LOCATION GRAVES WAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, ferrihydritic Lithic Haplocryands
TYPICAL PEDON: Graves extremely cobbly medial sandy loam - forestland, on a 67 percent slope with a northeasterly aspect at an elevation of 3,360 feet in a Pacific silver fir/Alaska huckleberry plant association. (When described on September 16, 1992, the soil was dry throughout. Colors are for moist soil unless otherwise stated. All textures are apparent field textures.)
Oi--0 to 3 inches; slightly decomposed needles, leaves and twigs; abrupt smooth boundary. (1 to 3 inches thick)
A--3 to 6 inches; dark brown (7.5YR 3/4) extremely cobbly medial sandy loam, strong brown (7.5YR 5/6) dry; weak very fine and fine granular and weak very fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; weakly smeary; many very fine, fine, medium, and coarse roots; many very fine and fine irregular pores; 30 percent gravel, 40 percent cobbles; very strongly acid (pH 4.6); clear smooth boundary. (1 to 5 inches thick)
Bw--6 to 9 inches; dark reddish brown (5YR 3/4) extremely cobbly medial sandy loam, strong brown (7.5YR 5/6) dry; weak very fine and fine granular and weak very fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; weakly smeary, many very fine, fine, medium, and coarse roots; common very fine and fine irregular pores; 30 percent gravel, 45 percent cobbles; very strongly acid (pH 4.8); abrupt wavy boundary. (3 to 15 inches thick)
R--9 inches; hard marine basalt.
TYPE LOCATION: Mason County, Washington, about 1 mile south-southwest of Lena Creek Campground, about 800 feet east and 2,050 feet south of the northwest corner of Section 12, T. 24 N., R. 4 W. (Latitude 47 degrees, 35 minutes, 09 seconds N., Longitude 123 degrees, 08 minutes, 30 seconds W.)
RANGE IN CHARACTERISTICS: Mean annual soil temperature at the lithic contact is 41 to 43 degrees F. Mean summer soil temperature is 43 to 47 degrees F. Mean winter soil temperature is 37 to 41 degrees F. These soils are usually moist, and are dry in the soil moisture control section for 0 to 30 consecutive days following the summer solstice; udic moisture regime. Depth to bedrock is 4 to 10 inches. The particle-size control section from the mineral soil surface to the bedrock contact has 60 to 90 percent rock fragments by volume and andic soil properties. The andic soil material has an estimated moist bulk density of 0.50 to 0.80 g/cc, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 2 to 3 percent, phosphate retention of 85 to 100 percent and 15-bar water retention of 20 to 35 percent for air dried samples. Acid oxalate extractable iron is 1.5 to 3.0 percent. Organic matter is 10 to 20 percent. It has 2 to 5 cmol/kg of aluminum.
The A horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist and 4 or 5 dry, and chroma of 3 or 4 moist.
The Bw horizon has hue of 10YR, 7.5YR, or 5YR, value of 3 or 4 moist and 5 or 6 dry, and chroma of 4 or 6 moist and 5 or 6 dry. It is extremely cobbly medial sandy loam, extremely gravelly medial sandy loam, or extremely cobbly medial loam.
COMPETING SERIES: These are the Buckman, Bungalow, Constance, Weatherwax and Yellowstone series. Buckman, Bungalow and Constance soils have less than 2 cmol/kg of aluminum. Weatherwax soils have a perudic moisture regime. Yellowstone soils have an umbric epipedon and are shallow. Constance soils are shallow to bedrock.
GEOGRAPHIC SETTING: Graves soils are on mountain slopes. Slopes are 60 to 100 percent. The soils formed in colluvium from marine basalt and associated volcanic rocks. Elevations are 2,650 to 3,900 feet. Average annual precipitation is 70 to 150 inches. Average annual temperature is 39 to 41 degrees F. The frost-free season is 120 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Brokenfinger and Lilliwaup soils. Brokenfinger soils are on mountain slopes and are moderately deep to bedrock. Lilliwaup soils are on mountain slopes and are very deep.
DRAINAGE AND PERMEABILITY: Well drained; moderately rapid permeability.
USE AND VEGETATION: Wildlife habitat, recreation, and watershed. Native vegetation is Western hemlock, Pacific silver fir, vine maple, Alaska huckleberry, Oregon-grape, Pacific rhododendron, red huckleberry, common beargrass, northern twinflower, and vanillaleaf.
DISTRIBUTION AND EXTENT: Olympic Mountains of Mason and Jefferson Counties, Washington; MLRA 3. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Mason County, Washington, 2000; Olympic National Forest.
REMARKS: Diagnostic horizons and features recognized in this pedon are ochric epipedon, andic soil properties from 3 to 9 inches, and a lithic contact at 9 inches. The particle-size control section is from 3 to 9 inches (A and Bw horizons). The soil meets all requirements for Fulvi great group except for thickness. The soil meets Alic subgroup requirements.