Pinyon–juniper woodland

Pinyon–juniper woodland, also spelled piñon–juniper woodland, is a biome found mid-elevations in arid regions of the Western United States, characterized by being an open forest dominated by low, bushy, evergreen junipers, pinyon pines, and their associates. At lower elevations, junipers often predominate and trees are spaced widely, bordering on and mingling with grassland or shrubland, but as elevation increases, pinyon pines become common and trees grow closer, forming denser canopies. Historically, pinyon-juniper woodland has provided a vital source of fuel and food (particularly piñon nuts) for peoples of the American Southwest.

Both pinyon pine and juniper species reproduce exclusively through seed production, and produce most of their seeds during mast years, which occur about every three to five years. Birds and small mammals in the ecosystem are the main distribution method for these seeds, and the woodlands support a number of native species like the Pinyon mouse and the Pinyon jay. These animals often at least partially subsist on their seeds, spreading them by caching them in underground holes.