Landtype Associations for Wyoming

The data-set includes Landtype Associations as well as higher hierarchical units in which Landtype Associations are imbedded. Landtype Associations are defined by ECOMAP (1993) as units at the landscape scale as follows: groupings of Landtypes or subdivisions of Subsections based upon similarities in geomorphic process, geological rock types, soil complexes, stream types, lakes, wetlands, and series, subseries, or plant association vegetation communities.

Repeatable patterns of soil complexes and plant communities are useful in delineating map units at this level. Names of Landtype Associations are often derived from geomorphic history and vegetation community. Mountainous terrain was delineated only at the higher subsection level as finer sub-divisions are the purview of the U.S. Forest Service.

The dataset is available in four different regions of Wyoming, compiled during different time periods and using different methods. Southeast Wyoming was compiled in 1996. Southwest Wyoming and a portion of Northeast Wyoming was compiled in 1997.

In 1999, two more regions were compiled (Northwest and Buffalo Resource Area, NorthCentral) using different methods. Landtype associations delineated in 1996 and 1997 were based on a subjective process. The subsequent mapping of northwest Wyoming and the Buffalo Resource area was based on a different delineation process, using a terrain characterization process based on empirical analysis modified from Hammond (1964).

Details of methods used are provided in the report: W.A. Reiners, Axtmann E.V., and R.C. Thurston. 1999. Delineations of Landtype Associations for Northwest Wyoming and the Buffalo Resource Area. Bureau of Land Management/University of Wyoming.