees on a property, the need to 

extrapolate results from studies done years ago, and the need to extrapolate results 

from front-yard trees on residential properties to trees in other locations (e.g., back 

yards, streets, parks, and nonresidential land).

Anderson and Cordell (1988) surveyed 844 single-family residences in Athens, 

Georgia, and found that each large front-yard tree was associated with a 0.88 

percent increase in the average home sales price. This percentage of sales price was 

used as an indicator of the additional value a resident in the Interior West region 

would gain from selling a home with a large tree.

By averaging the values for several cities in the region, we calculated the average median home price for interior West communities as $144,660. Therefore, the 

value of a large tree that added 0.88 percent to the sales price of such a home was 

$1,276. To estimate annual benefits, the total added value was divided by the LSA 

of a 30-year-old white ash ($1,276/3,557 ft2) to yield the base value of LSA, $0.36 

per ft2. This value was multiplied by the amount of LSA added to the tree during 1 

year of growth.

Calculating the aesthetic and other benefits of residential yard trees—

To calculate the base value for a large tree on private residential property, we 

assumed that a 30-year-old white ash in the front yard increased the property sales 

price by $1,393. Approximately 75 percent of all yard trees, however, are in back 

yards (Richards et al. 1984). Lacking specific research findings, it was assumed 

that back-yard trees had 75 percent of the impact on “curb appeal” and sales price 

compared to front-yard trees. The average annual aesthetic and other benefits for a 

tree on private property were, therefore, estimated as $0.21 per ft2 LSA. To estimate 

annual benefits, this value was multiplied by the LSA added to the tree during 1 

year of growth.

Calculating the aesthetic value of a public tree—

The base value of street trees was calculated in the same way as yard trees. However, because street trees may be adjacent to land with little resale potential, an 

adjusted value was calculated. An analysis of street trees in Modesto, California, 

sampled from aerial photographs (sample size 8 percent of street trees), found 

that 15 percent were located adjacent to nonresidential or commercial property 

(McPherson et al. 1999a). We assumed that 33 percent of these trees—or 5 percent 

of the entire street-tree population—produced no benefits associated with property 

value increases.

Additionally, not all street trees are as effective as front-yard trees in increasing 
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

101

property values. For example, trees adjacent to multifamily housing units will not 

increase the property value at the same rate as trees in front of single-family homes. 

Therefore, a citywide street tree reduction factor (0.73) was applied to prorate trees’ 

value based on the assumption that trees adjacent to different land uses make different contributions to property sales prices. For this analysis, the street reduction 

factor reflects the distribution of street trees in Albuquerque by land use. Reduction factors were single-home residential (100 percent), multihome residential (70 

percent), small commercial (66 percent), industrial/institutional/large commercial 

(40 percent), park/vacant/other (40 percent) (Gonzales 2004, McPherson 2001).

Although the impact of parks on real estate values has been reported (Hammer 

et al. 1974, Schroeder 1982, Tyrvainen 1999), to our knowledge, the onsite and 

external benefits of park trees alone have not been isolated (More et al. 1988). After 

reviewing the literature and recognizing an absence of data, we made the conservative estimate that park trees had half the impact on property prices of street trees. 

Given these assumptions, typical large street and park trees were estimated to 

increase property values by $0.26 and $0.18 per ft2 LSA, respectively. Assuming 

that 80 percent of all municipal trees were on streets and 20 percent in parks, a 

weighted average benefit of $0.245 per ft2 LSA was calculated for each tree.

Calculating Costs

Tree management costs were estimated based on surveys with municipal foresters 

from Albuquerque, New Mexico; Sandy City, Utah; and Logan, Utah. In addition, 

commercial arborists in Salt Lake City, Utah; Austin, Texas; Logan, Utah; and El 

Prado, New Mexico, provided information on tree management costs on residential properties.

Planting

Planting costs include the cost of the tree and the cost for planting, staking, and 

mulching the tree. Based on our survey of Interior West municipal and commercial arborists, planting costs ranged widely and depended mostly on tree size. 

Costs ranged from $85 for a 10-gal tree to $300 for a 2-in tree. In this analysis, we 

assumed that a 15-gal yard tree was planted at a cost of $150. The cost for planting 

a 2-in public tree was $150. 

