LOCATION PINECREEK IDEstablished Series
TAXONOMIC CLASS: Ashy over loamy-skeletal, glassy over isotic, frigid Humic Vitrixerands
TYPICAL PEDON: Pinecreek gravelly ashy silt loam, forest; on a southeast-facing convex slope of 38 percent at 4,000 feet elevation. When described on October 1, 1981, the soil was slightly moist to 20 inches and dry below. (Colors are for dry soil unless otherwise stated.)
Oi--0 to 1 inch; slightly decomposed grasses and leaves mixed with 1980 Mt. St. Helens volcanic ash.
A1--1 to 4 inches; grayish brown (10YR 5/2) gravelly ashy silt loam, very dark grayish brown (10YR 3/2) moist; weak very fine and fine granular structure; soft; very friable, nonsticky and slightly plastic; many very fine, fine, and common medium and coarse roots; many very fine, common fine, and few medium tubular and irregular pores; 15 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (2 to 5 inches thick)
A2--4 to 11 inches; brown (10YR 5/3) gravelly ashy silt loam, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure parting to weak fine and medium granular; soft, very friable, nonsticky and slightly plastic; many very fine, fine, and common medium and coarse roots; common very fine, fine, and few medium tubular and irregular pores; 15 percent gravel; slightly acid (pH 6.5); clear wavy boundary. (5 to 10 inches thick)
Bw1--11 to 23 inches; yellowish brown (10YR 5/4) gravelly ashy silt loam, dark yellowish brown (10YR 3/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and slightly plastic; common very fine, fine, medium, and few coarse roots; common very fine, fine, and few medium tubular and irregular pores; 20 percent gravel, 5 percent cobbles, and 5 percent stones; slightly acid (pH 6.3);clear wavy boundary. (7 to 12 inches thick)
2Bw2--23 to 38 inches; light yellowish brown (10YR 6/4) very gravelly silt loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine, medium, and few coarse roots; few very fine, fine, and medium tubular and irregular pores; 30 percent gravel, 10 percent cobbles, and 10 percent stones; slightly acid (pH 6.3); gradual wavy boundary. (6 to 15 inches thick)
2BC--38 to 51 inches; light yellowish brown (10YR 6/4) extremely cobbly silt loam, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, and few fine and medium roots; few very fine, fine, and medium tubular and irregular pores; 30 percent gravel, 30 percent cobbles, and 10 percent stones; slightly acid (pH 6.3); clear wavy boundary. (0 to 13 inches thick)
2C--51 to 60 inches; light yellowish brown (10YR 6/4) extremely cobbly silt loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine and fine tubular and irregular pores; 35 percent gravel, 40 percent cobbles, and 15 percent stones; slightly acid (pH 6.3).
TYPE LOCATION: Benewah County, Idaho; about 1.1 miles southwest of St. Joe Baldy; about 950 feet east and 850 feet north of the southwest corner of sec. 2, T. 46 N., R. 1 W. Latitude 47 degrees, 21 minutes, 28.7 seconds N., Longitude 116 degrees, 25 minutes, 55.7 seconds W.; NAD 83; USGS St. Joe Baldy quadrangle.
