LOCATION LATES WA+OREstablished Series
TAXONOMIC CLASS: Medial, ferrihydritic, frigid Typic Hapludands
TYPICAL PEDON: Lates silt loam - forested. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)
A1--0 to 5 inches; very dark brown (10YR 2/2) silt loam, dark brown (10YR 3/3) dry; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic and weakly smeary; common medium fine and very fine roots; many fine and very fine tubular pores; 2 percent gravel-size basalt fragments; very strongly acid (pH 4.6); abrupt wavy boundary. (4 to 7 inches thick)
A2--5 to 14 inches; black (10YR 2/l) silt loam, very dark grayish brown (10YR 3/2) dry; moderate medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic and weakly smeary; many fine and common coarse roots; common medium fine tubular pores; 5 percent gravel-size basalt fragments; very strongly acid (pH 4.8) abrupt smooth boundary. (8 to 12 inches thick)
Bw--14 to 35 inches; dark brown (10YR 4/3) gravelly loam, yellowish brown (10YR 5/4) dry; weak medium and fine subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic and weakly smeary; common fine and very fine roots; common medium, fine and very fine tubular pores; 20 percent gravel-size basalt fragments; strongly acid (pH 5.4); abrupt irregular boundary. (8 to 24 inches thick)
R--35 inches; fractured basalt.
TYPE LOCATION: Wahkiakum County, Washington; on Crown Zellerbach road 520; 300 feet south and 750 feet east of northwest corner section 4, T. 10 N., R. 5 W.
RANGE IN CHARACTERISTICS: The average annual soil temperature is estimated to range from 43 to 46 degrees F. Depth to the lithic contact ranges from 20 to 40 inches. The particle-size control section averages 20 to 30 percent apparent clay and 15 to 30 percent rock fragments.
The A horizon has hue of 5YR to 10YR, value of 2 or 3 moist, 3 to 5 dry, and chroma of 1 to 3 moist, 2 through 4 dry. This horizon has medium, fine, and very fine subangular blocky structure. It is strongly acid or very strongly acid.
The Bw horizon has hue of 7.5YR or 10YR, value of 3 or 4 moist, 4 to 6 dry, and chroma of 3 to 6 moist and dry. It is moderately acid or strongly acid. Texture is gravelly silt loam or gravelly loam.
COMPETING SERIES: These are the Beigle, Hyas, Jonas, Moe, Murnen, Vailton, Wilhoit and Xeno series. All of these soils are more than 40 inches deep to a lithic contact.
GEOGRAPHIC SETTING: These soils formed in material weathered from basalt and basaltic breccia with an admixture of volcanic ash in the upper part on mountain slopes. Elevation ranges from 1,600 to 2,700 feet. Slopes are 5 to 90 percent. These soils have a coastal marine climate with cool wet winters and cool dry summers. Average annual precipitation is 70 to 120 inches. The average January temperature is about 28 degrees F; the average July temperature is about 60 degrees F; the average annual temperature is 42 to 45 degrees F. The growing season (28 degrees F) is 150 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Boistfort, Bunker, and Squally soils and the competing Murnen soils. Boistfort, Bunker and Squally soils have a mesic temperature regime. Also, Squally soils are medial-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderate permeability.
USE AND VEGETATION: Lates soils are used primarily for timber production. The dominate native vegetation is Douglas-fir, western hemlock, Pacific silver fir, Sitka spruce, bigleaf maple, and western redcedar with an understory of salmonberry, western swordfern, red huckleberry, salal, western brackenfern, trailing blackberry, Oregon oxalis, Oregon fairybells, devilsclub, Pacific trillium, trailing blackberry, queencup beadlily, and vine maple.
DISTRIBUTION AND EXTENT: Southwestern Washington and possibly northwestern Oregon. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wahkiakum County, Washington, 1976.
Classification only updated 3/94. This description reflects a change in classification based on amendment 16. Diagnostic horizons and features recognized in this pedon are a umbric epipedon from the surface to 14 inches, a cambic horizon from 14 to 35 inches and a lithic contact of 35 inches. The particle-size control section has andic soil properties, except that the bulk density is between 0.90 and 1.00 g/cc below a depth of 13 inches.