In the context of RAVG analysis, broad vegetation classes used for spatial analysis of burned area. The RAVG vegetation groups are based on the LANDFIRE Existing Vegetation Types (EVT) dataset, which provides a consistent national classification system to produce uniform statistics from vegetation cover data at the national level. Crosswalks to RAVG vegetation groups were developed from LANDFIRE Existing Vegetation Type Descriptions, Forest Types of the United States, Society of American Foresters forest cover types, Society for Range Management rangeland cover types, and the National Vegetation Classification Standard (NVCS). LANDFIRE Existing Vegetation Cover (EVC) data were used to inform the canopy closure aspect (closed canopy, open canopy or non-tree). The eight RAVG vegetation groups are defined as follows:
- Deciduous Open Tree Canopy - Open canopy dominated by deciduous tree species, with deciduous species contributing more than 75% of the total tree cover.
- Deciduous Closed Tree Canopy - Closed tree canopy dominated by deciduous tree species, with deciduous species contributing more than 75% of the total tree cover.
- Evergreen Open Tree Canopy - Open canopy dominated by evergreen tree species, with evergreen species contributing more than 75% of the total tree cover.
- Evergreen Closed Tree Canopy - Closed tree canopy dominated by evergreen tree species, with evergreen species contributing more than 75% of the total tree cover.
- Mixed Evergreen-Deciduous Open Tree Canopy - Open canopy dominated by a combination of evergreen and deciduous tree species, with each contributing 25 to 75% of the total tree cover.
- Mixed Evergreen-Deciduous Closed Tree Canopy - Closed tree canopy dominated by a combination of evergreen and deciduous tree species, with each contributing 25 to 75% of the total tree cover.
- Pinyon-Juniper Woodland - Area dominated by open stands of Pinus edulis (pinyon) and Juniperous menosperma (juniper). The total canopy cover is generally 25 to 60% but may be less than 25%. This vegetation group is found in the southwestern portion of the United States.
- Grassland / Shrubland / Non-Vegetation - All conditions not dominated by trees. Grasslands are dominated by herbaceous plants (generally forming at least 25% cover) with trees, shrubs, and dwarf shrubs accounting for less than 25% of total vegetation. Shrubland includes areas where the shrub component is generally greater than 0.5 meters tall with individuals or clumps overlapping but not touching. Non-vegetation describes areas completely bare of vegetation, like rock outcrops, lava fields, and water bodies.
Forest covers associated with the six deciduous and evergreen groups are described in Forest Cover Types of the United States (Society of American Foresters, F.H. Eyre, Editor, 1980). Many of the vegetation types associated with the non-tree group are described in Rangeland Cover Types of the United States (Thomas N. Shieflet, Editor, Society for Range Management, 1994).