Distribution of Above Ground Live Biomass in Vegetation Type Categories - Tree

This dataset consists of 5 raster files of the proportion of above ground live biomass in these vegetation type categories: (1) Shrub obligate resprouting; (2) Shrub obligate seeding; (3) Shrub facultative seeding; (4) Tree; and (5) Herb. The spatial extent of these data cover 6,441,208 ha and is defined by the 42 Level IV Ecoregions (Bailey 2016) that intersect the four southern US Department of Agriculture (USDA) National Forests in southern California (Angeles, Cleveland, Los Padres, and San Bernardino):

Mediterranean-climate region (MCR) shrublands have evolved a set of regeneration strategies in response to periodic, high-intensity wildfires: obligate seeding (OS), obligate resprouting (OR), and facultative seeding (FS) species. Spatial variation is seen in different regeneration strategies. In California, previous studies have found a higher abundance of OR species in mesic environments and OS species in xeric environments).

Analyzing the spatial rasters depicting OS-, OR- or FS- dominated pixels, researchers found dramatically different spatial patterns between the three shrub regeneration strategies. FS species covered the greatest spatial distribution, accounting for 3,372,125 ha (71%) of shrub dominated pixels in the study area: the FS group covered a range of productivity gradients and vegetation types, although it was notably absent from high elevation areas. In contrast, OS-dominated pixels covered the smallest spatial area (21,899 ha, 5% of shrub dominated pixels) occurring throughout the study area from coastal Big Sur and the Santa Ynez Mountains on the Los Padres National Forest to interior locations including the eastern fringes of the San Jacinto mountains (desert shrub vegetation) in the south. Finally, pixels dominated by OR species covered a similarly small area, 25,075 ha (5% of shrub dominated pixels in the study area), showing aggregations in the San Bernardino and San Gorgonio Mountains on the San Bernardino National Forest; San Gabriel Mountains on the Angeles National Forest, and throughout higher elevations on the Los Padres National Forest. OR-dominated pixels were notably absent in lower elevation areas with low water availability, as indicated in the relationship with climatic water deficit and solar radiation. The proportion of each post-fire shrub regeneration type is critical for a number of reasons, including assessing the ability of shrublands to recover from multiple, short- interval fires or helping to prioritize areas for post-fire restoration.