2004. United States. Forest Service. This polygon shapefile is commonly called Bailey's ecoregions and shows ecosystems of regional extent in the United States, Puerto Rico, and the U.... National Atlas of the United States.
2002. United States. Forest Service and Geological Survey (U.S.). This raster layer portrays general forest cover types for the United States in GeoTIFF format. Data were derived from Advanced Very High Resolution... National Atlas of the United States.