M333Db St.Joe/Bitterroot Mountains

Landscape Characteristics:

Faulted mountains formed from quartzite, siltite, and argillite. Intrusions of granite occur near the Idaho batholith as well as borderzone materials. Elevations range from 2200 to 7800 feet. Drainage density is moderate to high.

Climate:

Mean annual precipitation ranges from 25 to 80 inches, about 50 percent falling as snow. The soil temperature and moisture regimes are frigid (cryic at higher elevations) and udic. Rain on snow events occur.

Potential Vegetation:

Cedar-hemlock-pine forest with Douglas-fir forest at higher elevations.

Relationships of Dominant Map Unit Components:

Landform Geology Soil Taxa
Mountainsides Metasedimentary Udivitrands/Cryandepts
Glaciated ridges/slopes/cirquelands Metasedimentary Haplocryands/Fulvicryands
Valley floors/fans/terraces Alluvium Vitrands/Aquands/Aquepts/Boralfs

Disturbance and Land Use:

The primary natural disturbances are fire, insects, disease, and flooding. Land use is predominantly intensive timber harvest and mining.