Project-level Application of the Forest Service Hierarchical Ecological Classification System

Research Issue

The Forest Service developed an eight-level ecological-based classification system in the early 1990s for agency uses ranging from national, regional, forest, and district administrative levels. In 1995, the classification system was used to produce a consistent map of ecoregions of the US (see figure below). Those mapped ecoregions were used as the basis for developing tree growth models for the Southern Variant of the Forest Vegetation Simulator. Following evaluation and review, the 1995 ecoregion map was updated and revised in 2007.

Ecoregions of the United States Provinces

Ecoregions of the United States Provinces

The five upper levels (national and regional applications) have been used as a basis of ecosystem classification for a number of purposes including national wildland fuel models, regional resource assessments, climate change evaluations, and selection of research natural areas. The lower three levels are intended for uses at the national forest and ranger district levels, but have not been tested and evaluated for applications under operational conditions in the South. Testing and evaluation of the lower levels of the hierarchy are needed by national forest service planners to provide a sound foundation on which to make resource management decisions that will be accepted by the public.

Our Research

Results from this series of projects differ from traditional research in that hypotheses were not formulated and tested. Instead, a small group of "experts" at the national (Washington Office, Regions, Stations) and local (National Forests, Ranger Districts) administrative levels collaborated to delineate, review, and revise ecological units based on collective knowledge. Testing proposed ecological units is necessary to demonstrate validity of the map, but is difficult because adequate data sets are lacking, particularly for units that are regional in extent. Working alone at the regional scale and with national forest cooperators at the local scale, we have made several tests of mapped ecounits to develop methods and demonstrate feasibility of additional testing and evaluation by others.

Expected Outcomes

Products of this work consist of maps of ecological units delineated at a range of scales, accompanied by descriptions of the map units. Users representing a range of disciplines use the maps for a range of projects and report on their findings in publications, which then form the basis for future revisions of the mapped ecoregions.

Research Results

  • Cleland, D.T., Freeouf, J.A., Keys, J.E., Nowacki, G.J., Carpenter, C.A., and McNab, W.H. 2007. Ecological subregions: Sections and subsections of the conterminous United States. General Technical Report WO-70. Washington, DC: U.S. Department of Agriculture, Forest Service. [Issued as a CD only]
  • McNab, W.H.; Lloyd, F.T. 2009. Testing ecoregions in Kentucky and Tennessee with satellite imagery and Forest Inventory data. In: McWilliams, Will; Moisen, Gretchen; Czaplewski, Ray, comps. Forest Inventory and Anslysis (FIA) Symposium 2008; October 21-23, 2008; Park City, UT. Proc. RMRS-P-56CD. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Reserch Station. 19 p.
  • McNab, W.H.; Keyser, C.E. 2011. Revisions to the 1995 map of ecological subregions that affect users of the southern variant of the Forest Vegetation Simulator. e-Research Note SRS-RN-21. Asheville, NC: USDA, Forest Service, Southern Research Station, 4 p.
  • McNab, W.H.; Stephens, R.B.; Rightmyer, R.D.; Mavity, E.M.; Lambert, S.G. 2012. A preliminary test of an ecological classification system for the Oconee National Forest using forest inventory and analysis data. In: McWilliams, Will.; Roesch, F.A. eds. 2012. Monitoring Across Borders: 2010 Joint Meeting of the Forest Inventory and Analysis (FIA) Symposium and the Southern Mensurationists. e-Gen. Tech. Rep. SRS-157. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. p. 77-86.
  • McNab, W.H.; Stephens, R.B.; Rightmyer, R.D.; Mavity, E.M.; [and 6 other coauthors]. (In prep.) Development of an Ecological Classification System for the Cooper Creek Watershed of the Chattahoochee National Forest: A First Approximation. In: Haywood, Dave; Holley, Gordon. eds. Proceedings of the 17th Biennial Southern Silviculture Research Conference. March 5-7, 2013. Shreveport, LA. e-Gen. Tech. Rep. SRS-XXX. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station. P. xxx-xxx. [Poster has been accepted for presentation, which will be the basis for a manuscript and paper in the conference proceedings.]

Research Partners and Collaborators

  • WO, RO, NRS (for national ecoregion map)
  • Oconee National Forest
  • Chattahoochee National Forest
  • Forest Inventory and Analysis