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. 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
One of the greatest challenges facing public power today is environmental stewardship. 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. 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. APPA and SMUD have registered the Tree Benefits Estimator with the Library of Congress and reserve all rights to it.
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 whether the utility has a substantial summer cooling load (which would then estimate 100% of the energy and capacity benefits), or small summer cooling load (which would then estimate 50% of the energy and capacity benefits) or no summer cooling load (which would then provide no energy and capacity benefits). However, regardless of whether a utility has any summer cooling load, the method will estimate carbon and CO2 sequestration values for the specified tree species.
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.
The age of the tree from the planting date will then determine the tree growth rate factor and the tree survival rate factor, which will in turn determine together the level of benefits for any year between 1 and 30. In other words, 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.
|
 |
The estimator was developed by Sacramento Municipal Utility District (SMUD) as part of APPA's TREE POWER Program 
Need More Help?
For technical assistance with the estimator, please contact Misha Sarkovich, Ph.D., Project Manager, SMUD. |
