As a codominant with juniper species (Juniperus
spp.), pinyon trees predominate in pinyon-juniper woodlands of the semidesert zone, which cover nearly 24.7 million ha (61 million acres), extending from Texas to California (9). Woodlands in which pinyon is the major pine species cover about 14.9 million ha (36.9 million acres) in Arizona, Colorado, New Mexico, and Utah. Outliers in California, Oklahoma, Texas, and Wyoming contribute a relatively insignificant acreage to the total (48). However, the outlier in California has been considered a population of 2-needled individuals of single-leaf pinyon (Pinus monophylla),
and more recently, a new species, California single-needle pinyon (Pinus californiarum)
(5,44). - The native range of pinyon.
Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods. Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965). U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp.