LOCATION PEBCREEK WAEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, isotic, frigid Vitrandic Haploxerepts
TYPICAL PEDON: Pebcreek ashy sandy loam, on a north facing 44 percent slope at an elevation of 4,300 feet in a Douglas-fir and lodgepole pine forest. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)
Oe--0 to 2 inches; moderately decomposed needles and twigs; clear smooth boundary. (1 to 3 inches thick)
A--2 to 7 inches; pale brown (10YR 6/3) ashy sandy loam, brown (10YR 4/3) moist; weak fine granular structure; soft, very friable, nonsticky, nonplastic and weakly smeary; many very fine and fine, and few medium and coarse roots; common very fine and fine irregular pores; 12 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (3 to 6 inches thick)
Bw--7 to 13 inches; light yellowish brown (10YR 6/4) gravelly ashy sandy loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky, nonplastic and weakly smeary; many very fine and fine, and few medium and coarse roots; common very fine and fine irregular pores; 15 percent gravel; slightly acid (pH 6.4); clear wavy boundary. (6 to 11 inches thick)
2C/B--13 to 39 inches; 70 percent very pale brown (10YR 7/3) and 30 percent light yellowish brown (10YR 6/4) very gravelly sand, 70 percent pale brown (10YR 6/3) and 30 percent dark yellowish brown (10YR 4/6) moist; single grain; loose; nonsticky and nonplastic; common very fine and fine roots; 40 percent gravel and 3 percent cobbles; slightly acid (pH 6.4); clear wavy boundary. (16 to 26 inches thick)
2C--39 to 44 inches; very pale brown (10YR 7/3) very gravelly loamy sand, pale brown (10YR 6/3) moist; single grain; loose; nonsticky and nonplastic; few very fine roots; 45 percent gravel; slightly acid (6.3); clear wavy boundary. (5 to 20 inches thick)
2Cd--44 to 62 inches; light gray (10YR 7/2) gravelly sandy loam, light brownish gray (10YR 6/2) moist; massive; very hard, friable, nonsticky and nonplastic; few very fine roots; few very fine irregular pores; 30 percent gravel and 2 percent cobbles; slightly acid (6.2).
TYPE LOCATION: Okanogan County, Washington; about 12 miles northeast of Winthrop, Wa., 1,500 feet east and 450 feet north of the southwest corner of section 5, T. 36 N., R. 22 E. (Latitude 48 degrees, 38 minutes, 37 seconds N., Longitude 120 degrees, 06 minutes, 51 seconds W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 39 to 46 degrees F. These soils are usually moist but are dry in all parts of the moisture control section 60 to 75 consecutive days following the summer solstice. The solum (A and Bw horizons) is 10 to 14 inches thick, has an estimated moist bulk density of 1.00 to 1.25 g/cc, volcanic glass content of 20 to 50 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 0.4 to 1.0 percent, and 15-bar water retention of 5 to 10 percent for air dried samples. The depth to the 2Cd horizon is 30 to 45 inches. The particle-size control section averages 35 to 65 percent rock fragments and 1 to 6 percent clay. Reaction is slightly acid to neutral.
The A horizon has values of 5 or 6 dry, 3 or 4 moist, and chromas of 2 or 3 dry or moist.
The Bw horizon has values of 3 or 4 moist and chromas of 2 to 4 dry or moist. It is gravelly ashy sandy loam, ashy sandy loam, or stony ashy sandy loam. It has 10 to 20 percent gravel, 0 to 5 cobbles and 0 to 10 percent stones.
The 2C/B horizon has values of 6 or 7 dry, 5 or 6 moist, and chromas of 3 or 4 dry or moist. It is very gravelly sand or very gravelly loamy sand. It has 35 to 45 percent gravel and 0 to 5 percent cobbles.
The 2C horizon has values of 6 or 7 dry, 5 or 6 moist, and chromas of 2 or 3 dry or moist. It is very gravelly loamy sand, very gravelly sand, or very gravelly loamy coarse sand. It has 30 to 45 percent gravel, 5 to 10 percent cobbles and 0 to 3 percent stones.
The 2Cd horizon has hues of 2.5Y or 10YR, values of 6 or 7 dry, 5 or 6 moist, and chromas of 2 or 3 dry or moist. It is very gravelly loamy sand, very gravelly sandy loam or gravelly sandy loam. It has 25 to 40 percent gravel, 0 to 10 percent cobbles and 0 to 3 percent stones.
COMPETING SERIES: This is the Wapal series. Wapal soils lack the densic contact..
GEOGRAPHIC SETTING: Pebcreek soils are on backslopes, footslopes, and terrace escarpments of mountains. Elevations range from 2,500 to 5,500 feet. Slopes are 15 to 65 percent. These soils formed in granitic glacial till and some glacial outwash with a mantle of volcanic ash in the upper part. The climate is characterized by warm, dry summers, and cool, moist winters. The average annual precipitation is 18 to 24 inches. The average January temperature ranges from 22 to 26 degrees F, the average July temperature ranges from 62 to 67 degrees F, and the average annual air temperature ranges from is 39 to 44 degrees F. The frost-free season is 85 to 125 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brevco, and the competing Wapal soils. Brevco soils are on shoulders and ridges and are 20 to 40 inches to granitic bedrock.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff; moderately rapid over slow permeability.
USE AND VEGETATION: Used for timber production, wildlife habitat, watershed, recreation and livestock grazing. Native vegetation is Douglas-fir, ponderosa pine and lodgepole pine with an understory of kinnikinnik, pinegrass, shinyleaf spirea, mountainlover, northwestern sedge, dwarf huckleberry, and blue huckleberry.
DISTRIBUTION AND EXTENT: Northcentral Washington. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Okanogan National Forest, Okanogan County, Washington, 2005.
REMARKS: Diagnostic horizons and features in this pedon include:
Ochric epipedon
Cambic horizon - 7 to 13 inches (Bw horizon)
PSCS - zone from 12 to 42 inches (part of Bw, 2C/B, and part of 2C horizon.) The zone from 12 to 13 inches is probably ashy and from 13 to 42 inches sandy-skeletal. The ashy part is not thick enough for strongly contrasting and thickest part is used.
Vitrandic properties from 2 to 13 inches
ADDITIONAL DATA: Lab data available for this soil. NSSL sampling numbers are 94P227 to 94P237.