Associated Forest Cover
Common associates of pinyon over most of its range are oneseed juniper (Juniperus monosperma) and Utah juniper (J. osteosperma); redberry juniper (J. erythrocarpa), also a one-seeded juniper, is confined to the southern portion. Alligator juniper (J. deppeana) and Rocky Mountain juniper (J. scopulorum) are also found in some localities (1,4,67). Oneseed juniper predominates in east-central Arizona and most of New Mexico, and extends into western Texas and south-central Colorado. Rocky Mountain juniper is also a common component in northern New Mexico and the western half of Colorado, but it is found over most of the woodlands as well. It usually grows at higher elevations and is seldom dominant in the stand. Utah juniper is the codominant associate in Utah, northern Arizona, western Colorado, and northwestern New Mexico. At higher, more mesic elevations in southern and western New Mexico and westward into central Arizona, alligator juniper commonly forms a component of stands.
Although pinyon-juniper woodlands consist of relatively few tree species, stands exhibit considerable diversity in appearance and composition (4). Some have nearly closed canopies of a single tree species with little or no understory vegetation. Others are open, with widely scattered pines, junipers, or both among grasses and shrubs. A typical pinyon-juniper woodland, with its many-branched trees resembling shrubs, has the appearance of a stunted coniferous forest.
Any particular stand usually contains only a few different plant species, but because of the wide distribution of the type, the total flora associated with woodlands is quite varied (4,67,73). Common tree and shrub associates include: Gambel oak (Quercus gambelii), gray oak (Q. grisea), shrub live oak (Q. turbinella), true mountain-mahogany (Cercocarpus montanus), curlleaf mountain-mahogany (C. ledifolius), antelope bitterbrush (Purshia tridentata), big sagebrush (Artemisia tridentata), black sagebrush (A. nova), serviceberry (Amelanchier spp.), rabbitbrush (Chrysothamnus spp.), Mexican cliffrose (Cowania mexicana), Apache-plume (Fallugia paradoxa), skunkbush (Rhus trilobata), Mormon-tea (Ephedra spp.), yucca (Yucca spp.), opuntia (Opuntia spp.), broom snakeweed (Gutierrezia sarothrae), and buckwheat (Eriogonum spp.).
Some of the more important herbaceous plants are goosefoot (Chenopodium graveolens), rock goldenrod (Solidago pumila), gilia (Gilia spp.), penstemon (Penstemon spp.), segolily (Calochortus nuttallii), globemallow (Sphaeralcea spp.), white aster (Aster hirtifolius), hymenopappus (Hymenopappus filifolius var. lugens), Indian ricegrass (Oryzopsis hymenoides), dropseed (Sporobolus spp.), needle-and-thread (Stipa comata), squirreltail (Sitanion hystrix), Junegrass (Koeleria pyramidata), galleta (Hilaria jamesii), blue grama (Bouteloua gracilis), sideoats grama (B. curtipendula), ring muhly (Muhlenbergia torreyi), western wheatgrass (Agropyron smithii), bluebunch wheatgrass (A. spicatum), slender wheatgrass (A. trachycaulum), downy chess (Bromus tectorum), and threeawn (Arisitada spp.).
- 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. http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm
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