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S_USA.NationalLandcoverSubsections

The National Land Cover Subsections feature class contains ecological subsection polygons attributed with land cover types to show the relationships between ECOMAP 2007 and National Landcover mapping (USGS, 1992). The EcomapSubsections 2007 data set describes the ecological subsections within the conterminous United States. It contains regional geographic delineations for analysis of ecological relationships across ecological units. ECOMAP is the term used for a USDA Forest Service initiative to map ecological units and encourage their use in ecosystem-based approaches to forest land conservation and management. This is a collaborative effort with many partners. It is coordinated at the national and regional levels by USDA Forest Service staff and implemented in cooperation with State forestry agencies and others. ECOMAP mapping criteria are outlined in the National Hierarchical Framework of Ecological Units (https://www.ncrs.fs.fed.us/gla/reports/hierarchy.htm). The framework systematically divides the country into progressively smaller areas of land and water that have similar physical and biological characteristics and ecological processes.