LOCATION PITCHER WAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Andic Dystroxerepts
TYPICAL PEDON: Pitcher ashy sandy loam - under a coniferous forest on a 60 percent southwest facing convex slope at an elevation of 2,200 feet. The soil was moist when described. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)
Oi--0 to 0.5 inch; slightly decomposed leaves, needles, and twigs; abrupt smooth boundary. (1 to 2 inches thick)
Oa--0.5 to 1 inch; decomposed organic litter; abrupt smooth boundary. (0 to 2 inches thick)
A--1 to 9 inches; brown (10YR 4/3) ashy sandy loam (volcanic ash and cinders), pale brown (10YR 6/3) dry; single grain; loose, weakly smeary; common very fine, fine, medium, and coarse roots; 10 percent pebbles and 5 percent weathered hard cinders; moderately acid (pH 6.0); clear smooth boundary. (7 to 14 inches thick)
2Bw1--9 to 17 inches; brown (10YR 4/3) gravelly sandy loam, light yellowish brown (10YR 6/4) dry; single grain; loose, weakly smeary; common very fine, fine, medium, and coarse roots; 15 percent pebbles and 10 percent weathered hard cinders; slightly acid (pH 6.2); clear smooth boundary. (6 to 10 inches thick)
2Bw2--17 to 25 inches; matrix is brown (10YR 4/3) very gravelly loam, light yellowish brown (10YR 6/4) dry, weathered hard cinders and pebbles in matrix are brown (7.5YR 4/4); weak fine subangular blocky structure; soft, friable, slightly sticky and slightly plastic, weakly smeary; common very fine, fine, and few medium roots; 40 percent pebbles, 15 percent weathered hard cinders, and 1 percent cobbles; slightly acid (pH 6.2); clear smooth boundary. (6 to 12 inches thick)
2Bw3--25 to 30 inches; brown (10YR 4/3) very gravelly loam, light yellowish brown (10YR 6/4) dry; moderate fine subangular structure; soft, friable, slightly sticky and slightly plastic, weakly smeary; common very fine and few fine roots; 10 percent weathered hard cinders, 45 percent pebbles, and 1 percent cobbles; moderately acid (pH 5.9); gradual smooth boundary. (0 to 10 inches thick)
2BC1--30 to 39 inches; brown (10YR 4/3) very gravelly loam, very pale brown (10YR 7/3) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic, weakly smeary; few very fine and fine roots; 50 percent pebbles and 5 percent cobbles; moderately acid (pH 6.0); gradual smooth boundary. (8 to 16 inches thick)
2BC2--39 to 61 inches; yellowish brown (10YR 5/4) very gravelly loam, very pale brown (10YR 7/3) dry; moderate medium subangular structure; slightly hard, friable, slightly sticky and slightly plastic, weakly smeary; few very fine roots; 50 percent pebbles and 5 percent cobbles; slightly acid (pH 6.2).
TYPE LOCATION: Snoqualmie Pass Area, King County, Washington; about 2 miles east of Crystal Village; 2,200 feet south and 300 feet east of the NW corner of sec. 20, T. 19 N., R. 10 E.
RANGE IN CHARACTERISTICS: 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 these soils are more than 60 percent volcanic ash and pumice. The particle-size control section averages 35 to 60 percent rock fragments by volume. Mean annual soil temperature ranges from 44 to 47 degrees F.
The A horizon has hue of 7.5YR or 10YR, value of 2 through 4 moist, 5 or 6 dry, and chroma of 2 through 4 moist or dry. It is strongly acid or moderately acid. Some pedons have weakly developed E horizons.
The 2Bw horizon has hue of 7.5YR or 10YR, value of 4 or 5 moist, 5 or 6 dry, and chroma of 3 or 4 moist. It is sandy loam or loam modified by 0 to 20 percent weathered hard cinders, 10 to 45 percent pebbles, and 0 to 15 percent cobbles. It is weakly to moderately smeary throughout. It is strongly acid through slightly acid.
The 2BC horizon has hue of 2.5Y, 10YR, or 7.5YR, value of 4 or 5 moist, 6 or 7 dry, and chroma of 3 through 6 moist or dry. It is very gravelly sandy loam, very gravelly loam, extremely cobbly sandy loam, or extremely cobbly loam and contains 30 to 50 percent pebbles and 5 to 40 percent cobbles. It is moderately acid or slightly acid.
COMPETING SERIES: These are the Bertolotti, Cliffdell, Deroux, Littlejohn, Mountaineer, Pheeney, Roxer, Scotties and Umpa series. Deroux, Littlejohn, Mountaineer, Pheeney and Umpa soils are 20 to 40 inches deep to a lithic contact. Pheeney soils have an umbric epipedon. Scotties soils are deep to a lithic contact and are dry 60 to 75 consecutive days. Bertolotti, Deroux, Mountaineer, Roxer and Umpa soils are dry for 60 to 75 consecutive days. Cliffdell soils are in a drier environment having 35 to 55 inches of precipitation.
GEOGRAPHIC SETTING: Pitcher soils are on colluvial sideslopes at elevations from 1,600 to 2,800 feet. The slopes are 8 to 90 percent. Pitcher soils formed in volcanic ash and cinders mixed with colluvium from a wide variety of extrusive igneous rocks. The climate is maritime with cool, dry summers and mild winters. The average annual precipitation ranges from 55 to 80 inches, occurring mostly as snowfall and rainfall during winter. Mean January temperature is about 31 degrees F, mean July temperature is about 60 degrees F, and the mean annual air temperature is about 44 degrees F. The frost-free season is 130 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Christoff, Ogarty, Playco, and Zynbar soils and the competing Littlejohn soils. Christoff soils have less than 35 percent coarse fragments in the control section. Ogarty soils have bedrock within 20 to 40 inches of the surface and are mesic. Playco soils are cryic. Zynbar soils are medial and have a bulk density of less than 0.85g/cc in the upper part of the control section.
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, and some noble fir, red alder, and Pacific silver fir at higher elevations. The understory is red alder, vine maple, western swordfern, salal, Oregongrape, western brackenfern, deer fern, red huckleberry, longtube twinflower, and trailing blackberry.
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, King County, Washington, 1986.
REMARKS: Diagnostic and horizons recognized in this pedon are an ochric epipedon and a cambic horizon. The series needs review for udic soil moisture regime based on vegetative indicators of western hemlock.