EcoMap Ecoregions and Subregions of Alaska

This map displays ecosystems of Alaska as determined by the criteria stated in the "National Hierarchical Framework of Ecological Units" (USDA Forest Service 1993).  Within this hierarchical system, ecosystems are delineated at multiple scales using different sets of environmental factors and are successively nested within one another.  Three ecosystem levels are recognized at the Ecoregion scale: Domains, Divisions, and Provinces.  Domains simply represent subcontinental climate zones.  Divisions and Provinces represent climatic subzones as reflected by dominant lifeforms [meadow vs. forest] and broad vegetation types, respectively.  Within the Subregion scale are Sections and  Subsections.  Sections are distinguished mainly by geomorphic and topographic features.  The prefix "M" attached to codes represent mountainous Sections where soil and vegetational zonation is present.