LOCATION GUNWALE CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, isomesic Ultic Haploxeralfs
TYPICAL PEDON: Gunwale loam on a hill side under a cover of Bishop Pines at an elevation of 910 feet (277 meters). (Colors are for moist soil unless otherwise noted).
Oi--0 to 1 inch, (0 to 2 cm); slightly decomposed pine needles; abrupt smooth boundary. (1 to 5 inches thick, 2 to 13 centimeters)
Oe--1 to 2 inches, (2 to 4 cm); moderately decomposed pine needles; abrupt smooth boundary. (1 to 5 inches thick, 2 to 13 centimeters)
A--2 to 4 inches, (4 to 9 cm); brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; 19 percent clay; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; common fine roots and common medium roots and common coarse roots; 5 percent 2 to 75 millimeter gravel; very strongly acid (pH 5.2); clear wavy boundary. (1 to 5 inches thick, 2 to 13 centimeters)
Bw--4 to 11 inches, (9 to 28 cm); pale brown (10YR 6/3) sandy loam, brown (10YR 4/3) moist; 15 percent clay; moderate medium subangular blocky structure; slightly hard, very friable, nonsticky, slightly plastic; common fine roots and common medium roots and common coarse roots; 5 percent 2 to 75 millimeter gravel; very strongly acid (pH 5.0); clear wavy boundary. (4 to 10 inches thick, 10 to 25 centimeters)
Bt--11 to 22 inches, (28 to 55 cm); yellowish brown (10YR 5/4) sandy clay loam, dark yellowish brown (10YR 4/4) moist; 29 percent clay; strong coarse subangular blocky structure; hard, very friable, slightly sticky, slightly plastic; common fine roots and common medium roots and common coarse roots; continuous prominent clay films on all faces of peds; 5 percent 2 to 75 millimeter gravel; very strongly acid (pH 5.0); clear wavy boundary. (4 to 15 inches thick, 10 to 38 centimeters)
Cr--22 to 32 inches, (55 to 82 cm); soft, easily augered and excavated diorite with 90 percent rock structure.
TYPE LOCATION: Santa Cruz Island, Santa Barbara County, CA, in the Channel Islands Soil Survey Area 34 degrees North latitude, 0 minutes, 6 seconds and 119 degrees, 49 minutes, 2 seconds West longitude, NAD83; U.S.G.S Quad: Santa Cruz Island.
RANGE IN CHARACTERISTICS:
The mean annual soil temperature is 54 to 59 degrees F. (12 to 15 degrees C.) The difference in soil temperature between mean summer and mean winter is less than 6 degrees C. The soil moisture control section is dry in all parts from about mid-September to mid-November (about 90 days) and is usually moist the rest of the time.
Depth to bedrock is 20 to 40 inches (50 to 100 centimeters).
The particle size control section averages 18 to 35 percent clay and 0 to 15 percent rock fragments.
Base saturation by sum of bases is less than 75 percent throughout.
The A horizon dry color is 10YR 5/2, 5/3, 4/2, 4/3, 3/3, or 3/2. Moist color is 10YR 4/2, 4/3, 3/3, 3/2, or 2/2.
The Bw horizon dry color is 10YR 6/3 or 5/4. Moist color is 10YR 4/3 or 4/4.
The Bt horizon dry color is 10YR 6/3 or 5/4. Moist color is 10YR 4/3 or 4/4.
COMPETING SERIES: There are no competing soils in this family.
GEOGRAPHIC SETTING: Gunwale soils are on side slopes of mountains and hills on islands. Slopes range from 30 to 75 percent. The soils formed in colluvium and residuum from diorite. Elevations are 700 to 1200 feet (213 to 366 meters). The climate is characterized by warm, dry summers and cool, moist winters with fog common all year. The mean annual precipitation is 13 to 24 inches (330 to 610 mm), the mean annual temperature is 56 to 61 degrees F. (13 to 16 degrees C.), and the frost free season is 320 to 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Livigne and Macool soils. Livigne soils are shallow to bedrock and have mollic epipedons. Macool soils have fine particle size families and have mollic epipedons. Both these soils are on hills.
DRAINAGE AND PERMEABILITY: Well drained; very high runoff; moderately slow permeability.
USE AND VEGETATION: Wildlife habitat, recreation and building site development. Vegetation is Bishop Pines.
DISTRIBUTION AND EXTENT: Santa Barbara County, California on Santa Cruz Island. The soil is not extensive. MLRA 20.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Los Angeles County, California, 2004.
REMARKS: The series name is coined. Isomesic is indicated from data gathered from NRCS Soil Temperature/Soil Moisture climate stations. Ultic subgroup is determined from laboratory data from immediately adjacent pedons. Diagnostic horizons and features recognized in this pedon:
Ochric epipedon--The zone from the soil surface to a depth of about 4 inches.
Cambic horizon--The zone from a depth of 4 inches to a depth of about 11 inches.
Argillic horizon--The zone from a depth of 11 inches to a depth of about 22 inches.
Paralithic material--The zone from a depth of 22 inches to about 32 inches.