72 59—Timbercrater-Llaorock complex, high elevation, 30 to 80 percent slopes

59—Timbercrater-Llaorock complex, high elevation, 30 to 80 percent slopes

Map Unit Setting

General location: Side slopes of Mount Scott

Major land resource area (MLRA): 3

Elevation: 7,000 to 8,900 feet

Average annual precipitation: 50 to 70 inches

Average annual air temperature: 38 to 42 degrees F

Frost-free period: 0 to 25 days

Map Unit Composition

Timbercrater and similar soils: 55 percent

Llaorock and similar soils: 30 percent

Minor components: 15 percent

Characteristics of the Timbercrater and Similar Soils

Setting

Landform: Stratovolcano

Geomorphic position: Side slopes of Mount Scott

Parent material: Ash and pumice

Properties and qualities

Slope: 30 to 80 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—(003XY700OR) Pinus albicaulis/Luzula-Carex

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 Llaorock and Similar Soils

Setting

Landform: Stratovolcano

Geomorphic position: Side slopes of Mount Scott

Parent material: Ash mixed with residuum and colluvium derived from andesite

Properties and qualities

Slope: 30 to 80 percent

Percentage of surface covered with stones and boulders: 3 percent

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 9 inches

Interpretive groups

Ecological site: Forestland—(003XY700OR) Pinus albicaulis/Luzula-Carex

Typical profile

Oi—0 to 1 inch; slightly decomposed plant material

A—1 inch to 7 inches; gravelly ashy sandy loam

AB—7 to 14 inches; very stony ashy sandy loam

Bw1—14 to 24 inches; extremely stony medial sandy loam

Bw2—24 to 61 inches; extremely stony medial sandy loam

Characteristics of the Minor Components

Rock outcrop

Percentage of map unit: 10 percent

Landform: Stratovolcano

Geomorphic position: Andesitic lava flows on side slopes of Mount Scott

Castlecrest soils

Percentage of map unit: 5 percent

Landform: Stratovolcano

Geomorphic position: Airfall ash deposits on side slopes of Mount Scott

Major Soil Features and Properties Affecting Management

Timbercrater soil

• Steep and unstable slopes

• High pumice content

• Water erosion

• Very rapid permeability

Llaorock soil

• Rock fragments on surface

• Steep and unstable slopes

• Rock fragments in soil profile

• Water erosion

 

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