Keeping Trees Out of Grasslands

When woody plants move into grasslands, a host of negative consequences results. Defending intact grassland cores from encroachment is the most effective strategy for saving our precious grasslands.

Woodland expansion into grasslands displaces rangeland wildlife and reduces productivity and profitability of grazing lands. WLFW’s Framework seeks to halt woody expansion to maintain intact grasslands through preventative woody plant management actions and targeted restoration tactics within priority landscapes.

Strategic Approach

WLFW’s approach for tackling this threat relies on statewide maps identifying large, intact grasslands with relatively low, or no, woodland expansion. Intact grasslands serve as anchor points for conservation action and inform a proactive strategy for management: Defend the Core, Grow the Core, Mitigate Impacts.

Resources for Download

Science-backed approach

"Reducing Woody Encroachment in Grasslands: A Guide to Risk and Vulnerability", produced through a partnership between public university extension programs in the Great Plains, the USDA-NRCS’s Working Lands for Wildlife (WLFW), the USDA-NRCS’s Central National Technology Support Center (CNTSC), and various other conservation partners, provides the first-ever framework for addressing woody encroachment, now recognized as one of the top two drivers of grassland loss in the Great Plains.

The 'Vulnerability Guide' was followed by the "Reducing Woody Encroachment in Grasslands: A Pocket Guide for Planning and Design" which details conservation planning guidelines for reducing woody encroachment in grasslands. It was co-produced by the Great Plains Extension Partnership and WLFW.

Great Plains Grassland Initiatives

These state-based initiatives provide technical and financial resources to eligible ranchers to reduce the vulnerability of core grasslands from woody encroachment.



Yield Gap

WLFW researchers calculated the economic toll of woodland expansion on a county-wide basis across the Great Plains.


RFD-TV Features GPGI

NCBA's Cattlemen to Cattlemen featured the NRCS Great Plains Grasslands Initiatives. The full episode aired nationally on Nov. 29, 2022, with additional segments airing in 2023.


Spatial Data

The maps below enable practitioners to rapidly visualize and analyze opportunities for threat reduction. Local maps and data should also be incorporated, where available, to refine conservation delivery. Multiple spatial data types should be used in combination to meet WLFW’s strategic approach.

Categorical Tree Cover

This map depicts categorical tree cover classes across the Great Plains biome, annually 1984-present. Class categorization was performed with the RAP vegetation cover product at 480m resolution which mirrors the size of many projects in the region and corresponds with thresholds of known declines in prairie chicken populations. Data represents tree canopy cover in the following classes: 0-4% and >=5%. It can be used for identification of relatively treeless core areas for proactive management and to monitor effectiveness through time.

Woody Transitions

This map depicts vegetation transitions to trees in the Great Plains biome at two scales: broad and moderate (visualization changes upon zooming). It can be used as an early warning for the loss of resilience to woody expansion within intact but vulnerable grassland cores. The data provides opportunities to adapt management strategies and actions before intact grasslands become compromised and require more expensive rehabilitation. Transition maps, when combined with expert knowledge and other field inventory/remote sensing products, enable more proactive management to get ahead of large-scale vegetation change.

Vegetation Cover

These maps provide annual percent cover estimates from 1984 to present of: annual forbs and grasses, perennial forbs and grasses, shrubs, trees, and bare ground. The data can be used to assess biotic conditions to inform management actions and monitor vegetation through time. Tree maps provide a continuous cover estimate to support site inventory and monitoring before and after management.

Vegetation Production

These maps provide annual and 16-day aboveground biomass from 1986 to present of: annual forbs and grasses, perennial forbs and grasses, and herbaceous (combination of annual and perennial forbs and grasses). Estimates represent accumulated new biomass throughout the year or 16-day period and do not include biomass accumulation in previous years. The data can be used to monitor herbaceous biomass change over time, assess herbaceous biomass (forage) loss to woodland expansion, and its recovery following woody plant removal.

Landowner led. Science informed.
Agency supported.