LOCATION KARU WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic Vitrixerandic Haplocryepts
TYPICAL PEDON: Karu stony ashy sandy loam, on a southeast-facing 40 percent slopes at an elevation of 5,320 feet in a Douglas-fir and subalpine fir forest. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)
Oe--0 to 1 inch; moderately decomposed needles, leaves, and twigs; abrupt smooth boundary. (1 to 2 inches thick)
A--1 to 5 inches; light brownish gray (10YR 6/2) stony ashy sandy loam, dark grayish brown (10YR 4/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine and few medium and coarse roots; common fine irregular pores; 5 percent angular pebbles, 3 percent angular cobbles and 5 percent stones; slightly acid (pH 6.4); clear smooth boundary. (1 to 5 inches thick)
Bw--5 to 17 inches; pale brown (10YR 6/3) cobbly ashy sandy loam, dark grayish brown (10YR 4/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine and few medium and coarse roots; common fine irregular pores; 10 percent angular pebbles and 10 percent angular cobbles; slightly acid (pH 6.4); clear wavy boundary. (6 to 15 inches thick)
2C1--17 to 23 inches; light brownish gray (10YR 6/2) very cobbly sandy loam, massive; soft, very friable, nonsticky and nonplastic; few very fine, fine and medium roots; common very fine and fine irregular pores; 20 percent angular pebbles, 20 percent angular cobbles, and 2 percent stones; slightly acid (pH 6.4); clear smooth boundary.
2C2--23 to 34 inches; light brownish gray (10YR 6/2) very cobbly sandy loam, massive; slightly hard, friable, nonsticky and nonplastic; few very fine roots; common very fine and fine irregular pores; 20 percent angular pebbles, 25 percent angular cobbles, and 2 percent stones; slightly acid (pH 6.4); clear wavy boundary. (combined thickness of the 2C horizon is 17 to 20 inches)
3C3--34 to 61 inches; light gray (10YR 7/2) very gravelly loamy sand, light brownish gray (10YR 6/2) moist; massive; loose; nonsticky and nonplastic; few very fine roots; 45 percent pebbles and 5 percent cobbles; slightly acid (pH 6.2).
TYPE LOCATION: Okanogan County, Washington, about 1 mile south of Bobcat Mountain; 2,200 feet east and 2,000 feet south of the northwest corner of section 13, T. 34 N., R. 23 E. (Latitude 48 degrees 26' 50" N., Longitude 119 degrees 53' 46" W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 37 to 43 degrees F. The average summer soil temperature ranges from 42 to 46 degrees F. These soils are usually moist but are dry in all parts of the moisture control section for 45 to 60 consecutive days following the summer solstice. The solum is 7 to 20 inches thick and has an estimated bulk density of 1.00 to 1.30 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 10 percent for air dried samples. The particle-size control section averages 35 to 65 percent rock fragments and 5 to 18 percent clay.
The A horizon has values of 5 or 6 dry, 3 to 5 moist, and chromas of 2 or 3 dry or moist.
The Bw horizon has chromas of 3 or 4 dry. It is cobbly ashy sandy loam or gravelly ashy sandy loam. It has 10 to 35 percent pebbles, 0 to 10 percent cobbles, and 0 to 2 percent stones.
The 2C horizons has values of 5 or 6 dry, 4 or 5 moist, and chromas of 2 or 3 dry or moist. It is very cobbly sandy loam or very gravelly sandy loam. It has 20 to 40 percent pebbles, 10 to 30 percent cobbles, and 0 to 5 percent stones.
The 3C3 horizon has hues of 10YR or 2.5Y, 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 very cobbly sandy loam. It has 25 to 45 percent pebbles and 0 to 20 percent cobbles.
COMPETING SERIES: These are the Judco, Karloff, Torpy, Verhart, Volmont, Wellsfar, and Winsand series. Verhart and Volmont soils have bedrock at 20 to 40 inches. Judco soils have a Cr horizon at 40 to 60 inches. Karloff and Wellsfar soils have a paralithic contact at 20 to 40 inches. Torpy soils have an ustic moisture regime and lack a 3C horizon formed in till. Winsand soils are 40 to 60 inches to bedrock.
GEOGRAPHIC SETTING: Karu soils are on backslopes of mountains usually with a southerly aspect. Elevation ranges from 5,000 to 5,800 feet. Slopes are 35 to 65 percent. These soils formed in colluvium over till from metaigneous rock with a component of volcanic ash in the upper part. The climate is characterized by cold, wet winters and cool, dry summers. Average annual precipitation ranges from 25 to 35 inches. The average January temperature ranges from 18 to 22 degrees F, average July temperature ranges from 52 to 58 degrees F, and the average annual air temperature ranges from 35 to 41 degrees F. The frost-free season is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Lekrem, Myerscreek, Newhorn, and Sitdown soils. Lekrem soils are on south facing backslopes and are frigid. Myerscreek soils are on footslopes and backslopes and have a volcanic ash mantle 7 to 14 inches thick. Newhorn soils are on footslopes, have a frigid temperature regime, and a volcanic ash mantle 7 to 14 inches thick. Sitdown soils are on terraces and toeslopes and have a volcanic ash mantle 7 to 14 inches thick.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; and moderately rapid permeability.
USE AND VEGETATION: Used for timber production, wildlife habitat, watershed, and recreation. Native vegetation is Douglas-fir, lodgepole pine, subalpine fir, with an understory of pinegrass, silky lupine, mountainlover, kinnikinnick, and whortleberry.
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 recognized in this pedon include:
Ochric epipedon - 1 to 5 inches (A horizon)
Cambic horizon - 5 to 17 inches (Bw horizon)
Vitrandic properties - 1 to 17 inches (A and Bw horizon)
PSCS - zone from 11 to 41 inches (part of Bw, 2C1, 2C2, and part of 3C horizon)
Depths to diagnostic horizons and features are measured from the to of the first mineral horizon.