Terrestrial Condition Assessment (TCA) Grassland Encroachment

Direct Download (Raster Data Gateway)
Objective: An indicator that identifies where tree density has exceeded the levels presumed to be present in pre-Euro-American settlement non-forest vegetation. By our definition, non-forest areas cannot exceed 25% tree canopy cover. Fire exclusion, climate, and human activities affect the progression of trees into non-forested ecosystems. Encroached areas may require restoration to meet ecological objectives. Restoration practices will be ecosystem specific.
Data: The indicator uses areas identified as grasslands using LANDFIRE’s Biophysical Settings (BpS) raster dataset (US_140BPS_20180618) along with a cross-walk based on Reeves MC, Mitchell JE (2011) (https://research.fs.usda.gov/treesearch/41872) to identify BpS units that were likely to be grasslands during pre-European times. Presence of conifer tree species was developed using USGS National Landcover Database (NLCD) legend class “42 – Evergreen Forest”. The Evergreen Forest class represents “areas dominated by trees generally greater than 5 meters tall, and greater than 20% of total vegetation cover. More than 75% of the tree species maintain their leaves all year. Canopy is never without green foliage.” Grassland conifer encroachment is identified where raster pixels are identified as both “grasslands” and NLCD “Evergreen Forest”. In years when NLCD is not updated, data is reused from the previous year, which is why there is only data for 3 of the 5 assessment years from 2020-2024. NLCD versions used: NLCD 2011 (TCA Assessment 2020), NLCD 2019 (TCA Assessment 2022), NLCD 2021 (TCA Assessment 2023). Encroachment for the 2023 TCA Assessment is 1-bit and therefore only contains values of 1 indicating where encroachment was observed, rather than the binary data from other years.
Format: Raster data are binary: (1) likely encroached or (0) not encroached
Resolution: 250m
Source: Custom grassland-BpS crosswalk, NLCD conifer presence
Additional Resources:
Details on Method Changes and Source Data Versions
Overview of the Terrestrial Condition Assessment: TCA Hubsite or Landfire Office Hour Presentation
Explore the results of the most recent assessment: TCA Interactive Data Viewer
Learn more about the TCA KPI: TCA Dashboard
*if you have trouble viewing the Dashboard, please submit a Tableau Viewer Access Request

This record was taken from the USDA Enterprise Data Inventory that feeds into the https://data.gov catalog. Data for this record includes the following resources: ISO-19139 metadata ArcGIS Hub Dataset ArcGIS GeoService For complete information, please visit https://data.gov.