Soil Survey of Crater Lake National Park, Oregon
Crater Lake Institute online library
Detailed Soil Map Units
54—Timbercrater-Castlecrest complex, dry, 2 to 15 percent slopes
Map Unit Setting
General location: Side slopes of mountains and ridges in the southeastern part of the park
Major land resource area (MLRA): 3
Elevation: 5,000 to 6,500 feet
Average annual precipitation: 40 to 60 inches
Average annual air temperature: 38 to 42 degrees F
Frost-free period: 0 to 50 days
Map Unit Composition
Timbercrater and similar soils:
50 percentCastlecrest and similar soils: 45 percent
Minor components: 5 percent
Characteristics of the Timbercrater and Similar Soils
Setting
Landform: Stratovolcano
Geomorphic position: Side slopes of mountains and buttes
Parent material: Ash and pumice
Properties and qualities
Slope: 2 to 15 percent
Percentage of surface covered with stones and boulders: None
Restrictive features: None within a depth of 60 inches
Drainage class: Excessively drained
Permeability: Very rapid
Flooding: Not present
Water table: Not present
Ponding: Not present
Available water capacity: About 8.1 inches
Interpretive groups
Ecological site: Forestland—(003XY704OR) Abies/Arctostaphylos nevadensis/Carex inops
Typical profile
Oi—0 to 2 inches; slightly decomposed plant material
A—2 to 5 inches; paragravelly ashy loamy sand
Bw—5 to 16 inches; very paragravelly ashy loamy sand
C1—16 to 20 inches; extremely paragravelly ashy sand
C2—20 to 62 inches; extremely paragravelly ashy sand
Characteristics of the Castlecrest and Similar Soils
Setting
Landform: Ashflow
Geomorphic position: Ashfall and ashflow material on mountainsides and in valleys
Parent material: Ash and pumice
Properties and qualities
Slope: 2 to 15 percent
Percentage of surface covered with stones and boulders: None
Restrictive features: None within a depth of 60 inches
Drainage class: Somewhat excessively drained
Permeability: Rapid
Flooding: Not present
Water table: Not present
Ponding: Not present
Available water capacity: About 6.3 inches
Interpretive groups
Ecological site: Forestland—(003XY704OR) Abies/Arctostaphylos nevadensis/Carex inops
Typical profile
Oi—0 to 1 inch; slightly decomposed plant material
A—1 inch to 3 inches; paragravelly ashy loamy sand
Bw—3 to 19 inches; paragravelly ashy loamy sand
C1—19 to 26 inches; ashy sand
C2—26 to 38 inches; ashy coarse sand
C3—38 to 64 inches; ashy coarse sand
Characteristics of the Minor Components
Sunnotch soils
Percentage of map unit: 5 percent
Landform: Debris flow
Geomorphic position: Debris flow deposits on mountainsides and in valleys
Major Soil Features and Properties Affecting Management
Timbercrater soil
• High pumice content
• Very rapid permeability
Castlecrest soil
• Sandy textures
• Low soil strength
• Dustiness if vegetation is removed