Structure of the NHFEU

The National Hierarchical Framework of Ecological Units (NHFEU) is a hierarchical ecological land classification system. Ecological units are identified and differentiated based on unique combinations of physical and biological characteristics, which may include climate, geology, geomorphology, soils, hydrology, or potential natural vegetation.

Ecological units at each spatial scale are nested within the broader scales. Appropriate uses of ecological units vary by scale. The scales used by WDNR are Province, Section, Subsection, and Landtype Association. View a spatial scale table (PDF, 78KB) outlining ecological units, engeral polygon size, map scale range and application.