LANDFIRE's (LF) 2023 update (LF 2023) Existing Vegetation Height (EVH) represents the average height of the dominant vegetation for a 30-m cell. EVH is produced separately for tree, shrub, and herbaceous lifeforms using training data depicting the weighted average height by species cover and Existing Vegetation Type (EVT) lifeform. Decision tree models using field reference data, lidar, and Landsat are developed separately for each lifeform, then lifeform specific height class layers are merged along with land cover into a single EVH product based on the dominant lifeform of each pixel. EVH ranges are continuous for the herbaceous lifeform category ranging from 0.1 to 1 meter with decimeter increments, 0.1 to 3 meters for shrub lifeform, and 1 to 99 meters for tree lifeform. If the height values of each lifeform exceed the continuous value range, they are binned into the appropriate maximum height class. EVH is then reconciled through QA/QC measures to ensure lifeform is synchronized with Existing Vegetation Cover (EVC).
In Alaska, developed and agricultural lands were derived from the National Land Cover Database (NLCD) 2016 Land Cover. Roads were derived from the NLCD 2016 Developed Urban Descriptor for south-central Alaska and a state-wide dataset from HERE Technologies. In the Alaska 90km buffer area developed and agricultural lands were derived from the North American Land Change Monitoring System ((NALCMS) https://www.mrlc.gov/data/north-american-land-change-monitoring-system) 2015 Land Cover and new developed lands were added from the NALCMS 2020 Land Cover for LF 2023. Disturbance events after 2016 are accounted for by incorporating transition rulesets using LF 2023 Fuel Disturbance (FDist). LF uses EVH as an input for LF 2023 Fuel Vegetation Height (FVH).