Pinyon and juniper expansion areas and persistent woodlands in the Snake River Plain, Northern Basin and Range, and Central Basin and Range level III ecoregions in the western United States

This data publication contains raster spatial data (GeoTIFF) representing areas of pinyon-juniper (PJ) expansion into sagebrush ecosystems and persistent woodland and expansion within the Great Basin region of the western United States, which includes portions of Nevada, Idaho, Oregon, and Utah. To determine areas for potential fuel treatments, we overlayed PJ cover onto the dominant sagebrush associations. We used the Rangeland Analysis Platform to identify three phases (I, II, and III) or successional stages of PJ expansion based on the amount of tree cover expected for the different sagebrush associations. Because fuel treatments are conducted primarily in the early phases (Phase I and II successional stages) of tree expansion, it is important to designate these phases on the landscape. To characterize the persistent woodlands, we identified the LANDFIRE Biophysical Settings (BPS) categories that represented persistent pinyon and juniper (PJ; Pinus monophylla, Juniperus occidentalis and/or J. osteosperma) woodlands within the dominant sagebrush associations. These areas are considered high value resources and are excluded from fuel treatments. The data for PJ expansion areas and persistent woodlands represent conditions from 2016-2022.
In sagebrush ecosystems the responses to woody fuel treatments are highly dependent on the dominant sagebrush association, the presence of pinyon-juniper expansion, and as their resilience to wildfire and fuel treatments (resilience) and resistance to invasive annual grasses (resistance). New ecologically relevant and climate sensitive indicators of resilience and resistance based on climate and water availability have been developed recently. However, information is also needed on the locations and extents of the dominant sagebrush associations, the different phases (successional stages) of pinyon-juniper (PJ) expansion into the shrublands, if any, and the extent of persistent pinyon-juniper (PJ) woodlands. This data layer provides the locations and extents of PJ expansion areas and persistent PJ woodlands within the dominant sagebrush associations.
For more information about these data and this study, see Chambers et al. (2023; https://doi.org/10.1186/s42408-023-00230-2).