Pruning

Pruning costs for public trees—

After studying data from municipal forestry programs and their contractors, we 

assumed that young public trees were inspected and pruned once every 3 years 
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during the first 5 years after planting, at a cost of $7 per tree. After this training 

period, pruning occurred once every 5 years for small trees (< 20 ft tall) at a cost 

of $12.50 per tree. Medium trees (20 to 40 ft tall) and large trees (> 40 ft tall) were 

inspected/pruned every 8 years. More expensive equipment and more time was 

required to prune medium ($32.50 per tree) and large trees ($155 per tree) than 

small trees. After factoring in pruning frequency, annualized costs were $2.31, 

$2.50, $4.23, and $20.15 per tree for public young, small, medium, and large trees, 

respectively. Conifers require pruning much less frequently; the average annualized 

cost was $3.32.

Pruning costs for yard trees—

Based on findings from our survey of commercial arborists in the Interior West 

region, pruning cycles for yard trees were about the same as public trees, but only 

about 20 percent of all private trees were professionally pruned (contract rate). 

However, the number of professionally pruned trees grows as the trees grow. We 

assumed that professionals are paid to prune all large trees, 60 percent of the 

medium trees, and only 6 percent of the small and young trees and conifers (Summit and McPherson 1998). Using these contract rates, along with average pruning 

prices ($30, $50, $160, and $300 for young, small, medium, and large trees, respectively), the average annual costs for pruning a yard tree were $0.12, $0.12, $3.84, 

and $7.80 for young, small, medium, and large trees, respectively. The annualized 

cost for pruning conifers was $1.69.

Tree and Stump Removal

The costs for tree removal and disposal were $18 per in d.b.h. for public trees, and 

$25 per in d.b.h. for yard trees. Stump removal costs were $5 per in d.b.h. for public 

trees and $2.50 per in d.b.h. for yard trees. Therefore, total costs for removal and 

disposal of trees and stumps were $23 per in d.b.h. for public trees, and $27.50 per 

in d.b.h. for yard trees. Removal costs of trees under 3 inches in diameter were 

$18.25 and $30 for yard and public trees, respectively.

Pest and Disease Control

Pest and disease control measures in the Interior West are minimal. No city surveyed included costs for pest and disease control in its budget. Results of our commercial arborists’ survey indicated that only 1 percent of all yard trees were treated, 

therefore, no costs for pest and disease control were included.

Irrigation Costs

Costs for watering during the critical 5-year establishment period were estimated 
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

103

at $1.025 per tree per year for public trees and $1.17 per tree per year for yard trees, 

mainly for the labor costs involved in visiting the trees with a water truck or other 

time-intensive method. Beyond the establishment period, it is assumed that trees 

have been planted into irrigated landscapes and therefore the cost of additional 

water for the trees is negligible. 

Other Costs for Public and Yard Trees

Other costs associated with the management of trees include expenditures for infrastructure repair/root pruning, leaf-litter cleanup, and inspection/administration. 

Infrastructure conflict costs—

As trees and sidewalks age, roots can cause damage to sidewalks, curbs, paving, and sewer lines. Sidewalk repair is typically one of the largest expenses for 

public trees (McPherson and Peper 1995). Infrastructure-related expenditures for 

public trees in Interior West communities were approximately $1.50 per tree on an 

annual basis. Roots from most trees in yards do not damage sidewalks and sewers. 

Therefore, the cost for yard trees was estimated to be only 10 percent of the cost for 

public trees.

Litter and storm cleanup costs—

The average annual per-tree cost for litter cleanup (i.e., street sweeping, stormdamage cleanup) was $0.27 per tree ($0.0034 per in d.b.h.). This value was based 

on average annual litter cleanup costs and storm cleanup, assuming a large storm 

results in extraordinary costs about once a decade. Because most residential yard 

trees are not littering the streets with leaves, it was assumed that cleanup costs for 

yard trees were 10 percent of those for public trees.

Inspection and administration costs—

Municipal tree programs have administrative costs for salaries of supervisors and 

clerical staff, operating costs, and overhead. Our survey found that the average 

annual cost for inspection and administration associated with street- and park-tree 

management was $3 per tree ($0.375 per in d.b.h.). Trees on private property do not 

accrue this expense.

