Detailed Soil Map Units
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10—Castlecrest-Sunnotch complex, 5 to 45 percent slopes
Map Unit Setting
General location: Southern and western side slopes of Mount Mazama
Major land resource area (MLRA): 3
Elevation: 6,000 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 30 days
Map Unit Composition
Castlecrest and similar soils:
45 percent
Sunnotch and similar soils: 40 percent
Minor components: 15 percent
Characteristics of the Castlecrest and Similar Soils
Setting
Landform: Ashflow
Geomorphic position: Mountainsides
Parent material: Ash and pumice
Properties and qualities
Slope: 5 to 45 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—(003XY706OR) Tsuga mertensiana/Luzula glabrata var. hitchcockii
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 Sunnotch and Similar Soils
Setting
Landform: Debris flow
Geomorphic position: Side slopes of Mount Mazama
Parent material: Cinders and ash
Properties and qualities
Slope: 5 to 45 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 6.6 inches
Interpretive groups
Ecological site: Forestland—(003XY706OR) Tsuga mertensiana/Luzula glabrata var. hitchcockii
Typical profile
Oi—0 to 1 inch; slightly decomposed plant material
A1—1 inch to 3 inches; gravelly ashy sandy loam
A2—3 to 11 inches; ashy loamy sand
Bw—11 to 25 inches; very gravelly ashy loamy sand
2C—25 to 61 inches; very gravelly ashy sand
Characteristics of the Minor Components
Llaorock soils
Percentage of map unit: 10 percent
Landform: Stratovolcano
Geomorphic position: Ash mixed with residuum and colluvium derived from andesite on side slopes of Mount Mazama
Rock outcrop
Percentage of map unit: 5 percent
Landform: Stratovolcano
Geomorphic position: Lava flows on side slopes of Mount Mazama
Major Soil Features and Properties Affecting Management
Castlecrest soil
• Sandy textures
• Low soil strength
• Dustiness if vegetation is removed
• Water erosion
Sunnotch soil
• Rock fragments in soil profile
• Water erosion
