Pinyon-juniper woodlands have always been part of the fabric of western landscapes. However, human land use, reduced fire occurrence, and climatic conditions have contributed to widespread changes. Historically, woodlands were restricted primarily to areas where grassy fuels were limited. Periodic fire, and occasionally severe drought, killed trees and maintained a balance of grasslands, shrublands, and woodlands. Altered fire regimes have allowed more trees to establish, grow, and spread by seeds that are dispersed by birds and small mammals.

This website provides a science-based resource to help people better understand the science and management around woodland encroachment in sagebrush ecosystems. Sagebrush ecosystems across the West are struggling to thrive amidst numerous threats, and these ecosystems are critical for biodiversity, wildlife habitat, rural livelihoods, economies, and traditional uses. Alongside invasive annual grasses and land use conversion, tree expansion or encroachment into historic shrublands is among the primary threats to the sagebrush biome.

This PJ Encroachment Education Project is an interagency effort that is led by University of Nevada, Reno Extension. This project is supported by the USDA Natural Resources Conservation Service’s Working Lands for Wildlife partnership, the Bureau of Land Management and the Intermountain West Joint Venture’s Partnering to Conserve Sagebrush Rangelands partnership.