68 55—Timbercrater-Castlecrest complex, dry, 15 to 30 percent south slopes

55—Timbercrater-Castlecrest complex, dry, 15 to 30 percent south 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: 55 percent

Castlecrest and similar soils: 40 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: 15 to 30 percent; northeast to northwest aspects

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: 15 to 30 percent; northeast to northwest aspects

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 flows on mountainsides

 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

 

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