Rangeland Production Lost to Tree Encroachment
Tree Encroachment
About these Reports
Herbaceous production is central to the function and structure of rangelands and the ecosystem services they provide. Tree encroachment of rangelands significantly reduces herbaceous production as trees out-compete grasses and forbs for limited resources. This lost production has cascading impacts on food and fiber provisioning, habitat quality, water storage, and biodiversity for endemic rangeland species.
These reports build upon recent advances in remote sensing and vegetation modeling to provide state- and county-level estimates for rangeland production lost to tree encroachment. Use the interactive map below to navigate to any of the 17 states and 1,062 counties for which we have data. Learn more about the science and analysis behind these reports in the Supporting Information section, below.
Reports updated November 10, 2023. See the changelog for details.
Westwide Rangeland Production Lost to Tree Encroachment
Rangeland Production Losses Map
Click any state on the map below to access its report.The map depicts rangeland production losses for the year 2022 that resulted from increases in tree cover since 1990. The colors show percent losses relative to production that would have been acheived without increases in tree cover. Counties estimated to have had significant amounts of forest prior to Euro-American settlement are masked in grey to focus attention on historical grasslands and shrublands.
Rangeland Production Losses Plots
The plots below show herbaceous production lost to tree cover
expansion on an annual (left) and cumulative (right) basis for years
1990- 2022. The annual plot displays the same information as the map
above. Rangeland production may increase when tree cover has declined
due to disturbance or management.
Rangeland Production and Tree Cover Summary
| Rangeland production in 2022 | 300,058,705 tons |
| Rangeland production losses in 2022 | 13,562,136 tons (4.32%) |
| Cumulative rangeland production losses since 1990 | 370,441,789 tons |
| Tree cover in 2022 | 42,035,145 acres |
| Tree cover change since 1990 | +13,213,788 acres |
| Tree cover percent in 2022 | 6.2% |
Supporting Information:
Tree encroachment is the most commonly used scientific term internationally to describe the increase of tree plants at the expense of herbaceous plants in grass-dominated ecosystems. We therefore use this term in this report, but we acknowledge the importance of local and regional terminology that may better contextualize this process in rangelands. Around the world, expansion, invasion, infill, encroachment, colonization, state transitions or regime shifts are used to characterize this biological process. Ultimately, this model characterizes rangeland production losses in rangelands due to increases in trees - irrespective of the regional distinctions used to describe the process.
Vegetation productivity is the most fundamental and important metric in rangelands and measuring losses in rangeland production to tree encroachment at multiple scales has been one of the major knowledge gaps in the rangeland discipline. Wildlife, livestock, and many ecosystem services rely on herbaceous production (i.e., the combined production of grasses and forbs) that is being displaced by tree encroachment.
The production loss statistics and figures presented in these reports are derived from the analysis in Tree encroachment threatens the conservation potential and sustainability of U.S. rangelands. In this report, estimates of production losses are directly related to tree cover change based on a 1990 baseline, and changes are not the result of climatic or land use factors (which the analysis accounts for). In short, the values presented in these reports represent the difference between the production that would have been achievable given stable tree cover since 1990 vs. observed production estimated using a satellite-derived dataset. This is referred to as a yield gap, as depicted in the plot below.
- Total area: The total area of the state or county covered by the report.
- Analysis area: The land area used to generate the data found in this report. All land cover classes were included in this analysis except lands labeled as 1) "cultivated" in the National Agricultural Statistics Service (NASS) Cropland Data Layers, 2) "developed" in the 2016 National Land Cover Database (NLCD), and 3) "historically forested" in the LANDFIRE Biophysical Settings (BpS).
- Area excluded from analysis: The land area removed from this analysis. Specifically, this is the total area labeled as 1) cultivated (NASS), 2) developed (NLCD), and 3) historically forested (BpS).
Westwide analysis area summary
Westwide analysis area map
- View tree cover data in the Rangeland Analysis Platform web application.
- Download the data table used to produce this report.
- Read the manuscript that describes the modeling process for these reports.
- Learn new guidance on how to better manage tree encroachment and reduce the risk and vulnerability to rangeland production.
- Learn more about the NRCS Working Lands for Wildlife strategy on Woodland Expansion in the Great Plains and Sagebrush biomes.
2023-11-10: Major model revision to incorporate data from the Rangeland Analysis Platform V3, ensuring reports are up-to-date through 2022. Included in this update is a revised land use mask from NLCD 2021, resulting in a slight reduction of the analyzed acreage due to ongoing agricultural conversion. Consequently, this revision may cause discrepancies in production loss estimates compared to the original reports, affecting data even from years prior to 2020. Please note that the 2022 data is provisional and subject to refinement in future updates."
Report generated on 2023-11-10.