70 57—Timbercrater-Llaorock complex, 10 to 30 percent north slop

57—Timbercrater-Llaorock complex, 10 to 30 percent north slopes

 Map Unit Setting

 General location: Side slopes of mountains and buttes

Major land resource area (MLRA): 3

Elevation: 5,500 to 6,500 feet

Average annual precipitation: 50 to 70 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

Llaorock and similar soils: 40 percent

Minor components: 5 percent

 Characteristics of the Timbercrater and Similar Soils

 Setting

 Landform: Ashfall

Geomorphic position: Side slopes of mountains and buttes

Parent material: Ash and pumice

 Properties and qualities

 Slope: 10 to 30 percent; northwest to northeast 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—(003XY706OR) Tsuga mertensiana/Luzula glabrata var. hitchcockii

 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 mountains and buttes

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

 Properties and qualities

 Slope: 10 to 30 percent; northwest to northeast aspects

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—(003XY706OR) Tsuga mertensiana/Luzula glabrata var. hitchcockii

 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: 5 percent

Landform: Stratovolcano

Geomorphic position: Andesitic lava flows on side slopes of mountains and buttes

 Major Soil Features and Properties Affecting Management

 Timbercrater soil

 • High pumice content

• Very rapid permeability

 Llaorock soil

 • Rock fragments on surface

• Rock fragments in soil profile

 

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