78 65—Unionpeak-Castlecrest complex, dry, 5 to 15 percent slope

65—Unionpeak-Castlecrest complex, dry, 5 to 15 percent slopes

 Map Unit Setting

 General location: Ashflows in the southeastern part of the park

Major land resource area (MLRA): 3

Elevation: 4,500 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

 Unionpeak and similar soils: 50 percent

Castlecrest and similar soils: 40 percent

Minor components: 10 percent

 Characteristics of the Unionpeak and Similar Soils

 Setting

 Landform: Ashflow

Geomorphic position: Ashflows on mountainsides and in valleys of Mount Mazama

Parent material: Ash, pumice, and andesite and dacite fragments

 Properties and qualities

 Slope: 5 to 15 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—(003XY704OR) Abies/Arctostaphylos nevadensis/Carex inops

 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 Castlecrest and Similar Soils

 Setting

 Landform: Ashflow

Geomorphic position: Ashflows on mountainsides and in valleys of Mount Mazama

Parent material: Ash and pumice

 Properties and qualities

 Slope: 5 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—(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

 Timbercrater soils

 Percentage of map unit: 10 percent

Landform: Ashfall

Geomorphic position: Pumice and ashfall deposits on mountainsides and in valleys of Mount Mazama

 Major Soil Features and Properties Affecting Management

 Unionpeak soil

 • Depth to hardpan

• Dustiness if vegetation is removed

• Low water-holding capacity

 Castlecrest soil

 • Sandy textures

• Low soil strength

• Dustiness if vegetation is removed

 

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