LOCATION BUNNELL WATentative Series
TAXONOMIC CLASS: Fine-loamy, isotic, frigid Andic Dystroxerepts
TYPICAL PEDON: Bunnell gravelly ashy loam - forested. (Colors are for dry soil unless otherwise noted. All textures are apparent field textures.)
Oi--0 to 1 inch; needles, leaves and twigs.
Oe--1 to 2 inches; partially decomposed needles, leaves and twigs.
A1--2 to 6 inches; dark brown (7.5YR 4/2) gravelly ashy loam, very dark brown (7.5YR 2/2) moist; weak very fine granular structure; soft, very friable, slightly sticky, nonplastic, weakly smeary; many very fine roots; many very fine irregular and many very fine tubular pores; 20 percent fine pebbles; neutral (pH 6.8); clear smooth boundary. (3 to 6 inches thick)
A2--6 to 11 inches; dark brown (7.5YR 4/3) gravelly ashy loam, very dark brown (7.5YR 2/2) moist; weak fine granular structure; soft, very friable, slightly sticky, nonplastic, weakly smeary; many very fine and common fine roots; many very fine irregular and many very fine tubular pores; 15 percent fine pebbles; moderately acid (pH 6.0); clear smooth boundary. (4 to 7 inches thick)
AB--11 to 21 inches; dark brown (7.5YR 4/3) ashy loam, dark brown (7.5YR 3/2) moist; weak very fine subangular blocky structure; soft, friable, slightly sticky, nonplastic, weakly smeary; many very fine and common fine roots; many very fine irregular and many very fine tubular pores; 10 percent pebbles; moderately acid (pH 6.0); gradual smooth boundary. (8 to 14 inches thick)
Bw1--21 to 33 inches; brown (10YR 4/3) gravelly ashy loam, dark brown (7.5YR 3/3) moist; weak fine and very fine subangular blocky structure; soft, friable, slightly sticky, nonplastic, weakly smeary; common very fine, fine and medium roots; many very fine irregular and many very fine tubular pores; 15 percent pebbles; moderately acid (pH 6.0); clear smooth boundary. (9 to 17 inches thick)
Bw2--33 to 44 inches; yellowish brown (10YR 5/4) very cobbly ashy loam, dark brown (7.5YR 3/4) moist; weak very fine subangular blocky structure; slightly hard, friable, slightly sticky, nonplastic, weakly smeary; few fine roots; common very fine irregular and common very fine tubular pores; 25 percent pebbles and 15 percent cobbles; slightly acid (pH 6.2); gradual smooth boundary. (9 to 17 inches thick)
BC--44 to 62 inches; light yellowish brown (10YR 6/4) extremely gravelly ashy loam, dark yellowish brown (10YR 3/4) moist; weak very fine subangular blocky structure; slightly hard, friable, slightly sticky, nonplastic, weakly smeary; few very fine roots; common very fine irregular and few very fine tubular pores; 60 percent pebbles and 5 percent cobbles; slightly acid (pH 6.4).
TYPE LOCATION: Yakima County, Washington; about 6 miles northwest of Glenwood; 1,700 feet south and 600 feet east of the northwest corner of sec. 26, T. 7 N., R. 11 E.
RANGE IN CHARACTERISTICS: Mean annual soil temperature is 39 to 43 degrees F. The soil moisture control section is usually moist but is dry in all parts for 45 to 60 consecutive days following summer solstice. Thickness of the influence of volcanic ash is 60 inches or more. Rock fragments in the particle-size control section range from 10 to 25 percent in the upper part and from 20 to 55 in the lower part and average 15 to 35 percent. Rock fragments below 40 inches range from 40 to 80 percent. Moist chroma is 3 or less to a depth of 20 inches or more. Reaction is moderately acid or slightly acid throughout.
The A horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3 dry and moist.
The Bw horizon has hue of 7.5YR or 10YR, value of 4 through 6 dry, 2 or 3 moist, and chroma of 1 to 4 dry and moist. It is loam or gravelly loam in the upper part and gravelly loam, very cobbly loam or very gravelly loam in the lower part.
The BC horizon has hue of 10YR or 7.5YR, value of 5 to 7 dry, 3 to 5 moist and chroma of 3 or 4 moist and dry. It is very gravelly loam or extremely gravelly loam. Rock fragments range from 40 to 80 percent.
COMPETING SERIES: These are the Ahart, Bercumb, Glen, Mountadams, Mullig, Pinbit, Revit, Sugarbowl, and Timberhead series. Bercumb and Glen soils have an umbric epipedon less than 20 inches thick. Mullig soils are dry for 60 to 75 consecutive days. Mountadams soils are 10 to 50 percent saprolitic in the particle-size control section. Pinbit soils are dry for 75 to 90 consecutive days. Revit soils are 20 to 40 inches deep to a lithic contact. Sugarbowl soils are less than 15 percent rock fragments in the particle-size control section. Timberhead soils have a mean annual soil temperature of 45 to 47 degrees F.
GEOGRAPHIC SETTING: Bunnell soils are on mountain shoulders and back slopes at elevations of 3,500 to 4,200 feet. Slopes are 2 to 25 percent. The soils formed in volcanic ash mixed with residuum and colluvium from King Mountain basalt. The climate is characterized by cool, dry summers, and cold, wet winters with snow cover from November to early May. Average annual precipitation is 42 to 47 inches. Average January temperature is 20 degrees F.; average July temperature is 58 degrees F. Annual temperature is 38 to 42 degrees F. Frost-free season is 65 to 85 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Bercumb and Mullig soils and the Alfir and Kingtain soils. Alfir soils are cryic and medial-skeletal. Kingtain soils are medial-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderate permeability.
USE AND VEGETATION: Used mainly for timber production, summer grazing and wildlife habitat. Vegetation is mainly grand fir, ponderosa pine, lodgepole pine and western white pine with an understory of sedge and wintergreen.
DISTRIBUTION AND EXTENT: Mountains of southwestern Yakima County, Washington. The series is of small extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Yakima County, Washington, 1976.
REMARKS: Diagnostic horizons and features recognized in this pedon are an umbric epipedon from 2 to 33 inches and a cambic horizon from 33 to 62 inches. The bulk density is assumed to be between 0.85 and 0.95 g/cc from 14 to 33 inches of depth.
Classification changed 1/00 from medial, frigid Andic Xerumbrepts to fine-loamy, isotic, frigid Andic Dystroxerepts based on amendments to Soil Taxonomy.
Depths to diagnostic horizons and features are measured from the to of the first mineral horizon.