Researchers at the U.S. Forest Service Southern Research Station have utilized the National Land Cover Database (NLCD) to calculate a suite of land cover and forest fragmentation metrics at landscape scales. These datasets yield rich spatial information about urbanization, its effects on forests, and how urban areas interface and mix with rural, agricultural, and forest landscapes.The Forest Area Density (FDEN) map (Landscape Forest Density) illustrates the proportion of the landscape around a given forest area that is also forested. Areas with low forest density may be fragmented by agricultural land use and/or urban and exurban development. FDEN map is colored according to the amount of other forest in a surrounding 15-hectare neighborhood (approximately 37 acres). A place that is not itself forest is colored gray, and a place that is outside the continental United States is colored white. The color of a forest place ranges from red (small amount of forest in the neighborhood) to green (large amount of forest in the neighborhood), with intermediate colors (yellow) indicating forest with intermediate amounts of forest in the neighborhood.
For more information: http://www.forestthreats.org/research/tools/landcover-maps/fden