LOCATION HALF DOME CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, mesic Typic Dystroxerepts
TYPICAL PEDON: Half Dome on a 50 percent slope under canyon live oak, Douglas fir, and incense cedar at an elevation of 4,200 feet (1280.2 meters). (Colors are for dry soil unless otherwise stated. When described May 15, 1990, the soil was dry throughout.) The soil surface is partially covered with 30 percent boulders and 10 percent stones and cobbles.
Oi--0 to 3 inches (0 to 8 centimeters); litter, leaves, needles, and twigs. (0 to 4 inches [0 to 10 centimeters] thick)
A1--3 to 5 inches (8 to 13 centimeters); grayish brown (10YR 5/2) very bouldery sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure parting to weak medium granular; soft, very friable, non-sticky, slightly plastic; few medium and common very fine and fine roots; 5 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (1 to 10 inches [3 to 25 centimeters] thick)
A2--5 to 8 inches (13 to 21 centimeters); brown (10YR 5/3) gravelly sandy loam, dark brown (10YR 3/3) and very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure parting to weak medium granular; soft, very friable, non-sticky, slightly plastic; few medium and common very fine and fine roots; 15 percent gravel; slightly acid (pH 6.2); gradual wavy boundary. (3 to 30 inches [1 to 76 centimeters] thick)
Bw1--8 to 15 inches (20 to 38 centimeters); variegated yellowish brown (10YR 5/4) and light yellowish brown (10YR 6/4) cobbly sandy loam, dark brown (10YR 3/3) and dark yellowish brown (10YR 3/4) moist; weak medium and coarse subangular blocky structure; soft, very friable, non-sticky, slightly plastic; common very fine, fine, medium, and coarse roots; 15 percent gravel and 10 percent cobbles; moderately acid (pH 5.9); gradual wavy boundary. (4 to 10 inches [10 to 25 centimeters] thick)
Bw2--15 to 31 inches (38 to 79 centimeters) light yellowish brown (2.5Y 6/4) very cobbly sandy loam, variegated dark yellowish brown (10YR 4/4) and brown (10YR 4/3) moist; weak coarse subangular blocky structure; soft, very friable, non-sticky, slightly plastic; common very fine, fine, medium, and coarse roots; 15 percent gravel, 20 percent cobbles, and 5 percent stones; moderately acid (pH 5.9); gradual boundary. (4 to 16 inches [10 to 41 centimeters] thick)
C--31 to 63 inches (79 to 160 centimeters) pale yellow (2.5Y 7/4) very cobbly sandy loam, olive brown (2.5Y 4/4) moist; single grain; soft, very friable, non-sticky, non-plastic; 15 percent gravel, 20 percent cobbles, 5 percent stones; moderately acid (pH 6.0).
TYPE LOCATION: Mariposa County, California; northeast of Sentinel Creek, up Four Mile Trail, Yosemite National Park; Latitude 37 degrees 43 minutes 49 seconds north and Longitude 119 degrees 35 minutes 56 seconds west; USGS Half Dome, California Quadrangle, NAD 83.
RANGE IN CHARACTERISTICS: Depth of the solum is 15 inches (38 centimeters) to 35 inches (89 centimeters). The mean annual soil temperature is 52 to 56 degrees F (11.1 to 13.3 degrees C). The soil temperature exceeds 41 degrees F (5.0 degrees C) from March through November and exceeds 47 degrees F. (8.3 degrees C) from mid April through October. The difference between mean winter and mean summer soil temperatures is about 28 degrees F (19 degrees C). North facing slopes have the cooler soil temperatures while the south facing slopes have the warmer temperatures. The soil moisture control section is dry in all parts from early July to early November (140-160 days) and is moist in all parts from December to mid May. Base saturation is less than 60 percent.
A Horizon
Hue: 10YR (dry and moist)
Value: 5 (dry) and 3 (moist)
Chroma: 2 or 3 (dry and moist)
Texture of the fine earth fraction: loamy coarse sand, loamy sand, coarse sandy loam, or sandy loam
Clay content: 2 to 12 percent
Rock fragment content: 10 to 100 percent
Organic matter content: 0 to 10 percent in the upper 6 inches (15 centimeters); commonly 1 to 3 percent
Reaction: moderately acid to neutral
Other characteristics: some pedons have an AB or BA horizon
Bw Horizon
Hue: 10YR (dry) and (moist)
Value: 5 or 6 (dry) and 2 or 3 (moist)
Chroma: 3 or 4 (dry and moist)
Texture of the fine earth fraction: loamy coarse sand, loamy sand, coarse sandy loam, or sandy loam.
Clay content: 2 to 12 percent
Rock fragment content: 10 to 95 percent
Organic matter content: 0 to 4 percent
Reaction: moderately acid to neutral
C Horizon
Hue: 10YR (dry and moist)
Value: 5 (dry) and 3 (moist)
Chroma: 4 to 6 (dry) and 3 or 4 (moist)
Texture of the fine earth fraction: loamy coarse sand, loamy sand, or sandy loam
Clay content: 1 to 12 percent
Rock fragment content: 5 to 85 percent
Organic matter content: 0 to 1 percent
Reaction: moderately acid to neutral
COMPETING SERIES: These are the Atring, Barpeak, Beekman, Farber, Firmountain, Forgay, Geppert, Hartless, Hilltish, Kanid, Straight, Vena, and Woodin soils. Atring, Beekman, Firmountain, Geppert, Hilltish and Straight soils are moderately deep. Baldhill soils are dry for 60 to 75 days. Barpeak soils have 18 to 25 percent clay in the particle-size control section. Farber soils are dry for 45 to 60 consecutive days. Hartless soils have 10 to 18 percent clay in the particle size control zone. Forgay soils have mixed rock parent material. Kanid soils have 18 to 35 percent clay in the particle-size control section. Vena soils are dry for 60 to 90 consecutive days. Woodin soils have less than 15 percent very coarse plus coarse sand and have a lithic contact between 20 to 40 inches (51 to 102 centimeters).
GEOGRAPHIC SETTING: Half Dome soils are on mountain slopes, mountainsides, moraines, mountain valleys, and drainageways. Slope is 5 to 60 percent. These soils formed in colluvium and/or till derived from granitoid rocks. Elevation is 3,793 to 6,525 feet (1,156.0 to 1,988.9 meters). The climate is subhumid with warm dry summers and cool moist winters. Mean annual precipitation is 35 to 43 inches (889 to 1,092 millimeters), some of which falls as snow. The mean annual temperature is 48 to 55 degrees F (8.9 to 13.0 degrees C). The mean January temperature is about 36 degrees F (2.2 degrees C). The mean July temperature is about 72 degrees F (22.2 degrees C). The frost-free period is 100 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Happyisles soils on alluvial fans, fan aprons, flood plains, terraces, mountain valleys and drainageways.
DRAINAGE AND PERMEABILITY: Well drained; low or medium runoff; hydraulic conductivity is high or very high.
USE AND VEGETATION: This soil is used for watershed and wildlife habitat. The vegetation is live oak, Ponderosa pine, Douglas fir, incense cedar, black oak, and bay laurel.
DISTRIBUTION AND EXTENT: West side of the central Sierra Nevada Range, California. The soils are not extensive. MLRA is 22A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Yosemite National Park, California 2007. Series is named after prominent mountain peak in Yosemite Valley.
REMARKS: All lab data from soils in the Yosemite Valley Part Soil Survey indicate isotic mineralogy. Half Dome soils have an ochric epipedon and a cambic horizon. The cambic horizon has texture in the fine earth fraction of coarse sandy loam or sandy loam.