LOCATION ZYNBAR WAEstablished Series
TAXONOMIC CLASS: Medial, amorphic, frigid Typic Hapludands
TYPICAL PEDON: Zynbar gravelly silt loam - forested; on a 55 percent slope at 2,200 feet elevation in a 95 year old Douglas fir stand. (Colors are for moist soil unless otherwise stated.)
Oi--2 inches to 0; slightly decomposed liter. (1 to 4 inches thick)
Ac--0 to 6 inches; very dark grayish brown (10YR 3/2) gravelly silt loam, dark brown (10YR 4/3) dry; strong coarse and medium granular structure; slightly hard, very friable, nonsticky and nonplastic, weakly smeary; many very fine, fine, medium and coarse roots; many very fine and fine irregular pores; 20 percent shot-like aggregates; 25 percent gravel; neutral (pH 6.8); clear wavy boundary. (2 to 8 inches thick)
A--6 to 13 inches; dark brown (10YR 4/3) gravelly silt loam, light yellowish brown (10YR 6/4) dry; moderate medium, fine and very fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic, weakly smeary; many very fine, fine, medium and coarse roots; many very fine and fine irregular pores; 10 percent shot-like aggregates; 20 percent gravel; slightly acid (pH 6.4); clear wavy boundary. (4 to 10 inches thick)
Bwl--13 to 45 inches; dark yellowish brown (10YR 4/4) gravelly silt loam, very pale brown (10YR 7/4) dry; weak coarse, medium and fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic, weakly smeary; many very fine, fine and medium roots; many very fine and fine irregular pores; 20 percent gravel; slightly acid (pH 6.4); clear wavy boundary.
Bw2--45 to 60 inches; yellowish brown (10YR 5/6) silt loam, yellow (10YR 7/6) dry; weak coarse and medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic, weakly smeary; common very fine, fine and medium roots; many very fine and fine irregular pores; 10 percent gravel, moderately acid (pH 5.6). (Combined thickness of the Bw horizon is 30 to 50 inches.)
TYPE LOCATION: Lewis County, Washington; six miles north of Morton, Washington; about 1,700 feet north and about 600 feet west of the southeast corner of section 6, T. 13 N., R. 5 E.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 40 to more than 60 inches. The average annual soil temperature at a depth of 20 inches ranges from 40 to 46 degrees F. The particle-size control section is dominantly gravelly silt loam and contains 15 to 35 percent coarse fragments by volume. Moist and dry hue is 7.5YR or 10YR.
The Ac and A horizons have value of 2 through 4 moist, 4 through 6 dry and chroma of 2 through 6 dry and moist. They have weak or moderate subangular blocky structure. They are neutral to strongly acid.
The Bw horizon has hue of 5YR through 10YR, value of 3 through 5 moist, 5 through 7 dry and chroma of 3 through 6 dry and moist. It is loam, silt loam or gravelly silt loam. Some pedons have a C horizon similar to the Bw horizon. Below 40 inches some pedons have very gravelly silt loam, very gravelly loam or extremely stony silt loam C horizons. Reaction is neutral to moderately acid.
COMPETING SERIES: There are no competing series. Similar soils in other families are the Rugles and Tolany series. Rugles and Tolany soils are 0 to 10 percent rock fragments in the particle-size control section.
GEOGRAPHIC SETTING: The Zynbar soils are on mountain slopes having slope gradients of 0 to 65 percent. Elevations are 1,600 to 3,000 feet. The soils formed in material high in volcanic ash and basic igneous colluvium. The climate is marine with average annual precipitation of 70 to 100 inches consisting mainly of heavy winter rains and snowfall. Average annual temperature is 44 degrees F.; average January temperature is 30 degrees F.; and average July temperature is 60 degrees F. The growing season (28 degrees F.) is 100 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bromo, Cinebar, Cispus, Cotteral and Newaukum soils. Bromo, Cispus and Cotteral soils are pumiceous or ashy-pumiceous in the upper control section. Also, Cispus soils have a mesic soil temperature and Cotteral soils are cryic. Cinebar and Newaukum soils have an umbric epipedon and have a mesic soil temperature regime.
DRAINAGE AND PERMEABILITY: Well drained; medium or slow runoff; moderate permeability.
USE AND VEGETATION: Timber production, watershed and wildlife habitat are the main uses. Native Vegetation is Douglas-fir, noble fir, western hemlock and scattered western redcedar, bigleaf maple, red alder, and willow with an understory of western brackenfern, western swordfern, vine maple, Oregongrape, red huckleberry, trailing blackberry, Oregon oxalis, salal, salmonberry, longtube twinflower, Pacific trillium, violet, devilsclub and bedstraw.
DISTRIBUTION AND EXTENT: Southwestern Washington on the western side of the Cascade Mountain Range. Zynbar soils are of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Lewis County, Washington, 1976.
REMARKS: Classification only updated 7/98. This description reflects a change in classification based on the 1998 Keys to Taxonomy. Diagnostic horizons and features recognized in this pedon are an ochric epipedon from the mineral surface to 13 inches and a cambic horizon from 13 to 60 inches. The particle-size control section has an estimated moist bulk density of less than 0.90 g/cc, volcanic glass content of 30 to 60 percent, and ammonium-oxalate extractable aluminum plus one-half iron of more than 1 percent, and 15-bar water (dry) is greater than 15 percent.