LOCATION WEITCHPEC CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, magnesic, mesic Typic Haploxerepts
TYPICAL PEDON: Weitchpec gravelly sandy loam - mixed conifers (Colors are for dry soil unless otherwise noted.)
A--0 to 5 centimeters (0 to 2 inches); grayish brown (10YR 5/2) gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium platy structure; soft, very friable, nonsticky and nonplastic; few roots; many very fine interstitial pores; 30 percent gravel; neutral (pH 7.0); abrupt smooth boundary. (5 to 25 centimeters thick).
Bt--5 to 30 centimeters (2 to 12 inches); strong brown (7.5YR 5/6) very gravelly sandy loam, brown (7.5YR 4/4) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine, few medium and coarse roots; many very fine interstitial pores; common distinct clay films on rock fragments; 50 percent gravel; slightly alkaline (pH 7.5); gradual smooth boundary. (20 to 38 centimeters thick).
BCt--30 to 56 centimeters (12 to 22 inches); pale brown (10YR 6/3) very gravelly sandy loam, brown (10YR 4/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine, medium and coarse roots; many very fine interstitial pores; few distinct clay films on rock fragments; 50 percent gravel; slightly alkaline (pH 7.5); abrupt irregular boundary. (25 to 38 centimeters thick).
R--56 to 77 centimeters (22 to 30 inches); Fractured serpentine rock.
TYPE LOCATION: Trinity County, California; 1/4 mile west of Lucky Lake on jeep trail to Fern Point; NE1/4 SE1/4 section 16, T. 25 N., R. 11 W.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil between the depths of 20 (8 inches) and 61 centimeters (24 inches) is usually dry in all parts from June 15 to October 15 and moist in all parts from November 15 to April 15. The soils have a xeric moisture regime.
Soil temperature: The mean annual soil temperature is 11 to 14 degrees C (52 to 57 degrees F). The difference between mean summer and mean winter temperature is 6 to 10 degrees C.
Base saturation is 60 to 80 percent (ammonium acetate).
Depth to lithic contact: 50 to 102 centimeters (20 to 40 inches)
The particle-size control section:
Rock fragments: 35 to 60 percent
Clay content: 18 to 35 percent
Some pedons have O horizons.
O horizon
Hue: 10YR.
Value: 2 through 6 dry and moist.
Chroma: 1 through 4 dry and moist.
Texture: slightly decomposed organic material.
Wood fragments: 0 to 35 percent.
Reaction: moderately to very strongly acid.
A horizon
Hue: 5YR, 7.5YR, 10YR, or 2.5Y.
Value: 5 through 7 dry, 3 through 6 moist.
Chroma: 2 through 6 dry, 2 through 6 moist.
Texture of fine earth: sandy loam, loam, silt loam, sandy clay loam or clay loam.
Rock fragments: 10 to 35 percent gravel and 0 to 20 percent cobbles.
Clay content: 15 to 30 percent.
Reaction: slightly alkaline to moderately acid.
Bt horizon
Hue: 5YR, 7.5YR, 10YR, or 2.5Y.
Value: 5 through 8 dry, 4 or 5 moist.
Chroma: 2 through 8 dry, 4 through 8 moist.
Texture of fine earth: sandy loam, sandy clay loam, silt loam, silty clay loam, loam or clay loam.
Rock fragments: 35 to 60 percent gravel, 0 to 20 percent cobbles and 0 to 20 percent stones.
Clay content: 15 to 35 percent.
Reaction: slightly alkaline to moderately acid.
Some pedons have C horizons.
C horizon
Hue: 5YR, 7.5YR or 10YR.
Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 2 through 8 dry, 4 through 8 moist.
Texture of fine earth: sandy clay loam, loam or clay loam.
Rock fragments: 35 to 60 percent gravel, 0 to 20 percent cobbles and 0 to 20 percent stones.
Clay content: 23 to 35 percent.
Reaction: slightly alkaline to moderately acid.
COMPETING SERIES: At this time there are no other series in this family.
GEOGRAPHIC SETTING: Weitchpec soils are on steep and very steep mountain slopes. Slopes are 5 to 75 percent. Elevations are 259 to 1804 meters (850 to 5500 feet). The soils formed in material weathered from serpentinized rocks. The climate is humid with warm, dry summers and cool, wet winters. Mean annual precipitation is 760 to 3050 millimeters (30 to 120 inches). Mean January temperature is 3 to 5 degrees C (38 to 41 degrees F.), and mean July temperature is 18 to 24 degrees C (65 to 75 degrees F.). Mean annual temperature is 10 to 13 degrees C (50 to 55 degrees F). Frost-free season is estimated to be about 90 to 230 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gasquet, Jayel, Oragran, and Walnett soils. The Gasquet and Jayel soils are fine. Oragran soils are 20 to 50 centimeters (10 to 20 inches) to a lithic contact. Walnett soils are greater than 152 centimeters (>60 inches) to a lithic contact. Gasquet and Walnett soils are in concave to linear positions and are on more stable positions on mountain slopes. Jayel and Oragran soils are on very strongly convex positions.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; high to very high runoff; moderately high to moderately low saturated hydraulic conductivity.
USE AND VEGETATION: Used for timber production and watershed. Native vegetation is Jeffrey pine, Douglas-fir, sugar pine ponderosa pine, incense cedar, tanoak, madrone, and manzanita.
DISTRIBUTION AND EXTENT: North part of the Coast Ranges and Klamath Mountains in California and may occur in Oregon. The soils are not extensive. MLRA is 5.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Trinity County (Mendocino National Forest Area), California, 1971.
REMARKS: The Weitchpec soils were formerly classified as Regosols. Since most pedons have many coarse fragments, the series is now defined as a member of the loamy-skeletal family.
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface to 5 centimeters (2 inches) (A horizon).
Cambic horizon - the zone from 5 to 30 centimeters (2 to 12 inches) (Bt horizon). Particle-size
control section - the zone from 25 to 56 centimeters (10 to 22 inches) (Bt and BCt horizon).
Lithic contact - the boundary at about 56 centimeters (22 inches) (R).
ADDITIONAL DATA:
Source: 10th Edition of the Keys to Soil Taxonomy.