LOCATION LITTLEJOHN WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Andic Dystroxerepts
TYPICAL PEDON: Littlejohn gravelly ashy sandy loam-forested. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)
Oi--0 to 1 inch; slightly decomposed forest litter and moss, abrupt smooth boundary. (0 to 3 inches thick)
Oa--1 to 2 inches; highly black (10YR 2/1) decomposed forest litter, abrupt smooth boundary. (1 to 2 inches thick)
A--2 to 13 inches; dark yellowish brown (10YR 3/4) gravelly ashy sandy loam (volcanic ash) dark yellowish brown (10YR 4/4) dry; weak medium subangular blocky structure; soft, very friable, slightly sticky, slightly plastic, weakly smeary; many very fine, fine, and common medium roots; 15 percent pebbles, 5 percent cobbles, 15 percent ash; moderately acid (pH 5.6); clear wavy boundary. (7 to 14 inches thick)
2Bw1--13 to 19 inches; dark yellowish brown (10YR 3/4) very gravelly loam, yellowish brown (10YR 5/4) dry; moderate medium subangular blocky structure; soft, friable, slightly sticky, slightly plastic, weakly smeary; many fine and common medium and coarse roots; 25 percent pebbles, 10 percent cobbles; moderately acid (pH 5.8); abrupt wavy boundary. (5 to 10 inches thick)
2Bw2--19 to 32 inches; olive brown (2.5Y 4/4) extremely gravelly loam, light yellowish brown (2.5Y 6/4) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine, few medium and coarse roots; 40 percent pebbles, 15 percent cobbles, 5 percent stones; moderately acid (pH 5.8); abrupt wavy boundary. (6 to 20 inches thick)
2R--32 inches; fractured andesite.
TYPE LOCATION: Snoqualmie Pass Area, Pierce County, Washington; 135 feet north and 800 feet east of the southwest corner of sec. 5, T. 18 N., R. 7 E.
RANGE IN CHARACTERISTICS: Depth to the lithic contact is 25 to 40 inches. These soils are usually moist, but are dry in the moisture control section for 45 to 60 consecutive days following summer solstice. The upper 7 to 14 inches of the soil contains more than 60 percent volcanic ash. The control section averages 35 to 60 percent rock fragments and 0 to 20 percent pumice. The mean annual soil temperature is 42 to 47 degrees F.
The A horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 4 or 5 dry, and chroma of 3 or 4 moist and dry. Subhorizon with value and chroma of 3 are less than 7 inches thick. The A horizon contains more than 60 percent volcanic ash. It is strongly acid or moderately acid. Some pedons have an E horizon 1 to 2 inches thick.
The 2Bw1 horizon has hue of 10YR or 2.5Y, value of 4 or 5 moist, 5 or 6 dry, and chroma of 3 or 4 moist and dry. It is gravelly loam or gravelly sandy loam, very gravelly loam or very gravelly sandy loam with 10 to 50 percent gravel, 5 to 10 percent cobbles and 10 to 35 percent volcanic ash.
The 2Bw2 horizon has hue of 10YR or 2.5Y, value of 4 or 5 moist, 5 or 6 dry. It is very gravelly loam, very gravelly sandy loam, extremely gravelly sandy loam or extremely gravelly loam modified by 35 to 60 percent pebbles and 10 to 20 percent cobbles.
COMPETING SERIES: These are the Bertolotti, Cliffdell, Deroux, Mountaineer, Pitcher, Pheeney, Roxer, Scotties and Umpa series. Bertolloti, Cliffdell, Roxer, and Scotties soils are over 40 inches deep to bedrock. The Deroux, Mountaineer, and Umpa soils are dry for 60 to 75 consecutive days. Pheeney soils have an umbric epipedon.
GEOGRAPHIC SETTING: Littlejohn soils are on mountain sideslopes and ridges at elevations of 1,700 to 2,800 feet. Slopes range from 8 to 90 percent. These soils formed in residuum and colluvium from basalt and andesite or breccia, and volcanic ash and pumice in the upper part. Mean January temperature is about 31 degrees F; the mean July temperature is about 60 degrees F; and the mean annual temperature is about 45 degrees F. The average annual precipitation ranges from 60 to 80 inches. The frost-free season is 150 to 175 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Dobbs, Haywire, Jonas, Pheeney, and Zynbar soils and the competing Pitcher soils. Dobbs soils have a paralithic contact at a depth of 20 to 40 inches. Haywire soils are cryic. Dobbs, Jonas and Pheeney soils have an umbric epipedon. Zynbar soils have a bulk density of less than 0.85 g/cc.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff, moderate permeability.
USE AND VEGETATION: Used for timber production, wildlife habitat and watershed. Vegetation is Douglas-fir, western hemlock, some noble fir and Pacific silver fir at higher elevations, with an understory of salal, Oregongrape, western swordfern, and mosses.
DISTRIBUTION AND EXTENT: West slopes of the Cascade Mountains in west- central Washington; MLRA 3. Series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Snoqualmie Pass Area, Pierce County, Washington 1986.
REMARKS: Diagnostic horizons and features recognized in this pedon are an ochric epipedon and a cambic horizon from 13 to 32 inches and a lithic contact at 32 inches. This series needs review for a udic soil moisture regime placement based on the vegetative indicator of western hemlock.