LOCATION TRAHAM WAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, ferrihydritic, isomesic Typic Fulvudands
TYPICAL PEDON: Traham very gravelly medial loam, on a southeast facing slope of 72 percent under coniferous forest at 640 feet elevation. (Colors are for moist soil unless otherwise stated. All textures are apparent field textures. When described, the soil was nearly dry to 6 inches, moist below.)
Oi--0 to 1 inch; slightly decomposed accumulation of roots, needles, twigs, and rotten wood fragments; abrupt smooth boundary.
Oe--1 to 4 inches; moderately decomposed roots, needles and twigs.
A1--4 to 6 inches; dark brown (7.5YR 3/2) very gravelly medial loam, dark brown (7.5YR 4/4) dry; strong medium subangular blocky structure; soft, very friable, nonsticky, nonplastic and weakly smeary; common medium and many fine roots; many fine interstitial pores; 35 percent pebbles and 5 percent cobbles; strongly acid (pH 5.2); clear wavy boundary. (1 to 3 inches thick)
A2--6 to 15 inches; dark reddish brown (5YR 3/3) very gravelly medial loam, reddish brown (7.5YR 4/4) dry; strong fine and very fine subangular blocky structure; soft, very friable, nonsticky, slightly plastic and weakly smeary; common medium, fine and very fine, and few coarse roots; many very fine interstitial pores; 35 percent pebbles and 5 percent cobbles; moderately acid (pH 5.8); clear smooth boundary. (7 to 13 inches thick)
Bw1--15 to 30 inches; dark reddish brown (5YR 3/4) very gravelly medial clay loam, reddish brown (5YR 4/4) dry; moderate medium subangular blocky structure; slightly sticky, slightly plastic and weakly smeary; few coarse, medium and fine roots; many fine interstitial and few very fine tubular pores; 40 percent pebbles and 5 percent cobbles; moderately acid (pH 6.0); clear smooth boundary. (11 to 22 inches thick)
Bw2--30 to 35 inches; brown (7.5YR 4/4) very gravelly medial clay loam, strong brown (7.5YR 5/6) dry; moderate very fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic and weakly smeary; few very fine roots; few very fine tubular pores; 55 percent pebbles and 5 percent cobbles; moderately acid (pH 6.0); abrupt smooth boundary. (4 to 6 inches thick)
R--35 inches; fractured basalt; few very fine roots in fractures.
TYPE LOCATION: Pacific County, Washington; along logging road B-1500; 2,000 feet west, 1,500 feet north of SE corner section 29, T.15N., R.9W.
RANGE IN CHARACTERISTICS: Depth to fractured basalt ranges from 24 to 36 inches. The particle size control section has 35 to 60 percent rock fragments that are mostly pebble size. The mean annual soil temperature is estimated to range from 47 to 49 degrees F. The soil is strongly acid or moderately acid. The umbric epipedon is 10 to 15 inches thick. Organic carbon is more than 4 percent in the upper 2/3 of the control section.
The A horizon has hue of 5YR or 7.5YR, value of 2 or 3 moist and chroma of 2 or 3 moist. It has subangular blocky or granular structure.
The B horizon has hue of 5YR or 7.5YR, value of 3 or 4 moist, 4 or 5 dry, and chroma of 4 through 6 dry. It is gravelly medial clay loam or very gravelly medial silty clay loam and contains 40 to 55 percent gravel and 5 to 10 percent cobbles. It is medium to very fine subangular blocky structure.
COMPETING SERIES: These are the Aschoff, Hoodview, Katula, Klone, Snahopish, Sollecks, and Squally series. Aschoff, Hoodview, Klone, Snahopish, and Squally soils lack bedrock within 40 inches. Katula soils have 60 to 80 percent rock fragments which are mostly cobbles and have less than 4 percent organic carbon in the upper part of the control section. Solleks soils have 60 to 75 percent sandstone fragments and very cobbly or extremely gravelly loam or silt loam B2 horizon.
GEOGRAPHIC SETTING: Traham soils are on mountain slopes, ridge crests, and spur ridges at elevations between 100 and 1,800 feet. Slopes are 8 to 90 percent. These soils formed in colluvium and residuum from Eocene age basalt. The climate is characterized by cool, wet winters and relatively cool, dry summers. The annual precipitation is 80 to 120 inches. The mean annual temperature is about 47 degrees F. and the growing season (28 degrees F.) is 180 to 220 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ilwaco, Knappton, Lates, Lebam, Murnen, Narel, Palix, and Vesta soils. Ilwaco, Lebam, Nare, and Palix soils lack hard rock fragments. Knappton soils are medial and have basalt at a depth of 40 to 60 inches. Lates and Murnen soils have a frigid temperature. Vesta soils have less than 15 percent coarse fragments in the profile and are more than 60 inches deep in basalt.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff in uncleared areas; moderate permeability.
USE AND VEGETATION: These soils are used for growing western hemlock, Douglas fir, western red cedar with some true fir and Sitka spruce at the higher elevations, and an understory of salal, huckleberry, swordfern, brachenfern, and red huckleberry.
DISTRIBUTION AND EXTENT: Southwestern Washington; MLRA 1. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Pacific County, Washington, 1978.
REMARKS: Classification only changed 4/94 because of recent amendments to Soil Taxonomy. A proposal to eliminate the color from the Fulvudand criteria is being made.