Green Infrastructure Issue Areas: Urban Forestry

Urban Forestry:

Green infrastructure strategies frequently entail planting trees and vegetation. Trees provide a number of environmental benefits, including reducing ambient levels of carbon dioxide, creating wildlife habitat, filtering and absorbing stormwater runoff, and improving water quality. Trees naturally store and direct water into the soil through their trunks and roots and transpire water back into the atmosphere, relieving some of the pressure on traditional stormwater management systems. Trees also moderate temperatures and save energy. According to a triple bottom line assessment study conducted by the City of Philadelphia, a ten percent increase in tree vegetation can provide a temperature reduction of up to 0.70F.

In addition to the numerous environmental benefits, trees also offer economic benefits, such as increasing property value. The U.S. Environmental Protection Agency (EPA) reported that in Philadelphia, a green retrofit program that converted unsightly abandoned lots into “clean & green” landscapes resulted in economic impacts that exceeded expectations. The report calculated that vacant land improvements led to an increase in surrounding housing values by as much as 30 percent. This translated to a $4 million gain in property values through tree plantings and a $12 million gain through lot improvements.

Green infrastructure techniques can also support the growth and implementation of healthy urban, suburban and rural tree canopies. For example, according to the U.S. Department of Agriculture Forest Service, using the green infrastructure technique of structural soils, which provide space for tree roots to grow under paved surfaces but can still support the weight of cars, can increase the porosity of the area by 30 to 35 percent. Here the tree canopy is increased, so runoff is lower, water storage happens under the pavement, and water quality is improved compared to direct runoff.

For more information about Federal Agencies that utilize green infrastructure urban forestry techniques, visit the U.S. Department of Energy, the U.S. Department of the Interior, and the U.S. Department of Agriculture’s green infrastructure toolkit webpages.

The organizations and reports referenced above and how green infrastructure relates to urban forestry can be found in the following resources:

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