Environmental Description:  These upper montane or subalpine forests occur in many of the mountainous areas of the Colorado Plateau, Arizona - New Mexico Mountains and southern Rocky Mountains, where they are often the matrix forests of the subalpine zone. They occur above the warmer and drier montane forests of the West, which are typically mixed-coniferous forests. Average temperatures are fairly uniform across the alliance''s range, with mean July and January temperatures of 12° and -10°C, respectively (Burns and Honkala 1990a). Snowpacks can be deep, but often melt quickly, and summers are cool. Summer frosts are characteristic, especially on sites where cold air pools. Elevations range from 2600-3500 m. Sites include gentle to very steep mountain slopes, ridgetops, and plateaus. In some locations where there is cold-air drainage, these forests may extend down in elevation into the montane zone, where they will occupy dry stream terraces, toeslopes, with cooler temperature regimes such as northern aspects. Parent materials and soils are variable across the distribution of the alliance. Parent materials include ash, tuff, lava, basalt, granitics, quartzite, dolomite, rhyolite, and other sedimentary rock types. Stands can also occur on colluvium or alluvium. Soils are typically not deep, poorly developed, and can have significant amounts of rock and gravel in the profile. Subalpine soils, such as those found associated with these forests, often show evidence of podzolization processes, especially in the north, and poorly decomposed organic layers are common.