Managing Arid and Semi-Arid Watersheds

Mixed Conifer Forests

Picture of mixed conifer forest vegetation
Map of mixed conifer forests in Arizona
Map of mixed conifer forests in Arizona
(Click image to see image large enough to read text)

General Information

Tree Species—This forest type is found at elevations between 8,000 and 10,000 ft. Seven coniferous and one deciduous tree species in a variety of mixtures characterize these high elevation forests. These species include Engelmann spruce (Picea engelmannii), blue spruce (P. pungens), Douglas-fir (Pseudotsuga menziesii var. glauca), white fir (Abies concolor), corkbark fir (A. lasiocarpa var. arizonica), ponderosa pine (Pinus ponderosa), southwestern white pine (P. strobiformis), and quaking aspen (Populus tremulodies).

Mixed conifer type in White Mountains of Arizona
Mixed conifer type in White Mountains of Arizona

Precipitation—Annual precipitation in high elevation mixed conifer forests (above 9,500 ft) ranges from 30 to 45 inches and is usually in excess of potential evapotranspiration (figure 2). As a result, streams originating in this area are often perennial. Streams originating in low elevation mixed conifer forests (8,000 to 9,500 ft) are mostly intermittent. Snowmelt runoff is a significant source of annual runoff. Also see: water yield and potential increase.

The relatively high precipitation amounts in the mixed conifter forest type results in a relatively lush vegetative environment in contrast to the vegetation types found at the lower elevation levels. This fact also contributes to its low potential for erosion and subsequent sedimentation.

Resources and activities—Mixed conifer forests contain: water, timber, forage, recreation opportunities (camping, hunting, picnicing, hiking, and site-seeing), and habitats for a variety of big and small game animals, rodents, and game and non-game birds. Relatively little herbaceous vegetation is produced under dense overstories in these forests. As a consequence, carrying capacities for livestock and wildlife, which graze these forests in summer, are low in relation to other vegetative types in the region.

Mixed conifer type
Mixed conifer type

Soils—Soils, which vary in origin, are medium to moderately fine textured. Soil materials (regolith) are usually deep, allowing deep water penetration and storage. Mixed conifer forests are found over a range of slope and aspect combinations, although slope steepness is generally greater than in other vegetative types.

Images Available

There are currently about 170 images available in the image database illustrating various aspects and conditions found in mixed conifer ecosystems in the southwestern United States. These can be accessed after getting into the data base by using the key word mixed conifer. Additional keywords are available for searching the images in a drop down list within the database.