LOCATION BUNKER WAEstablished Series
TAXONOMIC CLASS: Medial over clayey, ferrihydritic over parasesquic, mesic Typic Fulvudands
TYPICAL PEDON: Bunker loam - forested. (Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)
Oi--0 to .5 inch; slightly decomposed litter of fir needles, twigs and moss roots.
Oa--.5 to 1 inch; highly decomposed litter; dark red with many white mycelia.
A--1 to 11 inches; dark reddish brown (5YR 3/3) medial loam, reddish brown (5YR 4/3) dry; moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic and weakly smeary; many roots; 15 percent angular basalt pebbles; moderately acid (pH 5.9); clear wavy boundary. (10 to 14 inches thick)
BA--11 to 18 inches; dark reddish brown (5YR 3/4) medial gravelly clay loam reddish brown (5YR 4/4) dry; moderate medium and fine subangular blocky structure; hard, friable, moderately sticky and moderately plastic and weakly smeary; many roots; 30 percent angular basalt pebbles; few medium and fine shot-like concretions; moderately acid (pH 5.9); clear irregular boundary. (2 to 10 inches thick)
2Bw1--18 to 34 inches; dark reddish brown (5YR 3/4) gravelly clay loam, reddish brown (5YR 4/4) dry; moderate medium and fine subangular blocky structure; hard, firm, moderately sticky and moderately plastic and weakly smeary; common roots; many fine pores; 30 percent angular basalt pebbles; moderately acid (pH 5.8); gradual wavy boundary.
2Bw2--34 to 52 inches; reddish brown (5YR 4/4) clay loam, reddish brown (5YR 5/4) dry; moderate medium subangular blocky structure; slightly hard, firm, moderately sticky and moderately plastic and weakly smeary; many roots; many fine pores; 10 percent angular basalt pebbles; moderately acid (pH 6.0); clear irregular boundary. (Combined thickness of the 2Bw horizon is 20 to 36 inches)
2BC--52 to 61 inches; dark brown (7.5YR 3/4) clay loam, reddish brown (5YR 4/4) dry; weak medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic and weakly smeary; few roots; 10 percent angular basalt pebbles; moderately acid (pH 6.0); clear irregular boundary. (4 to 12 inches thick)
2R--61 inches; fractured basalt.
TYPE LOCATION: Lewis County, Washington; on logging road number 5 Weyerhaeuser Company McDonald Tree Farm; approximately 1,980 feet south, 1,980 feet west of the northeast corner sec. 11, T. 12 N., R. 5 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 47 degrees to 5l degrees F. The depth to fractured bedrock ranges from 40 to more than 60 inches. Rock fragments in the particle-size control section average l5 to 35 percent. The upper part of the 0 to 40 inch particle-size control section has an estimated moist bulk density of 0.85 to 1.0 g/cc, volcanic glass content of 5 to 20 percent, acid-oxalate extractable aluminum plus one-half iron of 1.0 to 2.0 percent, phosphate retention of 85 to 95 percent, and 15 bar water retention of 15 to 20 percent for air dried samples. Organic carbon is less than 4 percent in some part of the upper 2/3 of the particle-size control section. Reaction ranges from very strongly acid to moderately acid.
The A horizon has hue of 5YR or 7.5YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of l to 3 moist, 3 or 4 dry. It has 0 to l5 percent pebbles. It has 10 to 15 percent organic matter.
The 2B horizon has hue of 5YR through l0YR, value of 3 or 4 moist, 4 or 5 dry, and chroma of 3 or 4 moist, 4 through 6 dry. It ranges from loam, clay loam, silt loam or silty clay loam with l0 to 35 percent rock fragments. It has 1 to 10 percent organic matter decreasing to less than 7 percent below 20 inches.
COMPETING SERIES: These are the Boistfort and the similar Vesta soils. Boistfort, and Vesta soils have 0 to 15 percent basalt fragments in the particle-size control section. In addition, Vesta soils are isomesic.
GEOGRAPHIC SETTING: The Bunker soils are on metastable side slopes, footslopes, benches, ridgetops, and hillsides at elevations of 100 to 2,200 feet. Slopes are 1 to 90 percent. These soils formed in colluvium weathered from basalt. Winters are cool and moist and summers are warm and dry. The average annual temperature is about 50 F., average January temperature is about 38 F., and average July temperature is about 60 F. Annual precipitation ranges from 70 to 120 inches. The growing season (28 F.) is 180 to 240 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Astoria, Katula, Lytell, Swem, Murnen, Squally, and Zenker soils and the competing Boistfort soils. Astoria soils are clayey. Katula and Squally soils have more than 35 percent hard rock fragments in the particle-size control section. Lytell and Zenker soils are more than 35 percent weathered rock fragments in the particle-size control section. Murnen soils have frigid soil temperatures. Swem soils have grayish mottles in the particle size control section.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Forested. Bunker soils are used for timber production, watershed, wildlife habitat, and recreation. Vegetation is mainly a Douglas-fir and western hemlock with an understory of western swordfern, Oregon-grape, red huckleberry, and vine maple.
DISTRIBUTION AND EXTENT: Southwestern Washington. The soil is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wahkiakum County, Washington, l976.
REMARKS: Diagnostic horizon and features recognized in this pedon are an umbric epipedon from 1 to 11 inches and a cambic horizon from 11 to 61 inches. The upper 17 inches of the soil has andic soil properties. All depths to diagnostic horizons and features are measured from the top of the first mineral horizon.
ADDITIONAL DATA: The classification is based on laboratory data taken on the Boistfort series and are available at the National Soil Survey Laboratory, Lincoln, Nebraska: Sample S77WA25-2 and 84P-906. Partial data are available on the Bunker series laboratory number S76WA-27-1..