LOCATION JUANDEFUCA WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Andic Haploxerepts
TYPICAL PEDON: Juandefuca very gravelly medial sandy loam - forestland, on a 61 percent south-facing slope at an elevation of 2,585 feet in a western hemlock/Pacific rhododendron-salal plant association. (When described on May 15, 1992, the soil was moist throughout. Colors are for dry soil unless otherwise stated.)
Oi--0 to 2 inches; slightly decomposed needles, leaves, twigs, and bark fragments; abrupt wavy boundary. (1 to 2.5 inches thick)
A--2 to 8 inches; brown (10YR 5/3) very gravelly medial sandy loam, very dark grayish brown (10YR 3/6) moist; weak very fine and fine granular structure; soft, very friable, nonsticky and nonplastic; weakly smeary; many very fine and common fine, medium, and coarse roots; common very fine and fine irregular pores; 45 percent gravel, 5 percent cobbles; strongly acid (pH 5.4); clear smooth boundary. (5 to 8 inches thick)
Bw1--8 to 13 inches; light yellowish brown (10YR 6/4) extremely gravelly sandy loam, dark yellowish brown (10YR 3/4) moist; weak very fine subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and nonplastic; many very fine and common fine, medium, and coarse roots; common very fine and fine irregular pores; 60 percent gravel, 5 percent cobbles; moderately acid (pH 5.6); clear wavy boundary.
Bw2--13 to 20 inches; very pale brown (10YR 7/4) extremely gravelly sandy loam, dark yellowish brown (10YR 3/6) moist; weak very fine subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and nonplastic; common very fine, fine, medium, and coarse roots; common very fine irregular pores; 70 percent gravel, 5 percent cobbles; moderately acid (pH 5.6); clear wavy boundary. (Combined thickness of the Bw1 and Bw2 horizon is 7 to 17 inches thick.)
Bw3--20 to 40 inches; very pale brown (10YR 7/4) extremely gravelly sandy loam, dark yellowish brown (10YR 3/6) moist; weak very fine subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and nonplastic; common very fine, fine, medium, and coarse roots; common very fine irregular pores; 70 percent gravel, 10 percent cobbles; moderately acid (pH 5.8); clear wavy boundary.
BC--40 to 62 inches; brownish yellow (10YR 6/6) extremely gravelly sandy loam, dark yellowish brown (10YR 3/6) moist; weak very fine and fine subangular blocky and weak very fine and fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, medium, and coarse roots; common very fine irregular pores; 50 percent gravel, 25 percent cobbles; moderately acid (pH 5.8);clear wavy boundary.
TYPE LOCATION: Jefferson County, Washington, about 1 mile southwest of Devils Lake, about 1,460 feet east and 720 feet north of the southwest corner of section 35, T. 27 N., R. 2 W. (Latitude 47 degrees, 47 minutes, 00 seconds N., Longitude 122 degrees, 53 minutes, 59 seconds W.)
RANGE IN CHARACTERISTICS: Mean annual soil temperature is 45 to 47 degrees F. These soils are usually moist but are dry in all parts of the soil moisture control section for 45 to 60 consecutive days in the 4 months following the summer solstice. Depth to bedrock is greater than 60 inches. The particle-size control section has 60 to 90 percent rock fragments by volume and 8 to 20 percent clay. Base saturation by ammonium acetate is 70 to 90 percent throughout the profile. The upper part of the solum from a depth of 12 to 25 inches has acid oxalate aluminum plus one-half the iron of 1 to 2 percent and moist bulk density of 0.80 to 1.00 g/cc.
The A horizon has hue of 10YR or 7.5YR moist and chroma of 3 or 4 dry and 2 through 4 moist. It has 5 to 10 percent organic matter. Moist bulk density if 0.50 to 0.90 g/cc.
The Bw horizon has hue of 10YR or 7.5YR moist, value of 5 through 7 dry and 3 or 4 moist, and chroma of 4 or 6 dry and moist. It is extremely gravelly sandy loam, extremely cobbly sandy loam, or extremely gravelly loam. Reaction is moderately or slightly acid. Moist bulk density if 0.80 to 1.20 g/cc in the upper part and ranges to 1.80 g/cc in the lower part.
COMPETING SERIES: These are the Inkler and Tunnelcreek series. Tunnelcreek soils are 20 to 40 inches to bedrock. Inkler soils have a volcanic ash mantle that contains more than 30 percent glass.
GEOGRAPHIC SETTING: Juandefuca soils are on mountain slopes and have slopes of 60 to 90 percent. The soils formed in colluvium from marine basalt and associated volcanic rocks. Elevations are 2,100 to 3,100 feet. Average annual precipitation is 35 to 70 inches. Average annual temperature is 44 to 46 degrees F. The frost-free season is 160 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Graywolf, Halfoss, Maidenpeak, Pennycreek, Slidecamp, Station, and the competing Tunnelcreek soils. Graywolf soils are on low relief dissected uplands and have an argillic horizon. Halfoss and Tunnelcreek soils are on mountain slopes and are 20 to 40 inches to bedrock. Maidenpeak soils are on mountain slopes and have a udic moisture regime. Pennycreek and Station soils are on mountain slopes and are 4 to 10 inches to bedrock. Station soils are on mountain slopes and are 10 to 20 inches to bedrock. Slidecamp soils are on low relief dissected uplands and have an argillic horizon with less than 35 percent coarse fragments.
DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability.
USE AND VEGETATION: Timber production, wildlife habitat, recreation, and watershed. Native vegetation is Douglas-fir, western hemlock, western redcedar, Pacific rhododendron, salal, Oregon-grape, baldhip rose, and creambush oceanspray.
DISTRIBUTION AND EXTENT: Clallam and Jefferson Counties, Washington; MLRA 2. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Jefferson County, Washington, 2000; Olympic National Forest.
REMARKS: Diagnostic horizons and features recognized in this pedon are the following:
Ochric epipedon
Cambic horizon - 8 to 62 inches
PSCS - 12 to 42 inches
Xeric moisture regime
The zone from 2 to 20 inches has bulk density of 0.90 g/cc and aluminum plus one-half the iron of 1.2 percent.
All depths to diagnostic horizons and other features are measured from the top of the first mineral horizon.