LOCATION YELLCREEK WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Vitrandic Haploxerolls
TYPICAL PEDON: Yellcreek gravelly ashy sandy loam, on a west facing 65 percent slope at an elevation of 2,500 feet in a Dougals-fir and ponderosa pine forest. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)
Oe--0 to 1 inch; moderately decomposed needles and twigs; abrupt smooth boundary. (1 to 2 inches)
A1--1 to 6 inches; very dark grayish brown (10YR 3/2) gravelly ashy sandy loam, black (10YR 2/1) moist; weak fine and medium granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; common very fine and fine tubular pores; 30 percent angular pebbles; neutral (pH 6.6); clear wavy boundary.
A2--6 to 13 inches; grayish brown (10YR 5/2) very gravelly ashy sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, and common medium and coarse roots; common very fine and fine tubular pores; 40 percent angular pebbles; neutral (pH 6.8); gradual wavy boundary. (combined A horizon thickness is 7 to 15 inches)
Bw--13 to 26 inches; light brownish gray (10YR 6/2) very gravelly ashy sandy loam, dark grayish brown (10YR 4/2) moist; weak fine and medium subangular blocky structure; soft, very friable; nonsticky and nonplastic; many very fine and fine, and few medium and coarse roots; common fine irregular pores; 50 percent angular pebbles and 5 percent angular cobbles; neutral (pH 6.6); gradual wavy boundary. (10 to 13 inches thick)
2C1--26 to 36 inches; light brownish gray (10YR 6/2) extremely gravelly sandy loam, grayish brown (10YR 5/2) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine and fine roots; few fine irregular pores; 60 percent angular pebbles and 10 percent angular cobbles; slightly acid (pH 6.4); gradual wavy boundary.
2C2--36 to 61 inches; pinkish gray (7.5YR 6/2) extremely gravelly sandy loam, brown (7.5YR 5/2) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; few fine irregular pores; 70 percent angular pebbles and 10 percent angular cobbles; slightly acid (pH 6.4).
TYPE LOCATION: Okanogan County, Washington; about 2 miles south-southeast of Mazama, Wa., 2,200 feet east and 500 feet south of the northwest corner of section 5, T. 36 N., R. 19 E. (Latitude 48 degrees 38' 50" N., Longitude 120 degrees 30' 12" W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 42 to 46 degrees F. These soils are usually moist but are dry in all parts of the moisture control section for 60 to 75 consecutive days following the summer solstice. The mollic epipedon thickness is 7 to 15 inches. The upper 7 to 20 inches has an estimated moist bulk density of 1.00 to 1.20 g/cc, volcanic glass content of 5 to 20 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 12 percent for air dried samples. The particle-size control section has 50 to 80 percent rock fragments and 5 to 15 percent clay. Reaction is slightly acid to neutral throughout.
The A horizon has values of 3 to 5 dry, 2 or 3 moist, and chromas of 2 or 3 dry or moist.
The Bw horizon has chromas of 2 or 3 dry or moist. It has 30 to 50 percent angular and subangular pebbles and 0 to 10 percent angular and subangular cobbles
The 2C horizon has hues of 10YR and 7.5YR, values of 5 or 6 dry, 4 or 5 moist, and chromas of 2 or 3 dry or moist. It is very gravelly sandy loam, very cobbly sandy loam or extremely gravelly sandy loam. Total rock fragments range from 50 to 80 percent. It has 40 to 70 percent angular and subangular pebbles, 10 to 20 percent angular and subangular cobbles, and 0 to 5 percent angular stones.
COMPETING SERIES: These are the Bearspring, Cassal, Dogtown, Frint, Hogranch, Mineral, Peahke, Pelican, Scoap, Shalrock, Wellscreek soils. The Bearspring soils have 35 to 50 percent rock fragments in the particle-size control section. Cassal soils are moderately well drained and have a Cd horizon. Dogtown soils have loamy sand or sand C horizons. Frint, Mineral, Peahke, and Shalrock soils have bedrock at 20 to 40 inches. Hogranch soils are 40 to 60 inches to bedrock. Pelican soils are dry for 75 to 90 days after the summer solstice. Scoap soils have a mollic epipedon 20 to 30 inches thick and 35 to 50 percent rock fragments in the particle-size control section. Wellscreek soils have 18 to 30 percent clay in the particle-size control section.
GEOGRAPHIC SETTING: Yellcreek soils are on backslopes of mountains. Elevations range from 2,300 to 4,700 feet. Slopes are 35 to 65 percent. These soils formed in colluvium and some till from sedimentary and volcanic rock sources with a component of volcanic ash in the upper part. The climate is characterized by warm, dry summers and cool, moist winters. The average annual precipitation ranges from 20 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 40 to 44 degrees F. The frost-free season is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buckrock, Longort, Midpeak, and Thout soils. Buckrock soils are on open shoulders and ridges and are mesic. Longort soils are on backslopes usually with southerly aspects, and have a lighter-colored surface. Midpeak soils are on upper backslopes, shoulders and ridges, and are 20 to 40 inches to bedrock. Thout soils are on shoulders and ridges and have a lighter-colored surface.
DRAINAGE AND PERMEABILITY: Well drained, rapid runoff; moderately rapid permeability.
USE AND VEGETATION: Used for wildlife habitat, recreation, and watershed. Native vegetation is Dougals-fir and ponderosa pine with an understory of mountainlover, shinyleaf spirea, luina, pinegrass, Scouler willow, and whortleleaf snowberry.
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: Mollic epipedon - 0 to 12 inches (A1 and A2 horizon)
Cambic horizon - 12 to 25 inches (Bw horizon)
PSCS - zone from 10 to 40 inches (part of the A2, Bw, 2C1 and part of the 2C2 horizon)