Using CITYgreen and High Resolution Multi-Spectral Imagery to Analyze the Urban Ecosystem

Geographic Information Systems (GIS) provides a framework for analyzing the spatial relationships that exist in urban areas among trees, other natural resources, and the built environment. Using GIS, cities now have the tools to map, measure, and quantify the benefits of their urban forests. Collecting, storing, and using data in a GIS about the gray infrastructure, like buildings, roads, and sewer networks, is common in most local governments today. However, spatial information regarding green infrastructure such as, trees, and other vegetation, and their environmental and economic benefits has been absent. Local governments can use this data to make better informed land development and management decisions. The incorporation of high-resolution multispectral satellite and digital aerial imagery enables communities to build a "green data layer,"—a highly accurate representation of their green infrastructure. This data layer can be used in GIS to influence planning, design, and preservation decisions. Using a green data layer, cities can measure their tree cover and set attainable canopy goals so as to put this resource to best ecological use for improving air and water quality. CITYgreen is a GIS software package developed by American Forests as an extension to ESRI's ArcGIS that calculates the services provided to a community by its green infrastructure. The purpose of this paper is to explain the creation of a green data layer and its use in CITYgreen to quantify the benefits of the urban forest.