LOCATION SHUKSAN WAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, ferrihydritic Andic Humicryods
TYPICAL PEDON: Shuksan gravelly silt loam - on a 10 percent southwest-facing slope under a young stand of Pacific silver fir and western hemlock at 3,200 feet elevation. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures)
Oi--9 to 7 inches; leaves, needles, twigs, and wood fragments.
Oa--7 inches to 0; decomposed forest litter; many very fine, fine, medium, and coarse roots.
E--0 to 2 inches; brown (7.5YR 5/2) fine sandy loam, pinkish gray (7.5YR 7/2) dry; moderate medium subangular blocky structure; hard, friable, nonsticky, nonplastic; many very fine, fine, medium, and coarse roots; many fine irregular and few very fine tubular pores; 10 percent pebbles; NaF pH 9.2; extremely acid (pH 4.0); abrupt smooth boundary. (2 to 4 inches thick)
Bhs1--2 to 4 inches; dark reddish brown (5YR 3/2) silt loam, dark reddish gray (5YR 4/2) dry; black (5YR 2/1) organic stains throughout 80 percent of the soil matrix, dark reddish brown (5YR 3/2) dry; moderate medium subangular blocky structure; slightly hard, friable, nonsticky, nonplastic, and weakly smeary; many fine and medium and common very fine and coarse roots; many fine irregular pores; 5 percent pebbles; NaF pH 9.5; extremely acid (pH 4.2); abrupt smooth boundary. (1 to 2 inches thick)
Bhs2--4 to 15 inches; strong brown (7.5YR 4/6) gravelly silt loam, strong brown (7.5YR 5/6) dry; dark reddish brown (5YR 3/2) organic stains throughout 50 percent of the soil matrix, dark reddish gray (5YR 4/2) dry; moderate medium subangular blocky structure; slightly hard, friable, nonsticky, nonplastic, and weakly smeary; few very fine and common fine and medium roots; many very fine irregular and few fine tubular pores; 25 percent pebbles and 5 percent cobbles; NaF pH 10.6; very strongly acid (pH 4.6); abrupt smooth boundary (3 to 12 inches thick)
Bs1--15 to 29 inches; dark brown (7.5YR 4/4) very gravelly loam, light brown (7.5YR 6/4) dry; dark reddish brown (5YR 3/2) organic stains throughout 40 percent of the soil matrix, dark reddish gray (5YR 4/2) dry; weak fine subangular blocky structure; slightly hard, friable, nonsticky, nonplastic, and weakly smeary; few fine roots; many fine irregular pores; 40 percent pebbles and 5 percent cobbles; NaF pH 11.0; very strongly acid (pH 4.8); clear smooth boundary. (4 to 15 inches thick)
Bs2--29 to 35 inches; dark yellowish brown (10YR 4/4) very gravelly loam, yellowish brown (10YR 5/4) dry; dark reddish brown (5YR 3/2) organic stains on ped faces, dark reddish gray (5YR 4/2) dry; massive; slightly hard, friable, nonsticky, nonplastic, and weakly smeary; few fine irregular pores; 40 percent pebbles; NaF pH 11.5; strongly acid (pH 5.4); abrupt wavy boundary. (4 to 12 inches thick)
2Cr--35 to 60 inches; light olive brown (2.5Y 5/4) dense compact glacial till that breaks to very gravelly sandy loam, pale yellow (2.5Y 7/4) dry; massive; slightly hard, firm nonsticky, nonplastic; 40 percent pebbles; NaF pH 10.0; strongly acid (pH 5.4).
TYPE LOCATION: Whatcom County, Washington; about 5 miles north of Glacier; 1,550 feet north and 100 feet east of the southwest corner of sec. 13, T. 40 N., R. 6 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 41 to 44 degrees F. Depth to a paralithic contact of compact glacial till is 20 to 40 inches. The weighted average of rock fragments in the control section ranges from 35 to 50 percent. The organic content is more than 6 percent throughout the solum.
The E horizon has hue of 5YR or 7.5YR, value of 4 or 5 moist, 6 or 7 dry, and chroma of 2 or 3 moist and dry.
The Bhs1 horizon has value of 2 through 3 moist and 3 or 4 dry, and chroma of 2 or 3 moist. Reaction is extremely acid or very strongly acid.
The Bhs2 horizon has hue of 5YR or 7.5YR, value of 5 or 6 dry, and chroma of 4 through 6 moist and 6 through 8 dry. Rock fragments range from 20 to 35 percent. It is gravelly loam or gravelly silt loam. Reaction is strongly acid or very strongly acid.
The Bs horizon has hue of 7.5YR or 10YR, value of 3 through 5 moist, 5 through 7 dry, and chroma of 4 through 6 moist and dry. It is very gravelly loam or very gravelly sandy loam. Reaction is very strongly acid or strongly acid.
The 2Cr horizon is dense glacial till that breaks to very gravelly loam or very gravelly sandy loam. It has hue of 10YR through 5Y, value of 4 or 5 moist, 6 or 7 dry, and chroma of 1 through 4 moist and dry. Consistence is hard or very hard when dry and firm or very firm when moist. Hard rock fragments range from 40 to 50 percent. Reaction is strongly acid or moderately acid.
COMPETING SERIES: These are the Deming, Hinker, Humskel, Saar, Stirrup, and Thader series. Deming and Stirrup soils are deep. Hinker, Humskel, and Thader soils are 20 to 40 inches deep to a lithic contact. Saar soils are very strongly acid or strongly acid throughout and have less than 6 percent organic carbon in parts of the solum, but is as high as 8 percent in the Bhs horizon.
GEOGRAPHIC SETTING: The Shuksan soils are on glacially modified mountain slopes and plateaus at elevations of 3,000 to 4,500 feet. Slopes are 5 to 80 percent. The soils formed in volcanic ash, loess, and glacial till, slope alluvium, and colluvium. Shuksan soils have cool, dry summers and cold, wet winters. The average annual precipitation ranges from 85 to 105 inches. Mean January temperature is about 28 degrees F; the mean July temperature is about 56 degrees F. The mean annual temperature is about 41 degrees F. The frost-free season is about 85 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gallup, Getchell, and Kindy soils and the competing Kulshan and Saar soils. Gallup soils are fine-loamy and deep. Getchell soils are fine-loamy. Kindy soils have less than 6 percent organic carbon in the solum.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow to medium runoff; moderate permeability to the dense glacial till and very slow through it. A perched water table is as high as 2 to 3 feet at times from December through May.
USE AND VEGETATION: Used for timber production, watershed, and wildlife habitat. Native vegetation is Pacific silver fir, mountain hemlock, western hemlock, and western redcedar, with an understory of tall blue huckleberry, red huckleberry, bunchberry dogwood, longtube twinflower, and deerfern.
DISTRIBUTION AND EXTENT: West slopes of the Cascade Mountains in Whatcom County, Washington. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Whatcom County, Washington, 1983.
Remarks: This draft reflects a change in classification from medial-skeletal Humic Cryorthods to loamy-skeletal, mixed Humic Cryorthods. Partial laboratory data are available on this series. NSSL #80T7265-7266. This pedon meets chemical criteria for a spodic horizon. Diagnostic horizons and features recognized in this pedon are an albic horizon from the mineral surface to 2 inches, a spodic horizon with more than 6 percent organic carbon throughout and a paralithic contact with dense glacial till at 35 inches.