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Data Products ›› Updated Products ››
Rapid Refresh Existing Vegetation Type
The Existing Vegetation Type (EVT) layer represents the vegetation currently present at a given site. LANDFIRE vegetation map units are derived from NatureServe’s Ecological Systems classification, which is a nationally consistent set of mid-scale ecological units (Comer and others 2003). Existing vegetation is mapped through a predictive modeling approach using a combination of field reference information, Landsat imagery, and spatially explicit biophysical gradient data. Field data keyed to dominant vegetation type at the plot level were used as "training data" to drive the modeling process. Attribute information is provided that links the LANDFIRE EVT map units to existing classifications such as the National Vegetation Classification System and those of the Society of American Foresters and Society of Range Management.
The LANDFIRE Existing Vegetation Type data layer has been updated for western zones based upon the burn severity of recent (1999 to 2007) wildland fires. (Obtain Rapid Refresh Fire Perimeter Data.) In general, it was assumed that existing vegetation types would potentially change only when influenced by moderate or high-severity fires. Furthermore, the original LANDFIRE fuel layers incorporated additional areas classified as barren and water that were not incorporated into the vegetation layers. In the Rapid Refresh process, these areas of barren and water were added to the existing vegetation layers to better reflect what is on the ground and to ensure that the vegetation and fuel layers are logically consistent.
Link to Ecological Systems descriptions for LANDFIRE vegetation map product legends.
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