LOCATION WAHKEENA OREstablished Series
TAXONOMIC CLASS: Fragmental, mixed, mesic Pachic Hapludolls
TYPICAL PEDON: Wahkeena very cobbly clay loam, forested. (Colors are for moist soil unless otherwise noted.)
O1--1/2 inch to 1; loose litter of needles, leaves, twigs, cones, etc.
A1--0 to 5 inches; very dark brown (10YR 2/2) very cobbly clay loam, very dark grayish brown (10YR 3/2) crushed, and dark grayish brown (10YR 4/2) dry; strong very fine subangular blocky and very fine and fine granular structure; slightly hard, friable, sticky and plastic; many roots; many fine and very fine irregular and tubular pores; 20 percent pebbles and 20 percent cobbles; slightly acid (pH 6.5); clear wavy boundary. (3 to 10 inches thick)
B1--5 to 14 inches; dark brown (10YR 3/3) extremely cobbly clay loam, brown (10YR 4/3) dry; moderate very fine and fine subangular blocky structure; slightly hard, friable, sticky and plastic; many roots; many fine and very fine irregular and tubular pores; 30 percent pebbles and 30 percent cobbles; neutral (pH 6.9); clear wavy boundary. (4 to 12 inches thick)
B2--14 to 27 inches; dark brown (10YR 3/3) extremely cobbly clay loam, brown (10YR 4/3) dry; moderate very fine and fine subangular blocky structure; slightly hard, friable, sticky and plastic; common roots; many fine, very fine, medium, and coarse irregular and many very fine tubular pores; 35 percent pebbles, 40 percent cobbles, and 5 percent stones; neutral (pH 6.6); clear wavy boundary. (6 to 18 inches thick)
B3--27 to 60 inches; dark brown (10YR 3/3) extremely cobbly clay loam, brown (10YR 4/3) dry; some lenses of very dark brown (10YR 2/2) in the upper portions of this horizon; weak very fine and fine subangular blocky structure; slightly hard, friable, sticky and plastic; common roots; many fine and very fine, and few coarse irregular and many very fine tubular pores; 35 percent pebbles, 40 percent cobbles, and 5 percent stones; neutral (pH 6.7).
TYPE LOCATION: Multnomah County, Oregon; 200 feet west of the footbridge over Wahkeena Falls along the Wahkeena Trail; NE1/4 NE1/4 section 13, T.1N., R.5E., W.M.
RANGE IN CHARACTERISTICS: Profiles are usually moist and are dry between depths of 4 and 12 inches for 50 degrees to 56 degrees F. Solum thickness ranges from 24 to 60 inches. Depth to basaltic bedrock dominantly is more than 60 inches. Many interstices larger than 1 mm are not filled. Stone lines, consisting of angular pebbles, cobbles, and stones, with little or no fines, and common within these profiles. Base saturation is more than 50 percent throughout the profile. The mollic epipedon is 24 to 40 inches or more thick.
The A horizon has hue of 10YR or 7.5YR, value of 2 or 3 moist and chroma of 1 or 2 moist. It is loam or clay loam with 40 to 60 percent rock fragments.
The B and C horizons have hue of 10YR or 7.4YR, value of 3 or 4 moist and chroma of 3 or 4 moist. It is loam or clay loam with 60 to 90 percent rock fragments.
COMPETING SERIES: This is the Hoodview series. Hoodview soils are medial-skeletal and have an umbric epipedon.
GEOGRAPHIC SETTING: The Wahkeena soils ar on smooth and dissected mountain slopes of 60 to 90 percent, at elevations of 50 to 3,000 feet. The soils formed in colluvium weathered from the Columbia River Basalt formation. The climate is humid. The mean annual precipitation ranges from 60 to 100 inches falling as rain in the autumn, winter, and spring. Winter snows are usually light and ephermeral. Rainfall amounts are relatively low in the summer. Drying east winds are frequent. The average January temperature is 35 degrees F. The average July temperature is 68 degrees F. The average annual temperature is 48 degrees to 54 degrees F. The frost-free period is 100 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aschoff and Bull Run soils. Aschoff soils are medial-skeletal. Bull Run soils are deep silt loam soils lacking rock fragments above depth of 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid surface runoff; moderately rapid permeability.
USE AND VEGETATION: Wahkeena soils are used for recreation, wildlife and for timber production. The overstory vegetation is Douglas-fir, grand fir, bigleaf maple, red alder, and others. The understory vegetation dominantly is swordfern, vine maple, hazel, Indian plum, and a wide variety of other herbs and shrubs.
DISTRIBUTION AND EXTENT: The Cascade Mountains of northwestern Oregon. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Multnomah County, Oregon (Bull Run, Sandy Area), 1976.
ADDITIONAL DATA: Characterization data for one pedon (FS63-Ore-045-30) by Oregon State University (Unpublished).