Quantifying Public Power’sEnvironmental Contributions:

Tree Benefits EstimatorAPPA National Conference, June 20, 2005

Misha Sarkovich, Ph.D.Program Manager

(916) 732-6484Fax (916) 732-5695

E-mail:Misha.Sarkovich@SMUD.org

“If you ask me a question I don't know, I'm not going to answer” Yogi Berra

Tree Benefits Estimator• The APPA Tree Benefits Estimator Was Designed to

Help You• This Web-based application will help APPA member

utilities quantify and track the benefits of planting shade trees (www.APPAnet.org)

• It estimates the amount of energy savings (KWh saved), capacity savings (KW saved) and carbon and CO2 sequestration (lbs) resulting from mature trees planted in urban and suburban settings.

• The Tree Benefits Estimator can be used by those who have no formal background in urban forestry or Demand Side Management (DSM) utility practices.

Tracking the Benefits of Tree-Planting Efforts is Necessary

• It is increasingly important that public power utilities not only take steps toward local environmental improvements, but measure the effectiveness of their efforts.

• The measurements are important to local communities in understanding how they can control their environmental future and the cost of doing so.

• It is also important for utilities to be able to measure environmental impacts that in the future may be reported to state and federal governments on a voluntary or mandatory basis.

What You Need to Know About the Estimator

• The Tree Benefit Estimator, developed by Sacramento Municipal Utility District (SMUD), was based on the experience of the SMUD's Shade Tree program.

• In developing this simplified and easy-to-use method for estimating the tree planting benefits, broad assumptions have been made regarding trees' impact on direct shading benefits, impacts of indirect or evapotranspiration effect, heating penalty in winter months, tree growth rates and tree survival rates.

What You Need to Know About the Estimator

• As a result, this method may yield less precise results than a more tailored approach.

• Staff from the Center for Urban Forest Research, Pacific Southwest Research Station, USDA Forest Service, University of California, Davis, have reviewed the Tree Benefits Estimator.

What You Need to Know About Your Trees

1. the tree species;2. the direction your tree faces (for trees

planted next to buildings);3. the distance between the tree and the

building that is being shaded;and, 4. the age of the tree from the tree

planting date.

Items to Consider

• To take into account different climate zones, you will need to input information on the level of the summer cooling load

• If an utility has a substantial summer cooling load, then estimator will provide 100% of the energy and capacity benefits,

• If an utility has a small summer cooling load, then estimator will provide 50% of the energy and capacity benefits. If an utility has no summer cooling load, then estimator will provide no energy and capacity benefits.

• Regardless of whether a utility has any summer cooling load, the method will estimate carbon and CO2 sequestration values.

What You Need to Know About Your Trees

Results

Assumptions:Tree Growth Rate

• The methodology is based on the "standard" nursery raised trees which are typically sold in 5-gallon containers, and which are usually 1 inch in diameter at the tree base (1 foot above the ground).• SMUD Shade Tree program has experienced that 5-gallon container trees will grow quickly and catch up with the larger 15-gallon container trees within the next couple of years and thus the methodology applies for both 5- and 15-gallon container trees. • This methodology assumes that the standard (5 gallon) trees are "0" age when planted.

Tree Growth Rate

Assumptions: Tree Mortality or Tree Survival Rate

• This methodology assumes certain tree survival rate or tree mortality rate for the urban or suburban trees in the next 30 years.

Tree Mortality or Survival Rate

Tree Mortality & Growth Rate Factors Combined

• The age of the tree from the planting date will then determine the tree growth rate factor and the tree survival rate factor.

• The combination of the tree growth rate and the tree survival rate will determine the final multiplier factor that will estimate the appropriate level of tree benefits for any year.

• In order to estimate tree benefits for any tree age (between age 1 to 30 years), you will need to enter the age of the tree from the tree planting date and the estimator will automatically multiply the energy, capacity and carbon sequestration benefit values of MATURE trees with the appropriate Tree Growth and Survival Rate FACTOR. Additional manual calculations are NOT needed.

Tree Mortality & Growth Rate Factor

Ways to Use the Information

1)      Share the results with your community –

• Here's your chance to add solid data to your tree-planting messages.

• If community members can understand how trees really do make a difference in their back yards (and in their parks, schoolyards, and around public buildings) they may be more willing to plant the right trees in the right places and take good care of them.

• Community members will be happy to learn that their utility is doing its part to improve the environment and save them money at the same time.

Ways to Use the Information

2)    Report the numbers to legislators, regulators, board members, etc –

• It is becoming increasingly important to measure the effectiveness of environmental efforts.

• By keeping records of your tree-planting initiatives you can prove to local, state and national officials that you are doing your part to improve the environment.

Ways to Use the Information

3)     Enhance your tree-planting program –

• It is hard to tell if your program is doing what it is suppose to be doing unless you evaluate its progress.

• By using the Tree Benefits Estimator, you can better understand the effects your tree-planting program has in your community.

• Then, you can determine what you need to do next: plant more trees; keep better records; promote your good results to your publics; etc.

SMUD Shade Tree Program

Figu re 1T ota l A verage P resent V alue of B enefits (P V B ) per T ree by T ree O rientation [1 ]

$ 0

$ 2 5

$ 5 0

$ 7 5

$ 1 00

$ 1 25

N N E E SE S SW W N W Average

O rienta tion of T ree from Participant H ou se

Pres

ent V

alue

of B

enef

its p

er T

ree

Shading of A djacent H om es

Shading of Participant H om e

[1 ] B ased on estim ated long-term tree m ortality o f 42 .5 percent over 30-year period fo r trees p lantedunder p rogram in 1991-1993.

SMUD Shade Tree Program

Figure 2Percent of Total Trees Planted and Total Program Benefits by Tree Orientation

0%

10%

20%

30%

40%

50%

60%

N NE E SE S SW W NW

Orientation of Tree from Participant House

Perc

ent o

f Tot

al T

rees

/Ben

efits

Percent of Total Trees

Percent of Total Benefits

SMUD Shade Tree Program

•Figure 3

•What is Allowed Under the 1996 Tree-Siting Guidelines

•LARGE TREES

•NW •N •NE

•W •E

•SW •S •SE

•MEDIUM TREES

•NW •N •NE

•W •E

•SW •S •SE

•SMALL TREES

•NW •N •NE

•W •E

•SW •S •SE

•Shaded sites have higher than the minimum $20 per tree PVB.

SMUD Sacramento Shade

• started in 1990• implemented in collaboration with the local, non-profit,

community based organization (Sacramento Tree Foundation ) -- STF is a contractor

• the program is 100% funded by SMUD• Program provides free trees (5 gallon), stakes, ties,

fertilizers and expert advice (STF)• over 120,000 program participants• over 350,000 trees planted• annual budget over $1.5 million• over $20 million invested since 1990• received several national and state awards

Thank you for making this day necessary. (Yogi Berra )

Lessons LearnedCost effective strategies for SMUDPrograms valued highly by utility customersContinuous program refinements in design &

operationSMUD Board & Management made enduring

commitment to Urban Heat Island mitigation efforts

Involve local trade allies (urban forestry organizations)