Calculating Net Benefits

Benefits Accrue at Different Scales—

When calculating net benefits, it is important to recognize that trees produce 

benefits that accrue both on- and offsite. Benefits are realized at four scales: parcel, 

neighborhood, community, and global. For example, property owners with onsite 

trees not only benefit from increased property values, but they may also directly 
104

GENERAL TECHNICAL REPORT PSW-GTR-205 

benefit from improved human health (e.g., reduced exposure to cancer-causing 

ultraviolet radiation) and greater psychological well-being through visual and 

direct contact with plants. However, on the cost side, increased health care may be 

incurred because of nearby trees owing to allergies and respiratory ailments related 

to pollen. We assume that these intangible benefits and costs are reflected in what 

we term “aesthetics and other benefits.”

The property owner can obtain additional economic benefits from onsite trees 

depending on their location and condition. For example, carefully located onsite 

trees can provide air-conditioning savings by shading windows and walls and 

cooling building microclimates. This benefit can extend to adjacent neighbors who 

benefit from shade and air-temperature reductions that lower their cooling costs.

Neighborhood attractiveness and property values can be influenced by the 

extent of tree canopy cover on individual properties. At the community scale, 

benefits are realized through cleaner air and water, as well as social, educational, 

and employment and job training benefits that can reduce costs for health care, 

welfare, crime prevention, and other social service programs.

Reductions in atmospheric CO2 concentrations owing to trees are an example of 

benefits that are realized at the global scale.

Annual benefits are calculated as:

B = E + AQ + CO2 + H + A where

E = value of net annual energy savings (cooling and heating)

AQ = value of annual air-quality improvement (pollutant uptake, reduced power 

plant emissions, and BVOC emissions)

CO2 = value of annual CO2 reductions (sequestration, reduced emissions, 

release during tree care and decomposition)

H = value of annual stormwater-runoff reductions

A = value of annual aesthetics and other benefits

On the other side of the benefit-cost equation are costs for tree planting and 

management. Expenditures are borne by property owners (irrigation, pruning, and 

removal) and the community (pollen and other health care costs). Annual costs (C) 

are the sum of costs for residential yard trees (CY ) and public trees (CP ) 

where:

CY = P + T + R+ D + I + S + Cl + L

CP = P + T + R + D + I + S + Cl + L + A

where

P = cost of tree and planting
Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting

105

T = average annual tree pruning cost

R = annualized tree and stump removal and disposal cost

D = average annual pest- and disease-control cost

I = annual irrigation cost

S = average annual cost to repair/mitigate infrastructure damage

Cl = annual litter and storm cleanup cost

L = average annual cost for litigation and settlements from tree-related claims

A = annual program administration, inspection, and other costs

Net benefits are calculated as the difference between total benefits and costs:

Net benefits = B–C

Benefit–cost ratios (BCR) are calculated as the ratio of benefits to costs:

BCR = B/C

Limitations of This Study

This analysis does not account for the wide variety of trees planted in Interior West 

communities or their diverse placement. It does not incorporate the full range of 

climatic differences within the region that influence potential energy, air-quality, 

and hydrology benefits. Estimating aesthetics and other benefits is difficult because 

the science in this area is not well developed. We considered only residential and 

municipal tree cost scenarios, but realize that the costs associated with planting 

and managing trees can differ widely depending on program characteristics. For 

example, our analysis does not incorporate costs incurred by utility companies and 

passed on to customers for maintenance of trees under power lines. However, as 

described by examples in chapter 3, local cost data can be substituted for the data in 

this report to evaluate the benefits and costs of alternative programs.

In this analysis, results are presented in terms of future values of benefits and 

costs, not present values. Thus, findings do not incorporate the time value of money 

or inflation. We assume that the user intends to invest in community forests and 

our objective is to identify the relative magnitudes of future costs and benefits. 

If the user is interested in comparing an investment in urban forestry with other 

investment opportunities, it is important to discount all future benefits and costs to 

the beginning of the investment period. For example, trees with a future value of 

$100,000 in 10 years have a present value of $55,840, assuming a 6 percent annual 

interest rate.

This publication is available online at www.fs.fed.us/psw/. You may also order additional 

copies of it by sending your mailing information in label form through one of the following 

means. Please specify the publication title and series number.

Fort Collins Service Center 

Web site http://www.fs.fed.us/psw/

Telephone (970) 498-1392

FAX (970) 498-1122

E-mail rschneider@fs.fed.us

Mailing address Publications Distribution

Rocky Mountain Research Station

240 West Prospect Road

Fort Collins, CO 80526-2098

Pacific Southwest Research Station

800 Buchanan Street

Albany, CA 94710

PSW-GTR-205 Interior West Community Tree Guide: Benefits, Costs, and Strategic Planting