RANGE IN CHARACTERISTICS:
Soil moisture - usually dry for 45 to 60 consecutive days mid-July to mid September, moist in mid-September to mid-July
Average annual soil temperature - 45 to 47 degrees F
Average summer soil temperature - 49 to 58 degrees F with an O horizon
Depth to bedrock - greater than 60 inches
Solum thickness - 30 to 55 inches
Umbric epipedon thickness - 10 to 15 inches
Volcanic ash mantle - 14 to 22 inches thick
Volcanic glass content - 30 to 65 percent
Acid-oxalate extractable Al + 1/2 Fe - 1.0 to 3.0 percent
Phosphate retention - 55 to 90 percent
15 bar water retention on air dried samples - 7 to 12 percent
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 1 through 3 dry or moist
Texture GR-ASHY-SIL, ASHY-SIL
Clay content 3 to 8 percent
Base saturation - 15 to 25 percent
Rock fragments - 5 to 30 percent gravel
Bulk density - 0.65 to 0.85 g/cc
Reaction - slightly acid or neutral
Bw horizon
Value - 5 or 6 dry, 3 or 4 moist
Texture GR-ASHY-SIL, ASHY-SIL
Clay content 3 to 8 percent
Rock fragments 5 to 30 percent gravel, 0 to 10 percent channers, 5 to 30 percent total
Bulk density - 0.65 to 0.85 g/cc
Reaction - slightly acid or neutral
2Bw horizon
Hue - 10YR or 7.5YR
Value - 5 or 6 dry, 3 or 4 moist
Texture - GRV-SIL, CBV-SIL, CBV-L, GRX-L, GRX-SIL, GRV-L
Clay content 3 to 10 percent
Rock fragments 25 to 55 percent gravel, 0 to 30 percent cobbles, 40 to 60 percent total
Reaction - moderately acid to neutral
2C horizon
Hue - 10YR or 7.5YR
Value - 6 or 7 dry, 4 or 5 moist
Texture - CBX-SIL, STX-SIL, CBX-L, STX-L, GRX-L, GRX-SIL, FLX-L, CBX-SL, CBX-FSL
Clay content 3 to 10 percent
Rock fragments 20 to 60 percent gravel, 0 to 40 percent cobbles, 0 to 40 percent stones, 0 to 30 percent flagstones, 65 to 90 percent total
Reaction - strongly acid to slightly acid
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Pinecreek soils are on south and some north-facing mountain slopes at elevations of 2,200 to 4,800 feet. Slopes range from 35 to 75 percent. These soils formed in material weathered form metasedimentary rocks, with a thick mantle of volcanic ash. Average annual air temperature ranges from 44 to 46 degrees F, and average annual precipitation is 28 to 40 inches. The frost-free period is 90 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ahrs, Honeyjones, Hugus, Latour, Lotuspoint, and Tigley soils. The Ahrs soils are on east and west-facing mountain slopes, ashy-skeletal over loamy-skeletal,and have an ochric epipedon. Honeyjones soils are on north-facing mountain slopes and have an ochric epipedon. The Hugus and Tigley soils are on foothills and adjacent dissected terraces, and have argillic horizons. The Latour soils are on mountains at higher elevations and are cryic. The Lotuspoint soils are on south-facing ridges, have a mesic soil temperature regime, and have hard bedrock at 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: These soils are used for timber production, livestock grazing, wildlife habitat, recreation, and watershed. Potential natural vegetation is mainly Douglas-fir and ponderosa pine with an understory of mallow ninebark, common snowberry, pine reedgrass, creambush oceanspray, myrtle pachystima, rose, red-stem ceanothus, white spirea, and starry false-Solomons-seal. The moist phase in west Benewah County has a potential natural vegetation of grand fir, Douglas fir, and ponderosa pine with an understory of mallow ninebark, common snowberry, pine reedgrass, creambush oceanspray, myrtle pachystima, rose, thinleaf huckleberry, white spirea, elk sedge, and starry false-Solomons-seal.
DISTRIBUTION AND EXTENT: Northern Idaho. MLRA 43A. This soil is moderately extensive.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Benewah County, Idaho, 1983.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon - the zone from 1 to 11 inches (A1 and A2 horizons)
Cambic horizon - the zone from 11 to 38 inches (Bw1 and 2Bw2 horizons)
Volcanic ash mantle - the zone from 1 to 23 inches (A1, A2, Bw1 horizons)
Particle-size control section - the zone from 1 to 41 inches (A1, A2, Bw1, 2Bw2, and part of the 2BC horizon)
Classification revised 5/2005 from glassy over mixed mineralogy to glassy over isotic based on lab data and associated soils.
ADDITIONAL DATA: Partial laboratory data available for this pedon: SCS sample number 81-ID-009-6 and corresponding U of I lab sample number 81-ID-0556 from east Benewah County, ID, by the University of Idaho, Moscow ID.