LOCATION BUNCH              WA
Established Series
Rev. RGC/TDT
06/2000

BUNCH SERIES


The Bunch series consists of deep and very deep to hard bedrock, well drained soils that formed in colluvium from sedimentary and metasedimentary rocks on mountain slopes. Slopes are 50 to 100 percent. The average annual precipitation is about 150 inches and average annual temperature is about 42 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, isotic, isofrigid Typic Haplorthods

TYPICAL PEDON: Bunch loam-forestland, on a 68 percent southerly aspect at an elevation of 2,780 feet in a Pacific silver fir/Alaska huckleberry plant association. (When described on August 21, 1997, the soil was dry to 4.5 inches, and moist from 4.5 to 42 inches. Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)

Oi--0 to 2 inches; slightly decomposed needles, leaves, twigs, and cone fragments; abrupt smooth boundary. (0.5 to 2 inches thick)

Oa--2 to 4 inches; highly decomposed organic materials; abrupt smooth boundary. (0.5 to 4 inches thick)

E--4 to 8 inches; pale brown (10YR 6/3) loam, very pale brown (10YR 8/2) dry; weak very fine, fine, and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, medium, and coarse roots; common very fine and fine tubular and irregular pores; 10 percent gravelly; extremely acid (pH 3.6); abrupt wavy boundary. (1 to 9 inches thick)

Bhs1--8 to 19 inches; 80 percent strong brown (7.5YR 4/6) gravelly silty clay loam, yellow (10YR 7/6) dry and 20 percent dark brown (7.5YR 3/2), brown (7.5YR 5/3) dry; weak very fine, fine, and medium subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; weakly smeary; many very fine, fine, medium, and coarse roots; many very fine and fine tubular and irregular pores; 25 percent gravel; extremely acid (pH 3.6); clear wavy boundary.

Bhs2--19 to 26 inches; 90 percent strong brown (7.5YR 5/6) very gravelly silty clay loam, yellow (10YR 7/6) dry and 10 percent dark brown (7.5YR 3/4), yellowish brown (10YR 5/4) dry; weak very fine, fine, and medium subangular blocky structure; slightly hard, friable, moderately sticky and slightly plastic; weakly smeary; common very fine, fine, and medium and few coarse roots; common very fine and fine tubular and irregular pores; 35 percent gravel; very strongly acid (pH 4.6); clear wavy boundary. (Combined thickness of the Bhs horizon is 5 to 18 inches)

Bh1--26 to 33 inches; 90 percent dark yellowish brown (10YR 3/6)very gravelly silt loam, yellow (10YR 7/6) dry and 10 percent dark brown (7.5YR 3/4), yellowish brown (10YR 5/4) dry; weak very fine, fine, and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; weakly smeary; common very fine, fine, medium, and coarse roots; common very fine and fine tubular and irregular pores; 40 percent gravel, 5 percent cobbles; very strongly acid (pH 4.6); clear wavy boundary.

Bh2--33 to 46 inches; 60 percent dark yellowish brown (10YR 4/6) very gravelly silt loam, yellow (10YR 7/6) dry and 40 percent dark brown (7.5YR 3/3), brown (10YR 5/3) dry; weak very fine, fine, and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; weakly smeary; few very fine, fine, and medium roots; few very fine and fine tubular and irregular pores; 35 percent gravel, 15 percent cobbles; very strongly acid (pH 4.6); abrupt wavy boundary. (Combined thickness of the Bh horizon is 20 to 46 inches.)

R--46 inches; hard metasedimentary rock.

TYPE LOCATION: Jefferson County, Washington, about 5.5 miles north-northwest of the Quinault River Ranger Station, about 635 feet east and 2,220 feet north of the southwest corner of Section 8, T. 24 N., R. 9 W. (Latitude 47 degrees, 34 minutes, 55 seconds N., Longitude 123 degrees, 51 minutes, 22 seconds W.)

