Decreasing landscape carbon storage in western US forests with 2˚C of warming
Data files
Dec 08, 2025 version files 2.71 GB
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Conif_HUC12_shapefile-20250804T211205Z-1-001.zip
190.25 MB
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ecoregion_nature_conservancy-20250804T211301Z-1-001.zip
3.76 MB
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LF16_EVT_200_3.csv
287.06 KB
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new_SAF_SRM_2.csv
27.46 KB
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Part1-climate_analog_post_processing.R
50.83 KB
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Part2-plotting_script.R
18.60 KB
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README.md
5.78 KB
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terraclimate_4km_1986_2015_climatevariables.tiff
4.56 MB
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treemap_w_us_crop_classify_4km.tiff
939.92 KB
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treemap_w_us_crop_classify.tiff
2.36 GB
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W_us_AET_annual_1986_2015.tiff
19.64 MB
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W_us_AET_annual_2C_scaled_proj_1986_2015.tiff
13.89 MB
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W_us_CWD_annual_1986_2015.tiff
20.74 MB
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W_us_CWD_annual_2C_scaled_proj_1986_2015.tiff
14.93 MB
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W_us_TMAX_annual_1986_2015.tiff
22.19 MB
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W_us_TMAX_annual_2C_scaled_proj_1986_2015.tiff
16.78 MB
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W_us_TMIN_annual_1986_2015.tiff
23.09 MB
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W_us_TMIN_annual_2C_scaled_proj_1986_2015.tiff
16.70 MB
Abstract
Changing climate is altering the amount of carbon that can be sustained in forest ecosystems. Increasing heat and drought are already causing increased mortality and decreased regeneration in some locations. These changes have implications for landscape carbon storage with ongoing climate change. We used a climate analogs approach to project aboveground forest carbon density under +2 °C warming above the pre-industrial climate for western US forests. We calculated analogs for the current climate and under +2 °C warming and associated carbon density for each time period. We found that in most ecoregions, maximum carbon density values are projected to decline, and the interquartile range of carbon density values is projected to narrow. Using mean carbon density values, we project a 796 Tg decline in landscape carbon storage across the western US. As tree mortality increases, the transition from live to dead carbon will increase fuel buildup and fire hazard in many ecosystems. Greater fire hazard and increased susceptibility to insects from drought could cause carbon density changes to occur more rapidly than our climate-only projections. This may have substantial implications for forest-based carbon offset projects.
Dataset DOI: 10.5061/dryad.1g1jwsv9g
Description of the data and file structure
These data and code are for the manuscript 'Decreasing landscape carbon storage in western US forests with 2˚C of warming'. Data are from publicly available sources, including TerraClimate and TreeMap. The code uses these data to calculate analogs of carbon density under the projected +2 degrees C climate data from TerraClimate.
Usage Notes:
- CSV: Text files storing tabular data where rows represent observations and columns represent variables; viewable in text editors, spreadsheets, or analytical tools like R.
- TIFF/TIF: Spatially referenced raster image files used for landscape data (e.g., vegetation, topography); viewable in GIS software or R.
- SHP: Shapefiles store vector GIS data (points, lines, polygons) for geographic features; require accompanying files (.dbf, .prj, etc.) and can be used in R, Python, or GIS tools.
- R: Script files containing R code for data processing, analysis, and visualization; comments start with
#and are not executed.
Files and variables
File: treemap_w_us_crop_classify.tiff
Description: 30m aboveground forest biomass data in Mg/ha from the TreeMap data set, which was developed by interpolating US Forest Service Forest Inventory and Analysis plot data (https://doi.org/10.2737/RDS-2021-0074).
File: treemap_w_us_crop_classify_4km.tiff
Description: 4km aboveground forest biomass data in Mg/ha. These are the 30m data aggregated to 4km to align with the 4km TerraClimate data.
File: LF16_EVT_200_3.csv
Description: Landfire Existing Vegetation Type data (https://doi.org/10.5066/P1XVKXRL). These data provide the vegetation types associated with the TreeMap data.
