LOCATION HIGHOAKS CA

Established Series
Rev: BAL/ACF/ET
10/2016

HIGHOAKS SERIES

The Highoaks series consists of very deep, well drained soils formed in colluvium and residuum derived from sandstone and mudstone. These soils are on mountains and have slopes of 9 to 50 percent. Mean annual precipitation is 1500 millimeters (59 inches) and the mean annual temperature is 12 degrees C (54 degrees F).

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Xeric Palehumults

TYPICAL PEDON: Highoaks gravelly loam - under a stand of California black oak and annual and perennial grasses. When described on July 28, 2004, the soil was dry throughout. (Colors are for dry soil unless otherwise stated).

Oi--0 to 2 centimeters (0 to 1 inch); very dark gray (10YR 3/1) slightly decomposed plant material consisting of needles and leaves of Oregon white oak, black (10YR 2/1) moist; about 100 percent fiber, 80 percent rubbed; few very fine roots; many fine irregular pores; slightly acid (pH 6.4); abrupt smooth boundary. (0 to 10 centimeters thick)

A--2 to 22 centimeters (1 to 9 inches); very dark grayish brown (10YR 3/2) gravelly loam, black (10YR 2/1) moist; weak medium subangular blocky structure parting to strong very fine granular; soft, very friable, nonsticky and nonplastic; many very fine through medium and common coarse roots; many fine and medium tubular pores; 30 percent gravel; slightly acid (pH 6.4); clear smooth boundary.(15 to 35 centimeters thick)

Bt1--22 to 51 centimeters (9 to 20 inches); yellowish brown (10YR 5/4) silty clay loam, dark yellowish brown (10YR 4/4) moist; strong fine and medium subangular blocky structure; slightly hard, friable, very sticky and very plastic; common fine and medium roots; many fine and medium, few coarse tubular pores; few faint clay films on all faces of peds; 10 percent gravel; very strongly acid (pH 4.8); clear smooth boundary.

Bt2--51 to 80 centimeters (20 to 31 inches); dark yellowish brown (10YR 4/4) gravelly silty clay loam, brown (10YR 4/3) moist; strong fine and medium subangular blocky structure; slightly hard, friable, very sticky and very plastic; many fine, and medium roots; many fine and medium, common coarse tubular pores; common distinct clay films on all faces of peds; 30 percent gravel; very strongly acid (pH 4.8); clear smooth boundary. (combined thickness of upper Bt horizon is 50 to 150 centimeters)

Bt3--80 to 107 centimeters (31 to 42 inches); light olive brown (2.5Y 5/4) gravelly silty clay loam, olive brown (2.5Y 4/3) moist; strong fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many fine and medium roots; many medium and common coarse tubular pores; common distinct clay films on all faces of peds; 20 percent gravel; very strongly acid (pH 4.8); clear smooth boundary.

Bt4--107 to 127 centimeters (42 to 50 inches); olive brown (2.5Y 4/4) very paragravelly silty clay loam, dark olive brown (2.5Y 3/3) moist; strong fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; many fine and medium roots; many fine and medium, common coarse tubular pores; common distinct clay films on all faces of peds; 50 percent paragravel; very strongly acid (pH 4.8); clear smooth boundary. (combined thickness of lower Bt horizons is 0 to 50 centimeters)

BCt--127 to 160 centimeters (50 to 63 inches); olive brown (2.5Y 4/4) extremely paragravelly silty clay loam, dark olive brown (2.5Y 3/3) moist; weak fine subangular blocky structure; slightly hard, friable, very sticky and very plastic; common fine and medium roots; common coarse tubular pores; few faint clay films on all faces of peds; 90 percent paragravel; very strongly acid (pH 4.8). (0 to 50 centimeters thick)

TYPE LOCATION: Humboldt County, California; Kinsey Ridge; USGS Board Camp Mountain, Quadrangle, Ca; 41.04857 latitude and -123.709506 longitude; UTM Zone 10 440891mE, 4509997mN, NAD 83.

RANGE IN CHARACTERISTICS:

Soil moisture: The soil moisture control section is dry from July 1st to October 15th and moist in all parts from November 15 to June 1st. This soil has a xeric soil moisture regime.

