331Aa Camas/Weippe Basalt Plateaus

Landscape Characteristics:

Weakly dissected basalt plateaus that are overlain by extensive areas of loess and volcanic ash. Elevations range from 800 to 4500 feet. Drainage density is moderate and wetlands are fairly common.

Climate:

Mean annual precipitation ranges from 15 to 45 inches, about 40 to 50 percent falling as snow. The soil temperature and moisture regimes are frigid and typic xeric.

Potential Vegetation:

Fescue-wheatgrass with Western ponderosa forest at higher elevations and on north aspects.

Relationships of Dominant Map Unit Components:

Landform Geology Soil Taxa
Plateaus Loess underlain by basalt Argixerolls/Argialbolls/Udivitriands/Fragiborolls

Disturbance and Land Use:

The primary natural disturbance is fire. Land use is predominantly hayland, grazing, and timber harvest.