Variables
- VALUE: Ecological Systems code used by LANDFIRE
- EVT_NAME: Ecological Systems name in the LANDFIRE EVT legend
- LFRDB: Database value
- EVT_FUEL: Ecological Systems code used for Fuel product development
- EVT_FUEL_N: Ecological Systems class name used for Fuel product development
- EVT_LF: Vegetation lifeform (e.g., Tree, Shrub, Herb, Sparse)
- EVT_PHYS: Vegetation lifeform (e.g., Tree, Shrub, Herb, Sparse)
- EVT_GP: Collapsed vegetation type code
- EVT_GP_N: Collapsed vegetation type name (e.g., Grasslands and Steppes, Hammocks, Longleaf Pine)
- SAF_SRM: Society of American Foresters/Society for Range Management cover type
- SAF_SRM2: Society of American Foresters/Society for Range Management cover type 2
- EVT_ORDER: Vegetation Physiognomic Order (FGDC Classes)
- EVT_CLASS: Vegetation Class (FGDC Classes)
- EVT_SBCLS: Vegetation Subclass (FGDC Classes)
- R: Red color value range/255
- G: Green color value range/255
- B: Blue color value range/255
- RED: Red color value range 0 - 1
- GREEN: Green color value range 0 - 1
- BLUE: Blue color value range 0 - 1
File: new_SAF_SRM_2.csv
Description: This is the forest and rangeland cover classification from the Society of American Foresters and Society for Rangeland Management (https://www.fs.usda.gov/nrm/documents/fsveg/cse_user_guides/R3FG_appendix.pdf).
Variables
- ECO_NAME: Ecoregion name
- SAF_SRM2_NEW: Crosswalk to Society of American Foresters and Society for Range Management cover type 2.
- SAF_SRM2: Crosswalk to Society of American Foresters and Society for Range Management cover type 2.
File: terraclimate_4km_1986_2015_climatevariables.tiff
Description: TerraClimate data for the period 1986-2015, the reference period in our analysis. https://www.climatologylab.org/terraclimate.html
File: ecoregion_nature_conservancy-20250804T211301Z-1-001.zip
Description: A .shp file of western US ecoregions.
File: W_us_TMIN_annual_2C_scaled_proj_1986_2015.tiff
Description: Mean minimum monthly temperature (deg C) for the coldest month under +2 degrees C warming from TerraClimate.
File: W_us_TMAX_annual_2C_scaled_proj_1986_2015.tiff
Description: Mean maximum monthly temperature (deg C) for the warmest month under +2 degrees C warming from TerraClimate.
File: W_us_CWD_annual_2C_scaled_proj_1986_2015.tiff
Description: Mean annual climatic water deficit (mm) under +2 degrees C warming from TerraClimate.
File: W_us_TMIN_annual_1986_2015.tiff
Description: Mean minimum monthly temperature (deg C) for the coldest month from 1986-2015 from TerraClimate.
File: W_us_AET_annual_2C_scaled_proj_1986_2015.tiff
Description: Mean annual actual evapotranspiration (mm) under +2 degrees C warming from TerraClimate.
File: W_us_CWD_annual_1986_2015.tiff
Description: Mean annual climatic water deficit (mm) from 1986-2015 from TerraClimate.
File: W_us_TMAX_annual_1986_2015.tiff
Description: Mean maximum monthly temperature (deg C) for the warmest month from 1986-2015 from TerraClimate.
File: W_us_AET_annual_1986_2015.tiff
Description: Mean annual actual evapotranspiration (mm) from 1986-2015 from TerraClimate.
File: Conif_HUC12_shapefile-20250804T211205Z-1-001.zip
Description: A .shp file of western US HUC12 watersheds.
File: Part2-plotting_script.R
Description: R script for generating the figures in the manuscript
File: Part1-climate_analog_post_processing.R
Description: R script for running the climate analog procedure
Code/software
The code is for R. We used R version 4.3.3 for the analysis and plotting.
