LOCATION DEKAPEN WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, isotic, frigid Typic Haplorthods
TYPICAL PEDON: Dekapen loam, on a 16 percent slopes under a stand of Douglas-fir and western hemlock at 2,200 feet elevation. (Colors are for moist soil unless otherwise noted.)
01--1 to 1/4 inch; undecomposed needles, leaves, and twigs.
02--1/4 inch to 0; decomposed forest litter; many medium roots.
E--0 to 2 inches; dark brown (7.5YR 3/2) gravelly silt loam, pinkish gray (7.5YR 6/2) dry; weak fine subangular blocky structure; slightly hard, friable, nonsticky, nonplastic; many fine and medium roots; many fine irregular pores; 10 percent weathered pebbles and 15 percent hard pebbles; strongly acid (pH 5.1); abrupt wavy boundary. (1 to 3 inches thick)
Bhs--2 to 8 inches; dark brown (7.5YR 3/4) loam, light yellowish brown (10YR 6/4) dry; dark reddish brown (5YR 3/2) organic stains, dark brown (7.5YR 4/4) dry; weak, fine, and medium subangular blocky structure; slightly hard, firm, nonsticky, nonplastic, weakly smeary; many very fine and medium roots; common fine irregular pores; 40 percent weathered pebbles, 10 percent weathered cobbles and 5 percent hard pebbles; strongly acid (pH 5.4); clear wavy boundary. (6 to 8 inches thick)
Bs1--8 to 18 inches; yellowish brown (10YR 5/4) loam, very pale brown (10YR 7/4) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky, nonplastic, weakly smeary; many very fine and fine roots and few medium roots; many fine irregular pores; 25 percent weathered pebbles and 10 percent hard pebbles; strongly acid (pH 5.4); clear wavy boundary.
Bs2--18 to 24 inches; dark yellowish brown (10YR 3/4) loam, yellowish brown (10YR 5/4) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky, nonplastic, weakly smeary; many very fine and fine roots; many medium irregular pores and common medium tubular pores; 30 percent weathered pebbles and 5 percent hard pebbles; strongly acid (pH 5.4); clear smooth boundary. (Combined thickness of the Bs horizon is 13 to 17 inches.)
2C--24 to 31 inches; olive brown (2.5Y 4/4) loam, pale yellow (2.5Y 7/4) dry; common fine distinct mottles of dark brown (7.5YR 4/4), brown (7.5YR 5/4) dry; massive; weathered, friable, nonsticky nonplastic; common very fine and many fine medium irregular and common fine tubular pores; 30 percent weathered pebbles and 5 percent hard pebbles; strongly acid (pH 5.4); abrupt smooth boundary. (4 to 7 inches thick)
2Cr--31 to 60 inches; light olive brown (2.5Y 5/4) dense glacial till that breaks to loam, pale yellow (2.5Y 7/4) dry; common fine prominent mottles of strong brown (7.5YR 5/8), reddish yellow (7.5YR 6/8) dry; massive; very hard, very firm, nonsticky, nonplastic; few very fine irregular pores; 15 percent weathered pebbles and 5 percent hard pebbles; strongly acid (pH 5.4).
TYPE LOCATION: Whatcom County, Washington, about 2 miles southeast of Van Zandt, 1,700 feet north, and 2,400 feet west of the southeast corner, sec. 15, T. 38 N., R. 5 E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature ranges from 45 to 47 degrees F. Thickness of the solum and volcanic ash influence is 24 to 32 inches. Depth to a paralithic contact of dense compact glacial till is 24 to 40 inches. Content of rock fragments in the particle-size control section is 25 to 40 percent weathered pebbles, 0 to 15 percent weathered cobbles, and 5 to 15 percent hard pebbles by weighted average.
The E horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 5 to 7 dry, and chroma of 2 or 3 moist and dry.
The Bhs and Bs horizons have hue of 7.5YR or 10YR, value of 3 to 5 moist, 5 to 7 dry, and chroma of 4 to 6 moist and dry. They are loam or sandy loam.
The C horizon has hue of 10YR or 2.5Y, value of 4 or 5 moist, 6 or 7 dry, and chroma of 2 to 4 moist and dry. It is loam or sandy loam.
The 2Cr horizon is dense glacial till that breaks to loam or sandy loam. It has hue of 10YR or 2.5Y, value of 4 or 5 moist, 6 or 7 dry, and chroma of 2 to 4 moist and dry.
COMPETING SERIES: These are the Bangor, Becket, Berkshire, Chatham, Groveton, Houghtonville, Marlow, Michigamme, Mundal, Onota, Plaisted, Revel, Rawsonville, Rixon, Tunbridge, and Welcome series. Bangor, Becket, Berkshire, Chatham, Groveton, Houghtonville, Marlow, and Onota soils are more than 40 inches deep. Michigamme, Rawsonville, and Tunbridge soils have a lithic contact at 20 to 40 inches. Mundal and Onota soils have less than 25 percent weathered pebbles in the particle-size control section. Plaisted soils lack weathered rock fragments and have a fragipan. Revel soils have a paralithic contact with sandstone at 20 to 40 inches and lack a Bhs horizon. Rixon soils lack a Bhs horizon and have less than 25 percent weathered pebbles in the particle-size control section.
GEOGRAPHIC SETTING: Dekapen soils are on glacially modified mountain plateaus and backslopes at elevations of 1,600 to 2,200 feet. Slopes are 8 to 25 percent. The soils formed in volcanic ash, loess, and glacial till derived from sandstone. Dekapen soils are in a cool marine climate with cold, wet winters and cool, dry summers. Snow cover lasts from January through March. Average annual precipitation is 65 to 75 inches. Mean January temperature is about 32 degrees F, mean July temperature is about 59 degrees F, and the mean annual temperature is about 44 degrees F. The frost-free season is 110 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cupples and Welcome soils, and the competing Revel soils. Cupples soils are loamy-skeletal. Welcome soils are deep to a paralithic contact with sandstone.
DRAINAGE AND PERMEABILITY: Moderately well drained, slow runoff; moderate permeability to the dense glacial till and very slow through it. A perched water table is at a depth of 2 to 3 feet from December to April.
USE AND VEGETATION: Used for timber production. Native vegetation is western hemlock, Douglas-fir, western redcedar, red alder, and bigleaf maple, with an understory of western swordfern, red huckleberry, western brackenfern, vine maple, and northern twinflower.
DISTRIBUTION AND EXTENT: West slopes of the Cascade Mountains in Whatcom County. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Whatcom County, Washington, 1987.
REMARKS: Diagnostic horizons and features recognized in this pedon are: an albic horizon from the mineral surface to 2 inches; a spodic horizon from 2 to 24 inches; and a paralithic contact with dense glacial till at 31 inches.