LOCATION YORKTREE CA
Established Series
Rev. SJB-CEJ-JJJ
12/2022
YORKTREE SERIES
The Yorktree series consists of very deep, well drained soils formed in material weathered from graywacke, shale, siltstone or sandstone. Yorktree soils are deep to lithic material with spacing between cracks less than 10 centimeters apart. Yorktree soils are on hills and mountains and have slopes of 15 to 75 percent. The mean annual precipitation is about 1065 millimeters (42 inches) and the mean annual temperature is about 14 degrees C (57 degrees F).
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Ultic Argixerolls
TYPICAL PEDON: Yorktree loam--on an east facing concave slope of 34 percent under black oak, white oak and wild oats at 440 meters (1,440 feet) elevation. (Colors are for dry soil unless otherwise stated. When described on July 13, 1978, the soil was dry to a depth of 46 centimeters and moist below.)
A1--0 to 13 centimeters (0 to 5 inches); brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; common very fine and fine and few medium roots; many very fine and fine and few coarse tubular pores; neutral (pH 6.6); clear wavy boundary. (5 to 15 centimeters thick)
A2--13 to 31 centimeters (5 to 12 inches); brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; moderate medium angular and subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine, fine and medium and few coarse roots; many very fine and fine and few coarse tubular pores; few faint silt flows; moderately acid (pH 5.8); clear wavy boundary. (13 to 20 centimeters thick)
2AB--31 to 46 centimeters (12 to 18 inches); yellowish brown (10YR 5/4) gravelly loam, dark brown (10YR 3/3) moist; moderate fine and medium subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; few very fine through coarse roots; many very fine and fine tubular pores; few faint silt flows; 25 percent 35 to 75 millimeter gravel and 5 percent 75 to 175 millimeters cobbles; moderately acid (pH 5.8); clear wavy boundary. (13 to 20 centimeters thick)
2Bt1--46 to 61 centimeters (18 to 24 inches); brown (10YR 5/3) gravelly clay loam, dark brown (10YR 3/3) moist, brown (10YR 4/3) moist crushed; strong fine subangular blocky structure; very hard, very firm, moderately sticky and moderately plastic; few fine and common very fine and coarse roots; many very fine and fine and common medium tubular pores; common faint clay films in pores and on peds; 25 percent 35 to 75 millimeter gravel and 5 percent 75 to 175 millimeters cobbles; moderately acid (pH 6.0); clear wavy boundary. (10 to 18 centimeters thick)
2Bt2--61 to 107 centimeters (24 to 42 inches); brown (10YR 5/3) clay, dark brown (10YR 3/3) moist, brown (10YR 4/3) moist crushed; moderate medium subangular blocky structure parting to moderate fine angular blocky; very hard, very firm, moderately sticky and moderately plastic; few very fine, fine and coarse and common medium roots; many very fine and fine tubular pores; many distinct clay films in pores and on peds; slickensides; 10 percent 10-20 millimeter gravel; neutral (pH 6.6); gradual wavy boundary. (46 to 64 centimeters thick)
2Bt3--107 to 130 centimeters (42 to 51 inches); brown (10YR 5/3) gravelly clay, very dark grayish brown (10YR 3/2) moist and brown (10YR 4/3) moist crushed; moderate fine and medium subangular blocky structure; very hard, very firm, moderately sticky and moderately plastic; common very fine roots; many very fine and common fine tubular pores; many distinct clay films in pores and on peds; 25 percent 35-75 millimeter gravel; slightly acid (pH 6.4); clear wavy boundary. (18 to 28 centimeters thick)
C--130 to 200 centimeters (51 to 79 inches); gravel: fractured hard graywacke, fractures are 2 to 8 centimeters apart.
TYPE LOCATION: Mendocino County, California; 100 feet west and upslope of Pine Ridge Road, 1.0 miles south of the intersection of Pine Ridge and Low Gap Roads 1,800 feet north and 2,200 feet east of the southwest corner section 15, T.15 N., R.13 W.
RANGE IN CHARACTERISTICS:
Soil moisture: The soil between a depth of 15 to 46 centimeters is dry in all parts from July through October and is moist in all parts from December through April. The soil has a xeric soil moisture regime.
