47 34—Llaorock-Castlecrest complex, 0 to 15 percent slopes

34—Llaorock-Castlecrest complex, 0 to 15 percent slopes

 Map Unit Setting

 General location: Side slopes of mountains and ridges

Major land resource area (MLRA): 3

Elevation: 4,500 to 7,500 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

 Llaorock and similar soils: 40 percent

Castlecrest and similar soils: 40 percent

Minor components: 20 percent

 Characteristics of the Llaorock and Similar Soils

 Setting

 Landform: Stratovolcano

Geomorphic position: Side slopes of mountains and ridges

Parent material: Ash over residuum and colluvium derived from andesite

 Properties and qualities

 Slope: 0 to 15 percent

Percentage of surface covered with stones and boulders: 16 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 Castlecrest and Similar Soils

 Setting

 Landform: Ashflow

Geomorphic position: Ashfall and ashflow material on mountainsides and ridges

Parent material: Ash and pumice

 Properties and qualities

 Slope: 0 to 15 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 Minor Components

 Grousehill soils

 Percentage of map unit: 10 percent

Landform: Ground moraine

Geomorphic position: Ash over glacial till on mountainsides

 Timbercrater soils

 Percentage of map unit: 5 percent

Landform: Ashfall

Geomorphic position: Pumice and ashfall on mountainsides

 Rock outcrop

 Percentage of map unit: 5 percent

Landform: Lava flow

Geomorphic position: Andesitic lava flows on mountainsides

 Major Soil Features and Properties Affecting Management

 Llaorock soil

 • Rock fragments on surface

• Rock fragments in soil profile

 Castlecrest soil

 • Sandy textures

• Low soil strength

• Dustiness if vegetation is removed

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