LOCATION HOOSIMBIM CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, active, mesic Ultic Haploxeralfs
TYPICAL PEDON: Hoosimbim extremely gravelly sandy loam--on a northeast facing concave slope of 54 percent under Douglas-fir, California black oak, California hazel, and poison-oak at an elevation of 2,690 feet. (Colors are for dry soil unless otherwise stated. When described on September 28, 1982, the soil was dry to 36 inches and slightly moist below that depth). The soil surface is covered by about 50 percent angular gravel.
Oi--2 to 0 inches; leaves, needles, and twigs more weathered with depth.
A--0 to 4 inches; yellowish brown (10YR 5/4) extremely gravelly sandy loam, dark yellowish brown (10YR 3/4) moist; strong very fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common medium and fine, many very fine roots; common fine and very fine tubular pores; 65 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (3 to 9 inches thick)
BA--4 to 10 inches; brown (7.5YR 5/4) very gravelly sandy clay loam, dark yellowish brown (7.5YR 4/4) moist; moderate fine and very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine and medium, few coarse roots; common fine and very fine tubular pores; 50 percent gravel; slightly acid (pH 6.5); gradual wavy boundary. (3 to 15 inches thick)
Bt1--10 to 16 inches; light brown (7.5YR 6/4) very gravelly sandy clay loam, strong brown (7.5YR 4/6) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine, few medium and coarse roots; few fine, common very fine tubular pores; few thin clay films lining pores and on ped faces; 55 percent gravel; slightly acid (pH 6.5); gradual wavy boundary. (5 to 9 inches thick)
Bt2--16 to 28 inches; reddish yellow (7.5YR 6/6) extremely gravelly sandy clay loam, strong brown (7.5YR 4/6) moist; moderate medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine, few medium and coarse roots; few fine, common very fine tubular pores; common thin clay films lining pores and on ped faces; 65 percent gravel; strongly acid (pH 5.5); gradual wavy boundary. (10 to 17 inches thick)
Bt3--28 to 42 inches; reddish yellow (7.5YR 6/6) extremely gravelly sandy clay loam, strong brown (7.5YR 4/6) moist; moderate medium and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and medium, common very fine roots; few fine, common very fine tubular pores; many thin clay films lining pores and on ped faces; 65 percent gravel, 5 percent cobbles; moderately acid (pH 6.0); abrupt wavy boundary. (10 to 16 inches thick)
R--42 inches; fractured metavolcanic rock. Fractures about 1 inch apart and about 1/8 inch wide. Clay films line fractures. Very fine roots line fractures.
TYPE LOCATION: Trinity County, California; 200 feet downhill from Highway 3, about 9.5 miles west of the intersection of Highways 3 and 299 at Douglas City; 1,250 feet east, 1,700 feet north of the southwest corner, section 22, T.32 N., R.10 W. Weaverville SW Quadrangle.
RANGE IN CHARACTERISTICS: Combined thickness of the A and Bt horizons and depth to bedrock ranges from 40 to 60 inches. The mean annual soil temperature ranges from 47 to 52 degrees F. The soil moisture control section is dry in all parts from mid July to mid October (about 90 to 100 days). The soil temperature at 20 inches exceeds 41 degrees F from about March 15 to December 31 (285 days), and exceeds 47 degrees F from April 20 to November 15.
The A horizon is 10YR 5/3, 5/4, 4/3, 7.5YR 5/4, or 4/6. Moist color is 10YR 3/4, 4/3, 3/2, or 7.5YR 3/2. It has 15 to 25 percent clay. The A horizon is neutral to moderately acid. The A horizon is less than 7 inches thick when colors meet mollic epipedon requirements.
The Bt horizon is 10YR 5/4, 6/6, 6/4, 7.5YR 7/6, 5/4, 6/4, 6/6, 5YR 4/6, 5/4, or 5/6. Moist color is 10YR 4/4, 5/6, 5/8, 7.5YR 4/4, 4/6, 5/8, 5YR 4/4, 4/6, or 3/4. It is extremely gravelly sandy clay loam, very gravelly clay loam, or very gravelly sandy clay loam. The Bt has 25 to 35 percent clay and 45 to 85 percent rock fragments. It is slightly acid to strongly acid.
COMPETING SERIES: These are the Abegg, Asabean (T), Behemotosh (T), Collayomi, Gasper (T), Hambone (T), Hollowtree, Holohan, Marpa, Pendola (T), Skalan, and Whispering series. The Abegg, Asabean, Collayomi, Holohan, and Pendola soils are greater than 60 inches deep, also the Collayomi soil is dominated by amorphous materials. The Abegg soils also have a MAST of 52 t 57. The Behemotosh, Hollowtree, Marpa, and Skalan soils have a lithic contact at 20 to 40 inches. The Gasper soils have less than 25 percent clay in the control section.
GEOGRAPHIC SETTING: The Hoosimbim soils are on mountains. Elevation is 1,550 to 4,750 feet. Slopes are 30 to 75 percent. These soils formed in residuum and colluvium from metavolcanic and some metasedimentary rocks. The climate is characterized by warm, dry summers and cool, moist winters. Mean annual precipitation is 35 to 65 inches. Snowfall ranges from 10 to 36 inches. Mean January temperature is about 35 degrees F, mean July temperature is about 68 degrees F, and the mean annual temperature is 45 to 57 degrees F. The frost-free period is 90 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dubakella, Marpa and Bamtush soils. Dubakella soils have lithic contact at 20 to 40 inches and have serpentinitic mineralogy. Bamtush soils are greater than 60 inches deep.
DRAINAGE AND PERMEABILITY: Well drained; rapid or very rapid runoff; moderate permeability.
USE AND VEGETATION: This soil is used for timber production, water supply and wildlife habitat. Vegetation consists of Douglas-fir, California black oak, California hazel, whitethorn ceanothus, ponderosa pine, and sugar pine.
DISTRIBUTION AND EXTENT: Klamath Mountains of northern California. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Trinity County, California; Weaverville Area, 1990. Soil name from Hoosimbim Mountain.
REMARKS: The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET
Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--zone from the surface to a depth of 10 inches (A, BA horizons)
Argillic horizon--the zone from 10 to 42 inches (Bt1, Bt2, Bt3).
Particle-size control section--the zone from 10 to 30 inches (Bt1, Bt2, Bt3).
Lithic contact--the boundary at 42 inches (R).