64 51—Sunnotch-Unionpeak complex, 15 to 35 percent slopes

51—Sunnotch-Unionpeak complex, 15 to 35 percent slopes

 Map Unit Setting

 General location: Ash and cinder flows on side slopes of Mount Mazama

Major land resource area (MLRA): 3

Elevation: 5,000 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 50 days

 Map Unit Composition

 Sunnotch and similar soils: 50 percent

Unionpeak and similar soils: 40 percent

Minor components: 10 percent

 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: 15 to 35 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 Unionpeak and Similar Soils

 Setting

 Landform: Ashflow

Geomorphic position: Ashflow material on side slopes of Mount Mazama

Parent material: Pumice, ash, and dacite and andesite fragments

 Properties and qualities

 Slope: 15 to 35 percent

Percentage of surface covered with stones and boulders: None

Restrictive feature: Duripan at a depth of 20 to 40 inches

Drainage class: Somewhat excessively drained

Permeability: Moderately rapid or rapid

Flooding: Not present

Water table: Not present

Ponding: Not present

Available water capacity: About 4.3 inches

 Interpretive groups

 Ecological site: Forestland—(003XY706OR) Tsuga mertensiana/Luzula glabrata var. hitchcockii

 Typical profile

 Oi—0 to 1 inch; slightly decomposed plant material

A1—1 inch to 4 inches; ashy sandy loam

A2—4 to 8 inches; ashy loamy sand

Bw—8 to 30 inches; gravelly ashy loamy sand

Bqm—30 to 45 inches; cemented ashy loamy sand

C—45 to 65 inches; gravelly ashy loamy sand

 Characteristics of the Minor Components

 Castlecrest soils

 Percentage of map unit: 5 percent

Landform: Ashflow

Geomorphic position: Ashflow material on side slopes of Mount Mazama

 Timbercrater soils

 Percentage of map unit: 5 percent

Landform: Ashflow

Geomorphic position: Ashfall and ashflow material on side slopes of Mount Mazama

 Major Soil Features and Properties Affecting Management

 Sunnotch soil

 • Rock fragments in soil profile

• Sandy textures

 Unionpeak soil

 • Depth to hardpan

• Dustiness if vegetation is removed

• Low water-holding capacity

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