Colorado Statewide Forest Resource Assessment

Mixed Conifer 14The mixed conifer forest type occurs at approximately 6,900 to 10,500 feetin elevation, nestled between lower-elevation forests such as ponderosapine and higher-elevation subalpine forests such as spruce-fi r. Colorado has1.8 million acres of mixed-conifer forest, which is primarily managed by theUSFS (873,280 acres) and private landowners (602,356 acres). As its namesuggests, the mixed-conifer type includes a diverse range of species. Thedistribution and structure of mixed-conifer forests are strongly infl uenced bytemperature and moisture gradients, in addition to soil types and fi re. White fi roften dominates as the climax species on moist sites and in the southern partof the state, while ponderosa pine, Douglas-fi r or Rocky Mountain juniper tendto be the climax species on warmer and drier sites. Engelmann spruce, bluespruce, subalpine fi r, bristlecone pine and limber pine also may be present inthe mix.Fire regimes in mixed-conifer forests vary by site, but generally are of lowfrequency and mixed severity, ranging from 20-year cycles to 150 years ormore depending on moisture and elevation. 15 As a result of fi re suppression,many mixed-conifer forests currently are denser and contain more deadfuel than they did historically. These heavy accumulations greatly increasethe chances for high-intensity, stand-replacing crown fi res. Prior to humansettlement, these stand-replacing fi res would only occur every 200 to 500years. Mixed-conifer forests are important for watershed protection andrecreational and scenic opportunities. Mixed-conifer forests provide manywood products manufactured by local Colorado businesses. Compared toother forest types, the value of mixed-conifer forests for wildlife is not wellunderstood. However, many neotropical migratory songbirds breed in mixedconiferforests and elk use them extensively during calving season and insummer. Flammulated owls and northern goshawks are among the sensitivespecies that use mixed-conifer stands, especially those that include bluespruce. Twenty Species of Greatest Conservation Need use mixed-coniferforests as a primary habitat (CDOW 2006).Ponderosa PinePonderosa pine forests, woodlands and savannas occupy approximately 2million acres in Colorado or 8 percent of the state’s forested land. Althoughponderosa pine is most common between 6,000 and 9,000 feet, it begins toappear on the landscape around 5,000 feet where prairies and shrublandstransition into open ponderosa pine forests. 16 Private landowners control 49percent of this forest type, while the USFS manages 34 percent. Becauseit is more accessible than other species, and largely in private ownership,ponderosa pine has been an important source of lumber and other woodproducts throughout Colorado’s history. These forests currently are asignifi cant resource for recreation and water supply. They also are thebackdrop for the majority of the state’s wildland-urban interface communities.14This section is adapted from information available from LANDFIRE (www.landfire.gov) and NatureServe (www.natureserve.org/explorer).15For more specific information about this variation in fire regimes, please see the LANDFIRE biophysical settingdescriptions for mixed-conifer at www.landfire.gov or the USFS fire effects information system at www.fs.fed.us/database/feis/.16For more information on Colorado’s ponderosa pine forests, see the CSFS 2004 Report on the Health of Colorado’sForests at http://csfs.colostate.edu/pages/pub-csfs2.html.10