LOCATION DEVILSCREEK             CA

Established Series
REV: JL/JPS/ET
07/2016

DEVILSCREEK SERIES

The Devilscreek series consists of very deep, moderately well drained soils that formed in colluvium from schist. Devilscreek soils are on mountains and have slopes of 30 to 75 percent. The mean annual precipitation is about 2160 millimeters (85 inches) and the mean annual temperature is about 12 degrees C (54 degrees F).

TAXONOMIC CLASS: Fine-loamy, mixed, semiactive, isomesic Oxyaquic Dystrudepts

TYPICAL PEDON: Devilscreek gravelly loam - on a north-facing uniform slope of 68 percent under redwood, hemlock, tanoak, dogwood, Pacific rhododendron, salal, swordfern, deer fern and five-finger fern at 152 meters (500 feet) elevation. (Colors are for moist soil unless otherwise stated. When described July 22, l983, the soil was moist throughout.)

Oi--0 to 3 centimeters (0 to 1 inch); slightly decomposed redwood twigs, leaves and bark, tanoak leaves and fern fronds; very strongly acid (pH 4.5); clear smooth boundary. (0 to 12 centimeters thick)

A--3 to 15 centimeters (1 to 6 inches); light yellowish brown (10YR 6/4) gravelly loam, dark yellowish brown (10YR 4/6) dry; weak medium granular and subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots throughout; common fine irregular and many very fine and fine tubular pores; 33 percent gravel; strongly acid (pH 5.4); gradual wavy boundary. (5 to 56 centimeters thick)

BA--15 to 35 centimeters (6 to 14 inches); yellowish brown (10YR 5/8) clay loam, light yellowish brown (10YR 6/4) dry; moderate coarse subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; common very fine, fine and medium and few coarse roots throughout; common very fine and fine tubular pores; 6 percent gravel; strongly acid (pH 5.4); gradual wavy boundary. (0 to 28 centimeters thick)

Bw1--35 to 54 centimeters (14 to 21 inches); strong brown (7.5YR 5/6) clay loam, brownish yellow (10YR 6/6) dry; moderate coarse and very coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, and medium and few coarse roots throughout; common very fine, fine and medium tubular pores; 6 percent gravel; strongly acid (pH 5.5); gradual wavy boundary.

Bw2--54 to 75 centimeters (21 to 30 inches); yellowish brown (10YR 5/8) cobbly clay loam, yellowish brown (10YR 5/6) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine, medium, and coarse roots throughout; few very fine and fine tubular pores; 12 percent gravel and 10 percent cobbles; strongly acid (pH 5.2); gradual smooth boundary. (Combined thickness of Bw horizons is 25 to 100 centimeters)

Cg1--75 to 95 centimeters (30 to 37 inches); gray (2.5Y 5/1) very gravelly silt loam, light gray (2.5Y 7/2) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots throughout; few very fine and fine tubular pores; common medium prominent masses of iron accumulations, brownish yellow (10YR 6/6), yellowish brown (10YR 5/8) moist; 40 percent gravel and 10 percent cobbles; strongly acid (pH 5.2); clear wavy boundary.

Cg2--95 to 171 centimeters (37 to 67 inches); variegated olive (5Y 5/3) and gray (5Y 6/1) very gravelly silt loam, light gray (5Y 7/1) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine, fine, medium and coarse roots throughout; few very fine tubular pores; common medium prominent masses of iron accumulations, strong brown (7.5YR 5/6) and common medium prominent strong brown (7.5YR 5/8) moist; 38 percent gravel and 10 percent cobbles; strongly acid (pH 5.1). (Combined thickness of Cg horizons is 25 to 150 centimeters)

TYPE LOCATION: Redwood National Park, Humboldt County, California; located approximately 22 kilometers southeast of the town of Orick, 76 meters due east of G-6 Road bridge over Tom McDonald Creek in the northwest corner of the southeast quarter, northeast quarter, Section 11, T. 9 N., R. 1 E., WGS84 Decimal degrees 41.1886694 latitude and -124.0236806 longitude; HBLM, USGS Rodger's Peak Quadrangle; UTM Zone 10 414152mE 4560206mN; NAD83.

RANGE IN CHARACTERISTICS:

Soil moisture: The soil is usually moist in all parts in the soil moisture control section in most years, but becomes nearly dry in the upper part from about September 15 to October 15 in most years.The soils have an udic moisture regime and an oxyaquic regime subclass. A seasonal water table is present for 20 or more consecutive days or 30 or more cumulative days in most years within the zone from 50 to 100 centimeters (20 to 39 inches).

