from

http://www.nsf.gov/index.jsp

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http://www.nsf.gov/news/mmg/mmg_disp.cfm?med_id=57015&from=googlebot(at)google.com

A Landsat Thematic Mapper satellite image from 2002 showing land cover for central Puget Sound in Washington state. [Legend: Dense Urban (75% Impervious Surface--Black); light-medium urban area (10-75% impervious surface--red); agriculture/grass (brown); mixed and deciduous forest (light green); coniferous forest (dark green); wetlands (light green); shoreline (gray); water (blue).] (Date of Image: June 2002) The University of Washington's Urban Ecology Project seeks to better understand the ways in which humans interact with their environment and apply that knowledge effectively. The project is an interdisciplinary research and education effort involving a large number of faculty, staff and students from a variety of departments, as well as members of government, industry and policy-makers, and is being supported under the National Science Foundation's Integrative Graduate Education and Research Traineeship (IGERT) program. For more information on the Urban Ecology Project and current research projects taking place, visit their Web site at http://www.urbanecology.washington.edu/index.html.
Credit: Jeffrey Hepinstall, Urban Ecology Research Laboratory, Department of Urban Design and Planning, University of Washington

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Before and after GIS satellite images of the Puget Sound area in Washington show that vegetation and tree cover (lighter color) in 1972 declined as urban areas (dark color) increased by 1996. The urban areas have less than 20 percent tree cover.

from

http://www.epa.gov/globalwarming/greenhouse/greenhouse7/trees.html

Solution and Results
Raw satellite data can be analyzed using ERDAS IMAGINE software and IMAGINE Subpixel Classifier to determine eight categories of tree cover and one category of less than 20% tree cover. Green areas are at one end of this spectrum representing tree cover over 50%; urban areas are black. Citizens from Bellevue used these images along with CITYgreen software from American Forests to conduct a detailed analysis of the tree cover in their city.

http://www.discover-aai.com/environmental/landmanagement.htm