Soil temperature: The mean annual soil temperature is 10 to 15 degrees C (50 to 59 degrees F). The difference between the mean summer and mean winter temperature is 6 degrees C or greater. This soil has a mesic soil temperature regime

Base saturation (by sum of cations) is less than 35 percent 125 centimeters below the top of the argillic horizon.

Organic carbon is 12kg or more in the upper cubic meter of the mineral soil or the upper 15 cm of the argillic has 0.9 percent or more organic carbon.

Surface fragments: 0 to 5 percent gravel

Particle Size Control Section (weighted average):
Clay: 27 to 35 percent
Rock fragments: 0 to 35 percent gravel.

A horizons
Hue: 10YR or 2.5Y
Value: 3 through 5 dry; 2 through 4 moist
Chroma: 2 through 4 dry; 1 through 3 moist
Reaction: very strongly acid to neutral
Texture of the fine earth fraction: loam

Clay content: 12 to 25 percent
Rock fragments: 15 to 35 percent gravel

Upper Bt horizons
Hue: 10YR or 2.5Y
Value: 3 through 5, dry or moist
Chroma: 2 through 4, dry or moist
Reaction: very strongly acid to moderately acid
Texture of the fine earth fraction: silty clay loam or clay loam
Clay content: 27 to 35 percent
Rock fragments: 0 to 35 percent gravel

Lower Bt horizons
Hue: 10YR or 2.5Y
Value: 3 through 5, dry or moist
Chroma: 2 through 4, dry or moist
Reaction: very strongly acid to moderately acid
Texture of the fine earth fraction: silty clay loam or clay loam
Clay content: 30 to 40 percent
Rock fragments: 5 to 35 percent gravel
Pararock fragments: 0 to 50 percent paragravel

Some pedons have C horizons

C horizons
Hue: 10YR or 2.5Y
Value: 3 through 5, dry or moist
Chroma: 2 through 4, dry or moist
Reaction: very strongly acid to moderately acid
Texture of the fine earth fraction: silty clay loam
Clay content: 30 to 40 percent
Pararock fragments: 60 to 90 percent paragravel

COMPETING SERIES: These are the Buckpeak(WA), Centralia and Flyat series. The Buckwheat and Centralia soils have 7.5YR colors throughout the subsurface horizons. Flyat has an Umbric epipedon.

GEOGRAPHIC SETTING: These soils occur on mountain slopes with slopes of 9 to 50 percent. They are on linear and convex slope positions at elevations of 35 to 1200 meters (115 to 3937 feet). These soils formed in colluvium and residuum derived from sandstone and mudstone. The climate is subhumid with warm dry summers and cool moist winters. The mean annual precipitation is 1250 to 2030 millimeters (49 to 80 inches). Mean annual air temperature is about 12 degrees C (54 degrees F). Mean summer temperature is 14 degrees C (58 degrees F) and the mean winter temperature is 7 degrees C (44 degrees F).The frost free period is about 150 to 250 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Mudhorse and Noisy series. Mudhorse soils are moderately well drained with redoximorphic features between 50 and 100 centimeters from the soil surface. Noisy soils are loamy-skeletal with greater than 35 percent rock fragments in the particle size control section. The Mudhorse soils are generally found in concave slope positions. The Noisy soils are generally found in slightly to strongly convex slope positions.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well-drained; high runoff; moderately high to moderately low saturated hydraulic conductivity.

USE AND VEGETATION: This soil is mostly used for livestock grazing, wildlife habitat, and watershed. Natural vegetation is Oregon white oak with an understory of bristly dogtail grass, woodland strawberry, creeping snowberry and poison oak. Douglas-fir invades readily in the absence of fire and grazing.

DISTRIBUTION AND EXTENT: Siskyou-Trinity Area, MLRA 5. The name is coined. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Humboldt Del Norte Area, California, 2007.

REMARKS: Diagnostic horizons and features include:

1. Ochric horizon - the zone from 0 to 24 centimeters (Oi & A horizons)
2. Argillic horizon - the zone from 22 to 160 centimeters (Bt1, Bt2, Bt3, Bt4, BCt horizons)
3. Particle size control section - the zone from 22 to 72 centimeters, averaging (by weight) 30 percent clay and 18 percent rock fragments.

ADDITIONAL DATA: NASIS Pedon ID: 04CA023605040

Soil classified using Keys to Soil Taxonomy, 12th edition.

National Cooperative Soil Survey
U.S.A.