Calculator Shows Trees Do Pay Off
Posted: December 18, 2011Source: The Times Leader
Photo compliments of: Big Sky Country Photos
What do trees have to do with energy? Trees and otherplants are energy.
They are the ultimate collectors of solar energy, using the energy of the sun to produce food through photosynthesis. Plants jump-start the entire food chain with this energy, synthesizing carbon-based food by taking carbon dioxide and water and that energy from the sun and producing carbohydrates for their own metabolism. In turn, this food feeds animals such as us, or animals that eat animals that ultimately ate plants.
Second, trees are leafy friends that pay us back by conserving energy in our homes. For example, according to treebenefits.com, a 30-inch diameter pin oak in my yard provides $371 in annual benefits in terms of stormwater remediation, air-quality benefits, carbon sequestration, enhanced property value and energy savings. According to estimates of the Tree Benefit Calculator and the i-Tree suite of software (itreetools.org), those energy benefits for this one tree include estimated savings of 362 kilowatt-hours of electricity and reduced consumption of oil or natural gas by 49 therms. The estimated value of these benefits from this one tree is $75 a year.
How so? According to treebenefits.com, trees modify climate and conserve building energy use in three principal ways:
• Shading reduces the amount of heat absorbed and stored by buildings.
• Evapotranspiration converts water to vapor and cools the air by using solar energy that would otherwise result in heating the air.
• Tree canopies slow down winds, thereby reducing the amount of heat lost from a home, especially where conductivity is high (e.g., glass windows).
Strategically placed trees can increase home energy efficiency. In summer, trees shading east and west walls keep buildings cooler. In winter, allowing the sun to strike the southern side of a building can warm interior spaces. If southern walls are shaded by dense evergreen trees, there may be a resultant increase in winter heating costs.
Check out the Tree Benefits Calculator for trees in your yard, your business or your school. It was developed by the Davey Tree Expert Co. of Kent, Ohio, and the Casey Tree Foundation in Washington, D.C. They developed this simple-to-use tool from research that is continually improving the models that are collectively known as the i-Tree suite of software. The i-Tree software is a partnership of the U.S. Forest Service, the National Arbor Day Foundation, the International Society of Arboriculture and the Davey Tree Expert Co.
To use the Tree Benefits Calculator for an estimate of the economic value of the environmental services your tree or trees provide, you need the ZIP code of the tree’s location (Arizona is different from Ohio), the tree species (a drop-down menu), a measurement or estimate of the diameter of the tree and a bit more about its location (for example, whether it is in front of a home or in parkland). Direct energy savings relative to heating and cooling a house differ if the tree is in your yard or in a park.
As noted at the treebenefits.com website: “The Tree Benefit Calculator is intended to be simple and accessible. As such, this tool should be considered a starting point for understanding trees’ value in the community, rather than a scientific accounting of precise values. For more detailed information on urban and community forest assessments, visit the i-Tree website.”