LOCATION CEDARFLAT               CA

Established Series
Rev. JTB/JWH/ET
07/2016

CEDARFLAT SERIES

The Cedarflat series consists of very deep, well drained soils that formed in colluvium and residuum derived from serpentine. Cedarflat soils are on mountains and have slopes of 5 to 50 percent. The mean annual precipitation is about 1780 mm and the mean annual temperature is about 13 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, magnesic, thermic Pachic Haploxerolls

TYPICAL PEDON: Cedarflat gravelly loam on a northeast-facing slope of 40 percent under Idahoe fescue, California melicgrass, scattered Jeffrey pine and incense cedar, incense cedar seedlings, Indian's dream, and other grasses and forbs at an elevation of 720 meters. (Colors are for dry soil unless otherwise stated.) When described on 4/18/2007 the soil was moist throughout.

A1--0 to 20 cm; dark brown (7.5YR 3/3) gravelly loam, very dark brown (7.5YR 2/2) moist; weak very fine and fine granular structure; slightly hard, very friable, moderately sticky and slightly plastic; many very fine, few fine, and common medium roots throughout; few very fine, fine, and medium tubular pores; 10 percent gravel; slightly acid (pH 6.4); clear wavy boundary.

A2--20 to 50 cm; dark brown (7.5YR 3/3) gravelly loam, very dark brown (7.5YR 2/2) moist; weak very fine and fine granular structure; slightly hard, very friable, moderately sticky and slightly plastic; common very fine and fine, many medium, and common coarse roots throughout; few very fine, fine, and medium tubular pores; 25 percent gravel and 5 percent cobbles; neutral (pH 6.8); clear wavy boundary. (Combined thickness of the A horizon is 50 to 100 centimeters thick)

Bw--50 to 78 cm; yellowish brown (10YR 5/4) extremely cobbly loam, dark yellowish brown (10YR 3/4) moist; weak very fine and fine granular structure; moderately hard, friable, moderately sticky and moderately plastic; common very fine, few fine, and common medium, coarse, and very coarse roots throughout; few very fine, fine, and medium tubular pores; 10 percent gravel, 60 percent cobbles, 2 percent stones; 10 percent dark brown (7.5YR 3/3) prominent organic stains on all faces of peds; neutral (pH 6.8); clear wavy boundary. (Combined thickness of the Bw horizons is 10 to 50 centimeters thick)

Cd1--78 to 120 cm; light greenish gray (10GY 7/1) and gray (N 5/0) and olive gray (5Y 5/2) very cobbly sandy clay loam, greenish gray (10GY 5/1) and dark gray (N 4/0) and olive gray (5Y 4/2) moist; massive; very hard, firm, moderately sticky and moderately plastic; few very fine, fine, and medium roots around fragments; 5 percent faint clay films on rock fragments; 30 percent paragravel, 20 percent gravel, 15 percent cobbles, 5 percent stones; neutral (pH 6.8); gradual irregular boundary.

Cd2--120 to 200 cm; light greenish gray (10GY 7/1) and gray (N 5/0) very cobbly loam, dark gray (N 4/0) and greenish gray (10GY 5/1); massive; very hard, firm, slightly sticky and slightly plastic; 20 percent paragravel, 20 percent gravel, 25 percent cobbles, 10 percent stones; neutral (pH 6.8). (Combined thickness of the Cd horizons is 100 to 150 centimeters)

TYPE LOCATION: Humboldt County, California; about 12 kilometers southwest of the town of Miranda, CA; USGS Quadrangle Ettersberg, CA; 40 degrees 13 minutes 22 seconds north; WGS84 Decimal degrees 40.2227000 latitude and -123.9586472;-123 degrees 57 minutes 31 seconds west longitude UTM Zone 10 UTM 0418436mE, 4452916mN; NAD 83.

RANGE IN CHARACTERISTICS:

Soil moisture: The soil moisture control section, in normal years, is dry in all parts for 45 or more consecutive days in the 4 months following the summer solstice and moist in all parts for 45 or more consecutive days in the 4 months following the winter solstice. The soils have a xeric soil moisture regime.

