Pinyon trees are the dominant overstory species on more than 36 million acres of land in the southwestern United States. These short, twisted trees with large branching crowns live in association with more than 1000 species of microbes, plants, insects, birds, and mammals.
America has two species of common native pinyon trees, Pinus edulis, which is also known as Colorado pinyon, and Pinus monophylla, known as singleleaf pinyon.
Often local people in New Mexico and Colorado call nuts from the Pinus monophylla tree "pine nuts" as a way of distinguishing the two species. In the pinyon nut industry, Colorado pinyon is often called hard shell while the singleleaf pinyon is known as soft shell.
In Colorado, pinyon trees grow along the western border on dry lowlands, slopes and mesas; on the western side of the Sangre de Cristos, in the Great Sand Dunes National Monument, in the eastern foothills and plains south of Colorado Springs, in the Arkansas River valley to the Buena Vista area, on the Palmer divide between Colorado Springs and Castle Rock, along the foothills up to Golden, and east of Trinidad.
Colorado pinyon typically grows in areas where precipitation ranges between 10 to 15 inches, which in the recent past has typically occurred at elevations between 5200 feet and 9000 feet. It is most abundant at elevations between 7000 to 7900 feet. Local environmental conditions, such as soil moisture and temperature, greatly affect the elevations at which Colorado pinyon can grow. Colorado pinyon often grows in association with Utah juniper.
Singleleaf pinyon is found primarily in Nevada, western Utah, and parts of northern Arizona. It is a drought- and cold-tolerant species that grows in areas where the average precipitation is between 8 to 18 inches and elevations are between 3200 to 9200 feet. Like Colorado pinyon, the single-leaf pinyon generally grows in association with Utah juniper.