RANGE IN CHARACTERISTICS: Mean annual soil temperature is 43 to 47 degrees F. The mean summer soil temperature is 47 to 50 degrees F. and the mean winter soil temperature is 40 to 45 degrees F. The difference between the mean winter and mean summer soil temperature is 5 to 9 degrees F. These soils are usually moist, and are dry for 0 to 30 consecutive days in the moisture control section; udic moisture regime. Depth to bedrock is 40 to greater than 60 inches. The solum to a depth of 20 to 40 inches has an estimated moist bulk density of 0.70 to 0.90 g/cc, acid-oxalate extractable aluminum plus one half of the acid-oxalate extractable iron of 1 to 2 percent, phosphate retention of 40 to 85 percent, and 15-bar water retention of 20 to 30 percent for air dried samples. Base saturation by ammonium acetate is less than 10 percent throughout the profile.

The E horizon (albic materials) has hue of 10YR or 7.5YR moist, value of 5 or 6 moist and 7 or 8 dry, and chroma of 2 or 3 moist and 1 through 3 dry. It has 1 to 3 percent organic matter NaF pH is 7.0 to 8.5. It has 5 to 15 meq/100g of extractable aluminum.

The Bhs horizon has hue of 7.5YR moist, 7.5YR or 10YR dry, value of 3 through 5 moist and 4 through 7 dry, and chroma of 2, 4, 6, or 8 moist and 3, 4, or 6 dry. It is gravelly silty clay loam, very gravelly silty clay loam, or very gravelly loam. Reaction is extremely acid or very strongly acid. It has 3 to 6 percent organic matter. NaF pH is 8.5 to 10. It has 5 to 15 meq/100g of extractable aluminum. It has 20 to 35 percent clay.

The Bh horizon has hue of 10YR, 7.5YR 5YR, or 2.5Y moist and 10YR, 7.5YR, or 2.5Y dry, value of 3 through 5 moist and 5 through 7 dry, and chroma of 2, 3, 4, 6, or 8 moist and 2, 3, 4, or 6 dry. It is very gravelly silt loam, very gravelly loam, or extremely gravelly loam. Reaction is extremely acid or very strongly acid. Moist bulk density of 0.90 to 1.20 g/cc. NaF pH is 8.5 to 10. It has 5 to 15 meq/100g of extractable aluminum. It has 20 to 27 percent clay.

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING: Bunch soils are on mountain slopes. Slopes are 50 to 100 percent. The soils formed in colluvium from sedimentary and metasedimentary rocks. Elevations are 1200 to 3000 feet. Average annual precipitation is 130 to 170 inches. Fog drip contributes to the effective precipitation totals. Average annual temperature is 41 to 43 degrees F. The frost-free season is 120 to 140 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hookbranch, Kestner, Knorr, Lunchcreek, Samsriver, Snahopish, and Solleks soils. Hookbranch soils are perudic, lack a spodic and albic horizon and are moderately deep. Kestner soils are on glacial valleys and are moderately deep to dense till. Knorr and Samsriver soils are on glaciated moderate relief mountain slopes and are both moderately deep. Lunchcreek soils lack a spodic and albic horizon and have a perudic soil moisture regime. Snahopish soils lack an albic and spodic horizon. Solleks soils lack spodic and albic horizons and are moderately deep.

DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.

USE AND VEGETATION: Timber production, wildlife habitat, recreation, and watershed. Native vegetation is western hemlock, Pacific silver fir, Alaska huckleberry, mosses, red huckleberry, deer fern, queencup beadlily, bunchberry dogwood, and five leaf bramble.

DISTRIBUTION AND EXTENT: Jefferson County, Washington; MLRA 1. Series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Jefferson County, Washington, 2000; Olympic National Forest.

REMARKS: Diagnostic horizons and features recognized in this pedon are the following:

Albic horizon - 4 to 8 inches (E horizon)
Spodic horizon - 8 to 26 inches (Bhs1 and Bhs2 horizons)
Cambic horizon - 26 to 46 inches
Lithic contact - 46 inches
PSCS - 10 to 40 inches (Bhs1, Bhs2, Bh1, and Bh2 horizons)
Estimates on andic soil property ranges are based on data from the associated Samsriver and Knorr series S98WA-031-001 and 002.

All depths to diagnostic horizons are measured from the top of the first mineral horizon.


National Cooperative Soil Survey
U.S.A.