Soil Temperature: The mean annual soil temperature at 50 centimeters is 15 to 16 degrees C and the difference between mean summer and mean winter soil temperature is 6 degrees or greater. The soils have a thermic soil temperature regime.

Depth to densic materials: 50 to 100 centimeters

Mollic epipedon: 50 to 100 centimeters thick

Particle size control section (weighted average):
Rock fragments: 35 to 75 percent
Pararock fragments: 0 to 34 percent
Clay content: 18 to 26 percent

A horizons:
Hue: 5YR, 7.5YR or 10YR
Value: 3 or 4, 2 or 3 moist
Chroma: 2 to 4, 2 or 3 moist
Clay content: 15 to 26 percent
Rock fragments: 15 to 59 percent indurated serpentinite gravel, 5 to 59 percent indurated serpentinite cobbles, and 0 to 14 percent indurated serpentinite stones
Reaction: slightly acid to neutral

Bw or Bt horizons:
Hue: 7.5YR or 10YR
Value: 5 or 6, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Clay content: 15 to 26 percent
Rock fragments: 15 to 59 percent indurated serpentinite gravel, 15 to 59 percent indurated serpentinite cobbles, and 0 to 14 percent indurated serpentinite stones
Pararock fragments: 0 to 34 percent very weakly cemented serpentinite gravel
Reaction: neutral to slightly alkaline

Cd horizons:
Hue: 2.5Y, 5Y, 10Y, 5GY, 10GY, 5BY, 5BG, N
Value: 3 to 8, 3 to 5 moist
Chroma: 0 to 4, dry or moist
Texture of fine earth: loam, sandy loam, sandy clay loam
Clay content: 5 to 26 percent
Rock fragments: 15 to 75 percent indurated serpentinite gravel, 15 to 59 percent indurated serpentinite cobbles, and 0 to 34 percent indurated serpentinite stones
Pararock fragments: 15 to 75 percent very weakly cemented serpentinite gravel
Reaction: neutral to slightly alkaline

COMPETING SERIES: This is the Bearvalley series. Bearvalley soils do not have densic materials within 190 centimeters.

GEOGRAPHIC SETTING: Cedarflat soils are on convex positions on mountain slopes and ridges. Slopes are 5 to 50 percent. Elevations are 300 to 900 meters. These soils formed in colluvium and residuum from serpentinite. The climate is subhumid with warm, dry summers and cool, wet winters. Mean annual precipitation is 1500 to 2030 millimeters. The mean annual temperature is 13 to 15 degrees C. Frost free season is about 240 to 280 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Salmonfalls (CA) and Yorknorth (CA) soils. Salmonfalls soils have less than 35 percent rock fragments in the particle size control section and are on convex positions. Yorknorth soils are not in the magnesic mineralogy class, have more than 35 percent clay in the particle size control section, and are on concave positions.

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

USE AND VEGETATION: This soil is used mainly for livestock grazing, wildlife habitat, recreation, and watershed. Natural vegetation includes Idahoe fescue, California melicgrass, scattered incense cedar and Jeffrey pine, prostrate ceanothus, Indian's dream, Tolmie star-tulip, creamcups, goldfields, blue dicks, and popcorn flower.

DISTRIBUTION AND EXTENT: Siskiyou-Trinity Area, MLRA 5. The series is not extensive.

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

SERIES ESTABLISHED: Humboldt County Soil Survey, Southern Part, California, 2010. The name is from Cedar Flat.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
1. Mollic epipedon: The zone from 0 to 50 centimeters (A1 and A2 horizons).
2. Densic materials: The zone from 50 to 200 (Cd1 and Cd2 horizons)
3. Particle size control section: The zone from 25 to 100 centimeters contain 20 percent clay, by weight, 9 percent paragravel, 20 percent gravel, 27 percent cobble, and 1 percent stones by volume(A2, Bw1, and Cd1 horizons)

ADDITIONAL DATA:

NASIS User Pedon ID: 07CA601843

Keys to Soil Taxonomy, 12th edition.

---

National Cooperative Soil Survey
U.S.A.