Physiognomy and Structure: Vegetation included in this alliance has an open to moderately dense tree canopy that is typically 2-5 m tall. Stands are solely dominated by evergreen scale-leaved trees. Scattered evergreen needle-leaved or deciduous broad-leaved trees may be present, but they never codominate. A sparse to moderately dense shrub layer may be present as a mixture of broadleaf and microphyllous, deciduous or evergreen shrubs that are usually less than 2 m tall. A sparse to moderately dense herbaceous layer dominated by perennial graminoids is usually present. Perennial forbs may be scattered. Annual forbs and grasses may be seasonally present.

Floristics: This woodland alliance occurs in foothill and lower montane zones in the Rocky Mountains from southern Alberta and northern Montana south to central Colorado and on escarpments across Wyoming extending out into the western Great Plains. The vegetation is characterized by an open to closed tree canopy (typically 10-35% cover) or patchy woodland usually 2-8 m tall that is dominated by either Juniperus scopulorum or, less commonly, Juniperus osteosperma. Pinus flexilis is absent or has low cover. In the plains stands the deciduous broad-leaved tree Fraxinus pennsylvanica may be present. Higher elevations stands may have scattered individuals of Pinus ponderosa, or Pseudotsuga menziesii may be present with low cover (<5% cover). Although cover of trees is typically >10% in this alliance, stands with 5-9% tree cover are included when trees characterize the stand and cover of trees exceeds cover of understory layers. The understory is characterized by open to moderately dense short-shrub cover (usually 10-35%) but includes denser stands. The dominant shrub species are Artemisia nova, Artemisia tridentata, Cercocarpus ledifolius, Cercocarpus montanus, Prunus virginiana, and Purshia tridentata. Common, but less abundant shrubs include Ericameria nauseosa (= Chrysothamnus nauseosus), Physocarpus monogynus, Purshia tridentata, Rhus trilobata, Ribes spp., Rubus deliciosus, and Symphoricarpos spp. Scattered dwarf-shrubs such as Artemisia frigida or Linanthus pungens (= Leptodactylon pungens) are frequently present. Total shrub cover is typically >10%, but if less, then shrub cover exceeds herbaceous layer. The herbaceous layer is dominated by graminoids typical of dry habitats. These species include Achnatherum hymenoides (= Oryzopsis hymenoides), Bouteloua gracilis, Carex rossii, Festuca idahoensis, Leucopoa kingii (= Festuca kingii), Hesperostipa comata (= Stipa comata), Leymus ambiguus, Muhlenbergia montana, Piptatheropsis micrantha (= Oryzopsis micrantha), Poa secunda, Pseudoroegneria spicata, and Schizachyrium scoparium. Perennial forbs are sparse but may be fairly diverse. The most common forbs are Achillea millefolium, Artemisia ludoviciana, Campanula rotundifolia, Eriogonum umbellatum, Galium boreale, Helianthus pumilus, Heterotheca villosa, Heuchera bracteata, Maianthemum stellatum, Penstemon virens, Potentilla fissa, and Senecio integerrimus. The fern Cystopteris fragilis and the cactus Opuntia polyacantha are often present. In some stands mosses and lichens cover up to 72% of the ground surface. Annual grasses and forbs are seasonally present. Some stands in rocky terrain may lack an understory.

Dynamics:  Woodlands in this alliance are considered to be edaphic or topographic climax communities (Hansen et al. 1984, Tiedemann et al. 1987). Juniperus scopulorum is a long-lived species. Hansen and Hoffman (1988) found most trees in stands they sampled to be over 120 years, with some individuals older than 360 years. Fire can be used to control Juniperus scopulorum stands on rangeland because the species will not resprout after being burned (Wright et al. 1979, Fischer and Bradley 1987). Young individuals are most vulnerable to fire (Wright et al. 1979, Fischer and Bradley 1987). The effect of fire on a stand is largely dependent on the tree height and density, fine fuel load on the ground, weather conditions, and season (Wright et al. 1979). Trees are more vulnerable in open stands where fires frequently occur in the spring when the humidity is low, wind speeds are over 10-20 mph, and there is adequate fine fuels to carry fire (Wright et al. 1979, Fischer and Bradley 1987). Under other conditions, burns tend to be spotty with low tree mortality. Large trees are generally not killed unless fine fuels, such as tumbleweeds, have accumulated beneath the tree to provide fuel ladders for the fire to reach the crown. Closed-canopy stands rarely burn because they typically do not have enough understory or wind to carry a fire. Altered fire regimes, cutting trees for fencing, and improper grazing by livestock have significant impacts on the quality of sites. Grazing by livestock can modify the fire regime by removing the fine fuels that carry fire. Fire, livestock grazing, and trampling by hikers and vehicles disturb biological soil crusts that help maintain soil structure, reduce soil erosion, provide habitat for plants and preserve biological diversity. More study is needed to understand and manage these woodlands.