LOCATION BIRCHBAY WAEstablished Series
TAXONOMIC CLASS: Coarse-loamy over sandy or sandy-skeletal, isotic over mixed, mesic Typic Haplorthods
TYPICAL PEDON: Birchbay silt loam - on a 1 percent north-facing slope in pasture at 220 feet elevation. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)
Ap--0 to 8 inches; dark brown (10YR 3/3) silt loam, dark yellowish brown (10YR 4/4) dry; moderate medium granular structure; soft, very friable, nonsticky, nonplastic, weakly smeary; many very fine and fine roots; many very fine irregular pores; 2 percent pebbles; NaF pH 9.8; slightly acid (pH 6.2); abrupt smooth boundary. (4 to 10 inches thick)
Bs1--8 to 12 inches; dark brown (7.5YR 4/4) silt loam, strong brown (7.5YR 5/6) dry; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic, weakly smeary; common very fine and fine roots; many very fine irregular pores; 10 percent pebbles; NaF pH 10.5; medium acid (pH 5.8); clear smooth boundary.
Bs2--12 to 24 inches; dark yellowish brown (10YR 4/4) gravelly silt loam, brownish yellow (10YR 6/6) dry; weak medium subangular blocky structure; soft, very friable, nonsticky, nonplastic, weakly smeary; common very fine and fine roots; many very fine irregular pores; 20 percent pebbles: NaF pH 11.0; medium acid (pH 5.8); clear smooth boundary. (Combined thickness of the Bw horizon is 8 to 24 inches)
2C1--24 to 42 inches; dark yellowish brown (10YR 4/4) very gravelly sand, brownish yellow (10YR 6/6) dry; massive; slightly hard, very friable, nonsticky, nonplastic; very few fine roots; many fine irregular pores; 35 percent pebbles and 5 percent cobbles; NaF pH 11.0; medium acid (pH 5.6); clear wavy boundary. (8 to 22 inches thick)
3C2--42 to 60 inches; pale yellow (2.5Y 5/4) loam, light olive brown (2.5Y more than/4) dry; many large prominent mottles of strong brown (7.5YR 5/6), reddish yellow (7.5YR 6/6) dry; massive; very hard, firm, slightly sticky, slightly plastic; few fine irregular pores; 10 percent pebbles; medium acid (pH 5.8).
TYPE LOCATION: Whatcom County, Washington; about 5 miles west of Ferndale; 2,400 feet south and 1,600 feet east of the northwest corner of sec. 16, T. 39 N., R. 1 E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature is 50 to 54 degrees F. These soils are usually moist, but are dry for 60 to 75 consecutive days following the summer solstice. Thickness of volcanic ash influence and depth to the 2C horizon is 14 to 32 inches. Depth to the 3C horizon is 40 to 60 inches. By weighted average, the upper part of the particle-size control section has 5 to 25 percent pebbles, and the lower part has 35 to 50 percent pebbles and 0 to 5 percent cobbles. Reaction is medium acid or slightly acid throughout.
The A horizon has hue of 7.5YR or 10YR, value of 2 through 4 moist, 4 or 5 dry, and chroma of 2 through 4 moist, 3 or 4 dry. Some pedons have an E horizon
The Bs horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 5 or 6 dry, and chroma of 4 through 6 moist and dry. It is silt loam, loam, gravelly silt loam, or gravelly loam.
The 2C horizon has hue of 10YR or 2.5Y, value of 3 through 5 moist, 5 or 6 dry, and chroma of 2 through 4 moist, 2 through 6 dry. It is very gravelly loamy sand or very gravelly sand.
The 3C horizon has hue of 10YR through 5Y, value of 4 through 6 moist, 5 through 7 dry, and chroma of 2 through 4 moist and dry. Rock fragments average from 5 to 25 percent, although subhorizons contain up to 35 percent. It is loam, gravelly loam, clay loam, gravelly clay loam, or silty clay loam. Thin strata of sandy loam are in some pedons.
COMPETING SERIES: These are the Lystair and Winston series in the same family. Lystair soils are less than 15 percent rock fragments throughout the particle-size control section. Winston soils are dry for 45 to 60 consecutive days and are more than 35 percent rock fragments in the lower part of the particle-size control section.
GEOGRAPHIC SETTING: Birchbay soils are wave-reworked glaciomarine drift plains at elevations of 50 to 350 feet. The soils formed in volcanic ash and loess over glaciofluvial deposits and glaciomarine drift. Birchbay soils are in a marine climate with warm, dry summers and cool, moist winters. Snow cover is intermittent. Average annual precipitation is 30 to 40 inches, which falls mostly between October and May. Each of the summer months has at least one inch of rainfall. Mean January temperature is 36 degrees F; mean July temperature is 62 degrees F. The mean annual temperature is 50 degrees F. The frost-free season is 160 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Clipper, Hale, Kickerville, Labounty, Tromp, Whatcom, and Whitehorn soils. Clipper and Hale soils have mottles with a chroma of 2 or less within 15 cm below the spodic horizon. Hale soils have less than 35 percent rock fragments in the lower part of the control section. Kickerville soils are loamy-skeletal and well drained. Labounty and Whitehorn soils have an aquic moisture regime. In addition, Labounty soils are fine-loamy and Whitehorn soils are coarse-loamy. Tromp soils have grayish mottles within 30 inches of the surface and have less than 35 percent fock fragments in the lower part of the particle-size control section. Whatcom soils are fine-loamy.
DRAINAGE AND PERMEABILITY: Moderately well drained; very slow to medium runoff; moderate permeability in the solum, very rapid through the sandy upper substratum, and slow through the loamy lower substratum. A perched water table is at 2 to 4 feet from December through April.
USE AND VEGETATION: Used mainly for woodland and hay and pasture. It is also used for homesites and cropland. Native vegetation is Douglas-fir, red alder, western hemlock, western redcedar, grand fir, and paper birch, with an understory of vine maple, red huckleberry, salal, western swordfern, and Oregon-grape.
DISTRIBUTION AND EXTENT: Puget lowlands in northwestern Washington. The 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 over sandy or sandy-skeletal, mixed, mesic Andic Xerochrepts to coarse-loamy over sandy or sandy-skeletal, mixed, mesic Typic Haplorthods. Diagnostic horizons and features recognized in this pedon are an ochric epipedon from the surface to 8 inches, a spodic horizon from 8 to 24 inches, and a lithologic change to sandy-skeletal material at 24 inches. The spodic horizon does not meet chemical criteria for a spodic horizon, but does have micro morphological criteria, i.e. cracked coatings and silt-sized and larger pellets.