58

S_USA.FennemanJohnsonPhySubsections

The Fenneman-Johnson Physiographic Subsections feature class contains ecological subsection polygons attributed with physiographic types to show the relationships between ECOMAP 2007 and Fenneman-Johnson physiographic mapping from USGS (1946). The EcomapSubsections 2007 data set contains polygons for 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.