Detailed Soil Map Units
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24—Grousehill-Llaorock complex, dry, 0 to 30 percent slopes
Map Unit Setting
General location: Side slopes of mountains and ridges in the southeastern part of the park
Major land resource area (MLRA): 3
Elevation: 5,500 to 6,000 feet
Average annual precipitation: 45 to 60 inches
Average annual air temperature: 38 to 42 degrees F
Frost-free period: 10 to 50 days
Map Unit Composition
Grousehill and similar soils:
65 percent
Llaorock and similar soils: 20 percent
Minor components: 15 percent
Characteristics of the Grousehill and Similar Soils
Setting
Landform: Ground moraine
Geomorphic position: Glacial moraines on ridges and mountainsides
Parent material: Ash over glacial till
Properties and qualities
Slope: 0 to 30 percent
Percentage of surface covered with stones and boulders: 3 percent
Restrictive feature: Duripan at a depth of 20 to 40 inches
Drainage class: Moderately well drained
Permeability: Moderate
Flooding: Not present
Water table: Present (see
table 20)
Ponding: Not present
Available water capacity: About 12.8 inches
Interpretive groups
Ecological site: Forestland—(003XY703OR) Abies/Carex inops
Typical profile
Oi—0 to 3 inches; slightly decomposed plant material
A—3 to 10 inches; gravelly medial loam
Bw1—10 to 31 inches; very cobbly medial loam
Bw2—31 to 39 inches; very cobbly medial loam
Bqm—39 to 56 inches; moderately cemented duripan
Characteristics of the Llaorock and Similar Soils
Setting
Landform: Stratovolcano
Geomorphic position: Side slopes of glaciated valleys
Parent material: Ash mixed with residuum and colluvium derived from andesite
Properties and qualities
Slope: 0 to 30 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—(003XY704OR) Abies/Carex inops
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
Castlecrest soils
Percentage of map unit: 10 percent
Landform: Ashfall
Geomorphic position: Ashfall deposits on mountainsides
Rock outcrop
Percentage of map unit: 5 percent
Landform: Stratovolcano
Geomorphic position: Side slopes of glaciated valleys
Major Soil Features and Properties Affecting Management
Grousehill soil
• Rock fragments on surface
• Rock fragments in soil profile
• Depth to hardpan
• Wetness
Llaorock soil
• Rock fragments on surface
• Rock fragments in soil profile
