Annual biomass data (2001-2021) for southern California: above- and below-ground, standing dead, and litter

Biomass estimates for shrubland-dominated ecosystems in southern California have, to date, been limited to national or statewide efforts which can underestimate the amount of biomass; are limited to one-time snapshots; or estimate aboveground live biomass only. We developed a consistent, repeatable method to assess four vegetative biomass pools from 2001-2021 for our southern California study area (totaling 6,441,208 ha), defined by the Level IV Ecoregions (Bailey 2016) that intersect with USDA Forest Service lands (Figure 1). We first generated aboveground live biomass estimates (Schrader-Patton and Underwood 2021), and then calculated belowground, standing dead, and litter biomass pools using field data in the peer-reviewed literature (Schrader-Patton et al. 2022) (Figure 2). Over half (52.3%) of the study area is shrubland, and our method accounts for three post-fire shrub regeneration strategies: obligate resprouting, obligate seeding, and facultative seeding shrubs. We also generat..., METHODS
We generated spatial estimates of above ground live biomass (AGLBM, in kg/m2) for 2000-2021 for our southern California study area. The study area, totaling 6,441,208 ha, 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 (Figure 1).
We created biomass raster layers (30m spatial resolution) by modeling a set of covariates (Normalized Difference Vegetation Index [NDVI], precipitation, solar radiation, actual evapotranspiration, aspect, slope, climatic water deficit, elevation, flow accumulation, landscape facets, hydrological recharge and runoff, and soil type) to predict AGLBM using 766 field plots of biomass from the USDA Forest Service Forest Inventory and Analysis (FIA); the Landfire Reference Database (LFRDB) plot data; and other research plots. The dates of field data spanned 2001-2012. The NDVI raster data were derived from Landsat TM/ETM+/OLI multispectral sate..., USAGE NOTES
The biomass raster layers are packaged in zip files for each year using the following naming structure:
WWETAC_UCD_SoCal_Biomass_XXXX.zip
Where XXXX is the year of the biomass estimates. Within each zip file are the following files:
WWETAC_UCD_ <biomass pool>_XXXX_g_m2.tif
Where <biomass pool> is either aboveground, standing dead, litter, or belowground and XXXX designates the year. The dimensions of the geotiff raster files is 21243 columns by 13618 rows and the bounding box coordinates are 36.79, -121.96 (upper left) and 32.47, -115.23 (lower right), in decimal degrees. The rasters are unprojected and in the WGS84 (WKID 4326) geographic coordinate system (decimal degrees). Pixel size is .000317 x .000317 decimal degrees, approximately 35m x 29m depending on latitude.
Intended users of this dataset include resource managers, researchers who are carrying out biogeographic studies, and people needing vegetation biomass estimates across this landscape.
This dataset...