Using GIS to Assess Urban Tree Canopy Benefits and Surrounding Greenspace Distributions

"CITYgreen™, a geographic information system (GIS)-based program, was used to evaluate selected benefits provided by the tree canopy in the city of Stevens Point, Wisconsin. We assessed the distribution of open space in and around the greater Stevens Point area, energy savings from lowered air-conditioning costs, and the reductions in stormwater runoff as a partial function of existing tree canopy. Estimated annual energy savings for residential areas in Stevens Point and surrounding communities was $126,859. A storm delivering 6.6 cm (2.6 in.) of rain in 24 hours will deposit just under 2 billion L (530 million gal) of water on Stevens Point, of which 400 million L (106 million gal) will run off into the Wisconsin River. Approximately 6% of Stevens Point is covered by impervious surfacing, which accounts for 24% of the city's total stormwater runoff volume. Orthophotographs were digitized on screen, and land surrounding Stevens Point was classified based on vegetation cover, land use, and current zoning. Land use in the greater Stevens Point area (22,250 ha [55, 000 ac]) is 20.7% developed, 24.1% agriculture, 46.8% undeveloped, and 8.4% surface water. Planners, managers, elected officials, and other interested parties in land-use planning for the region are using the results of this study for open-space planning." [Abstract]