Soil Survey of Crater Lake National Park, Oregon
General Soil Map Units
Soils That Are on Uplands and Formed in Airfall-Deposited Ash and Pumice
Number of map units: 3
Percentage of park: 29 percent
2. Timbercrater-Llaorock-Castlecrest (mountain hemlock)
Percentage of park: 17 percent
Location in park: Primarily north and east of Mount Mazama, downwind of the eruption
Depth class: Very deep
Position on landscape: Ridges, mountain flanks, and mountainsides
Slope range: 2 to 80 percent
Elevation: 5,500 to 8,900 feet
Average annual precipitation: 50 to 80 inches
Average annual air temperature: 38 to 42 degrees F
Frost-free period: 0 to 50 days
Minor components: 7 percent Rubble land, 3 percent Unionpeak soils, and 5 percent Rock outcrop
Present vegetation: Mountain hemlock, whitebark pine, and lodgepole pine
Timbercrater soils
Drainage class: Excessively drained
Permeability: Very rapid
Parent material: Airfall deposits of pumice and ash
Surface texture: Paragravelly ashy loamy sand
Subsoil texture: Very paragravelly ashy loamy sand
Substratum texture: Extremely paragravelly ashy sand
Llaorock soils
Drainage class: Somewhat excessively drained
Permeability: Rapid
Parent material: Residuum and colluvium derived from andesite mixed with ash
Surface texture: Gravelly ashy sandy loam
Subsoil texture: Extremely stony medial sandy loam
Castlecrest soils
Drainage class: Somewhat excessively drained
Permeability: Rapid
Parent material: Airfall deposits of pumice and ash
Surface texture: Paragravelly ashy loamy sand
Subsoil texture: Paragravelly ashy loamy sand
Substratum texture: Ashy coarse sand
