Woodland Expansion

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

New Science Guide Details Better Approach for Addressing Woody Encroachment Across America’s Grasslands

Reducing Woody Encroachment in
Grasslands A new guide, 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.

Read the full guide here.

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. For more information on how to apply this strategy, view this technical video:

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.

  1. 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. More details on this product available here. Map of
categorical tree cover.

  2. 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. More details on this product available here. Map of woody transitions.

  3. RAP 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.More details on this product available here. Map of annual

  4. RAP Biomass. 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. More details on this product available here. Map of annual biomass.