23 10—Castlecrest-Sunnotch complex, 5 to 45 percent slopes

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

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