Soil temperature: 10 to 15 degrees C (50 degrees to 59 degrees F).
Depth to lithic material with fractures less than 10 centimeters apart: 100 to 150 centimeters (40 to 60 inches)
Base saturation by sum of cations: 60 to 90 percent in the upper 75 centimeters and is 60 to 75 percent in some subhorizon.
A stone line occurs in most pedons between a depth of 10 and 24 inches. It contains 15 to 30 percent 2 to 75 millimeter gravel and 5 to 10 percent 75 to 150 millimeter cobbles.
Mollic epipedon: 25 to 46 centimeters thick.
Particle size control section (weighted average):
Rock fragments: 5 to 35 gravel
Clay content: 35 to 50 percent
Base saturation (sum): 75 to 95 percent
A horizon: upper part
Value: 4 or 5 dry, 2 or 3 moist
Chroma: 2 or 3, dry or moist
Texture fine earth fraction: loam, clay loam
Clay content: 20 to 35 percent
Rock fragments: 2 to 10 percent gravel
Organic matter content: 1 to 5 percent
Reaction: moderately acid to neutral
A horizon: lower part
10YR 5/4
Texture fine earth fraction: loam, clay loam
Clay content: 20 to 35 percent
Rock fragments: 2 to 30 percent
Organic matter content: 1 to 5 percent
Reaction: moderately acid to neutral
A stone line occurs in most pedons with 5 to 10 percent cobbles
2Bt horizon:
Hue: 10YR, 7.5YR, 2.5Y
Value: 4 through 6 dry, 3 through 5 moist
Chroma: 2 through 4, dry or 4 moist
Texture: clay loam, clay
Clay content: 24 to 50 percent
Rock fragments: 5 to 35 percent
Silt content: 15 to 25 percent
C horizon: Texture: gravel
Rock fragments: 90 to 100 percent
COMPETING SERIES: This is the
Helvetia (OR) series. Helvetia soils are dry for 45 to 75 days, have more than 40 percent silt, and lack coarse fragments in the particle-size control section.
GEOGRAPHIC SETTING: Yorktree soils are on ridgetops and sideslopes of hills and mountains and have slopes of 15 to 75 percent. The soils formed in material weathered from graywacke, sandstone, siltstone, and shale. Elevations are 152 to 1220 meters (500 to 4,000 feet). The climate is subhumid with hot dry summers and cool moist winters. Mean annual precipitation varies from 900 to 1800 millimeters (35 to 70 inches). Mean January temperature is 7 degrees C (44 degrees F), mean July temperature is 22 degrees C (72 degrees F), annual temperature is 10 to 15 degrees C (50 degrees to 59 degrees F). Frost-free period is 125 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Hopland,
Neuns,
Speaker, Frogwoman,
Tyson, Witherall,
Woodin and
Yorkville soils. Hopland, Neuns, Speaker, Frogwoman, Witherall, and Woodin soils lack mollic epipedons. Tyson soils are skeletal and less than 100 centimeters deep. Yorkville soils have a thermic soil temperature regime.
DRAINAGE AND PERMEABILITY: Well drained; medium to very high runoff; slow permeability.
USE AND VEGETATION: Used for livestock grazing, watershed, wildlife habitat, recreation, and limited firewood production. Vegetation is Oregon white oak, California black oak, blue oak, live oak, poison-oak, pacific madrone, Douglas-fir, blue wild rye, wild oats, dogtail and tarweed.
DISTRIBUTION AND EXTENT: Northern California in the Coast Range. The soils are not extensive. MLRA 5.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lake County, California, 1983.
REMARKS:
The depth class was changed to reflect the fracture spacing in the lithic material in January 2008. - ET.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the surface layer from 0 to 31 centimeters (A1, A2 horizons)
Argillic horizon - the zone from 46 to 130 centimeters (2Bt1, 2Bt2, 2Bt3 horizons)
Lithic material - the boundary at 130 inches (C layer)
ADDITIONAL DATA: NSSL Pedon S78CA-045-113 (Type Location)
National Cooperative Soil Survey
U.S.A.