Soil temperature: The mean annual soil temperature is 10 degrees to 13 degrees C (50 to 52 degrees F). The difference between mean summer and winter temperature is 2 to 4 degrees C. The soil temperature regime is isomesic.

Depth to redoximorphic features is 50 to 100 centimeters.

Reaction is strongly acid throughout.

Base saturation is less than 50 percent in the top 100 centimeters but in some profiles, increases to above 50 percent in the Cg1 and Cg2.

Particle-Size Control Section (weighted average):

Rock fragments: 3 to 25 percent gravel and 0 to 15 percent cobbles.
Clay content: 25 to 35 percent.

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 slightly acid.

A horizon

Hue: 10YR
Value: 4 through 7 dry, 3 or 4 moist.
Chroma: 4 through 6 dry, 4 through 6 moist.
Texture of fine earth: loam.
Rock fragments: 15 to 35 percent gravel and 0 to 5 cobbles.
Clay content: 25 to 27 percent.

Bw horizon

Hue: 7.5YR or 10YR.
Value: 5 through 8 dry, 4 through 6 moist.
Chroma: 4 through 6 dry, 4 through 8 moist.

Texture of fine earth: loam or clay loam.
Rock fragments: 3 to 20 percent gravel and 0 to 15 cobbles.
Clay content: 27 to 35 percent.

Cg or C horizons

Hue: 2.5Y, 5Y, or N.
Value: 4 through 8 dry, 4 through 6 moist.
Chroma: / through 3 dry, / through 3 moist.
Texture of fine earth: silt loam.
Rock fragments: 35 to 50 percent gravel and 0 to 10 cobbles.
Clay content: 10 to 25 percent.

Redoximorphic concentrations:
Type: fine and medium iron-manganese masses in the matrix, iron stains lining root channels and/or pores
Quantity: common to many
Hue: 7.5YR or 10YR.
Value: 5 or 6 moist.
Chroma: 6 or 8 moist.

COMPETING SERIES: At this time there are no other series in this family.

GEOGRAPHIC SETTING: Devilscreek soils are on mountain slopes near drainage headwaters. Slopes are 30 to 75 percent. Elevations are 15 to 757 meters (45 to 2480 feet). These soils formed in colluvium weathered from schist. The climate is humid with cool, foggy summers and cool, rainy winters. Mean annual precipitation is 1780 to 2550 millimeters (70 to 100 inches). Mean January temperature is about 9 degrees C; mean July temperature is about 14 degrees C; and mean annual temperature is 10 to 13 degrees C (50 to 55 degrees F). Frost-free season is about 240 to 300 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Coppercreek and the Panthercreek soils. Coppercreek soils have an argillic horizon and lack redoximorphic concentrations. Panthercreek soils have loamy-skeletal control sections. The Panthercreek soils are near creeks downstream from the headwaters. The Coppercreek soils are on drier slopes above the Devilscreek soils.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Moderately well drained; high runoff; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: This soil has been used for commercial timber production, wildlife, and watershed. Natural vegetation includes redwood, western hemlock, tanoak, Pacific rhododendron, California huckleberry, swordfern, and deer fern.

DISTRIBUTION AND EXTENT: California Coastal Redwood Belt; MLRA 4B. The series is not extensive.

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

SERIES ESTABLISHED: Humboldt County, California, Redwood National Park 1983. The source of the name is from Devils Creek, Redwood National Park, California.

REMARKS: Diagnostic horizons and features recognized in this pedon are:

1. Ochric epipedon - the zone from 0 to 18 centimeters (A and upper BA horizons).
2. Cambic horizon - the zone from 15 to 75 centimeters (BA, Bw1 & Bw2 horizons)
3. Redoximorphic features - in the zone from 75 to 171 centimeters (Cg1 &
Cg2).
4. Dystrudepts feature - base saturation less than 60 percent, by ammonium acetate, throughout the profile.
5. Oxyaquic Dystrudepts - seasonal water table, reduced matrix and aquic conditions for more than 30 days in most years within the zone from 75 to 171 centimeters (Cg1 & Cg2 horizons)
6. Particle-size control section - the zone from 25 to 100 centimeters, averages 26 percent clay, by weight, and 28 percent rock fragments, by volume. CEC/clay ratio averages 0.38.

ADDITIONAL DATA: Soil sample 82-RNP-8 (physical properties) and 83-RNP-11 (chemical properties) were collected at the type location and analyzed at the Oregon State University soil-testing laboratory.

Soil classified using the 12th Edition of the Keys to Soil Taxonomy.

NASIS User Pedon ID:82CA605REDW009

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National Cooperative Soil Survey
U.S.A.