Rocky Mountain Pinyon - Juniper Woodland
Southern Rocky Mountain Two-needle Pinyon - One-seed Juniper Woodland
SWAP General Vegetation Type
ALPINE and MONTANE VEGETATION
The Rocky Mountain Piñon-Juniper Woodland [M027] occurs at 1,980-2,600 m (6,500-8,500 ft) as a savanna to woodland in dry mountains and foothills of the Southern Rocky Mountains, Arizona/New Mexico Mountains, Colorado Plateaus, and High Plains and Tablelands ecoregions, and isolated locations of the Chihuahuan Desert ecoregion. It is characterized by shorter (3-20 m tall) conifer trees that include oneseed juniper (Juniperus monosperma) and/or two-needle piñon. Rocky Mountain juniper (J. scopulorum) may replace oneseed juniper at higher elevations. Savannas have widely spaced, mature trees with lush perennial grasses and scattered shrubs. Woodlands are typically open-canopied (10-30% cover), but closed-canopy stands with a sparse understory are not uncommon. Understory shrub species may include Bigelow sage (Artemisia bigelovii), alderleaf mountain mahogany (Cercocarpus montanus), rubber rabbitbrush (Ericameria nauseosa), wavyleaf oak (Quercus pauciloba), and skunkbush sumac (Rhus trilobata). Succulents include tree cholla (Cylindropuntia imbricata), tulip pricklypear (Opuntia phaeacantha), and plains pricklypear (O. polyacantha). The herbaceous layer varies from sparse to grassy. Representative grass dominants are Scribner’s needlegrass (Achnatherum scribneri), sideoats grama (Bouteloua curtipendula), blue grama (B. gracilis), needle and thread (Hesperostipa comata), and James’ galleta (Pleuraphis jamesii). Forbs may be diverse but generally have low abundance; representative species include wholeleaf Indian paintbrush (Castilleja integra), James’ buckwheat (Eriogonum jamesii), fineleaf hymenopappus (Hymenopappus filifolius), and many-flowered ipomopsis (Ipomopsis multiflora). Substrates range from deep loams to shallow, skeletal soils on rocky sites. Fire regimes vary from stand-replacing, high severity but infrequent fires (or no fires) to low severity, surface fires of savannas.