The LANDFIRE existing vegetation layers describe the following elements of existing vegetation for each LANDFIRE mapping zone: existing vegetation type, existing vegetation canopy cover, and existing vegetation height. Vegetation is mapped using predictive landscape models based on extensive field reference data, satellite imagery, biophysical gradient layers, and classification and regression trees. DATA SUMMARY: The existing vegetation height (EVH) data layer is an important input to LANDFIRE modeling efforts. Canopy height is generated separately for tree, shrub and herbaceous cover life forms using training data and a series of geospatial data layers. EVH is determined by the average height weighted by species cover and based on existing vegetation type (EVT) life-form assignments. Dominant life-form height of each plot is then binned as follows: (A) Tree classes; 0-5 m, 5-10 m, 10-25 m, 25-50 m, and greater than 50 m, (B) Shrub classes; 0-0.5 m, 0.5-1.0 m, 1.0-3.0 m, greater than 3.0 m, (C) Herbaceous vegetation classes; 0-0.5 m; 0.5-1.0 m, greater than 1 m. Decision tree models using field reference data and Landsat imagery, digital elevation model data, and biophysical gradient data, are then developed separately for each of the three life forms using C5 software. Life-form specific cross-validation error matrices are generated during this process to assess levels of accuracy of the models. Decision tree relationships are then used to generate life-form specific height class spatial data layers, which are later merged into a single composite height data layer. The final EVH layer is evaluated and rectified through a series of QA/QC measures to ensure that the life-form of the cover code matched the life-form of the existing vegetation type. EVH is used in many subsequent LANDFIRE data layers. Refer to spatial metadata for date ranges of field plot data and satellite imagery for each LANDFIRE map zone.