Summary 



A framework for an ecological land classification system 

 for the United States has been described. Land, within 

 the context of this framework, is the conterminous United 

 States, Alaska, Hawaii, and its territorial possessions. 



The system defines potential natural vegetation 

 according to modern ecological principles and patterned 

 after UNESCO (1973) and existing vegetation which are 

 serai (secondary successional) plant communities; soils 

 based on So/7 Taxonomy (USDA, Soil Conservation Sur- 

 vey, 1975); wetlands and deepwater habitats from Cow- 

 ardin and others (1979) as an initial system to characterize 

 wet habitats, including linkage to the vegetation and soil 



elements; and landforms for describing the setting of 

 areas regardless of size, particularly vegetation and soils 

 or vegetation or soil areas. It then describes the integra- 

 tion or combination of elements to form ecological units 

 and combinations of ecological units into spatially re- 

 lated geographic areas. 



A few examples are presented for each level of each 

 element and for the combined or integrated elements. 

 The lowest levels of each element are continually being 

 described, defined, and refined. The classification frame- 

 work can be revised as new information becomes available. 



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