Soil Survey of Crater Lake National Park, Oregon
General Soil Map Units
Soils That Are in Valleys and Formed in Ash and Pumice Flow Deposits of Ash, Pumice, and Cinders
Number of map units: 4
Percentage of park: 42 percent
6. Unionpeak-Castlecrest (mountain hemlock)
Percentage of park: 7 percent
Location in park: Along the northern, eastern, and southern flanks of the caldera rim
Drainage class: Somewhat excessively drained
Slope range: 0 to 35 percent
Elevation: 5,000 to 7,000 feet
Average annual precipitation: 50 to 70 inches
Average annual air temperature: 38 to 42 degrees F
Frost-free period: 0 to 50 days
Minor components: 10 percent Sunnotch soils and 5 percent Rock outcrop
Present vegetation: Mountain hemlock and lodgepole pine
Unionpeak soils
Depth class: Moderately deep to a duripan
Permeability: Rapid throughout the solum and moderately rapid in the weakly cemented duripan
Position on landscape: Ashflows
Parent material: Pumice, ash, andesite, and dacite
Surface texture: Ashy sandy loam
Subsoil texture: Gravelly ashy loamy sand
Castlecrest soils
Depth class: Very deep
Permeability: Rapid
Position on landscape: Mountain flanks and mountainsides
Parent material: Pumice and ash
Surface and subsoil texture: Paragravelly ashy loamy sand
Substratum texture: Ashy coarse sand and ashy sand
