Physiographic Region 62: Southern Rocky Mountains
Description and Ecology: This forest type is found at elevations of 1700 to 3050 m
(5,600-10,000 ft), where it is transitional between ponderosa pine and spruce-fir forests. At
lower elevations, ponderosa pines are common, with Douglas-fir on north-facing slopes and in
drainages. Mixed conifer gives way to spruce-fir at higher elevations. Aspen stands are an
important component, and so pervasive as to be considered an integral part of the mixed conifer
forest. Other tree species present include blue spruce, white fir, lodgepole pine, limber pine, and
bristlecone pine. The stand- and landscape-level structure of mixed conifer forests is shaped by
fire, blowdown, and insect infestations (western spruce budworm, Douglas-fir bark beetle, and
Douglas-fir tussock moth).
Importance and Conservation Status: No bird species is restricted to this forest type. Species
commonly found in mixed conifer include the Yellow-rumped Warbler, Western Tanager, Dark-eyed Junco, and Evening Grosbeak. Insect outbreaks are a regular feature of this forest type, and
can provide a superabundant food source for insectivorous birds. In southwestern Colorado, the
legacy of decades of forest fire suppression includes invasion by fire-intolerant white fir, which
often forms stands with high densities of small trees.
Priority Species Accounts: Two species are identified as high priority in mixed-conifer habitats
in Physiographic Area 62: Blue Grouse and Williamson's Sapsucker.