The Existing Vegetation Cover (EVC) layer represents the vertically projected percent cover of the live canopy layer for a 30-m grid cell.
EVC is generated separately for tree, shrub and herbaceous cover lifeforms using training data and other layers. Percentage tree, shrub, and herbaceous canopy cover training data are generated using plot-level ground-based visual assessments. Once the training data are developed, relationships are then established separately for each lifeform between the training data and combination of Landsat, elevation, and ancillary data. Each of the derived data layers (tree, shrub, herbaceous) has a potential range from 0-100 percent which are merged into a single composite EVC layer.
LANDFIRE (LF) uses EVC in several subsequent layers, including the development of the fuel layers.