LOCATION URBODEN WAEstablished Series
TAXONOMIC CLASS: Medial-skeletal, ferrihydritic, isofrigid Pachic Fulvudands
TYPICAL PEDON: Urboden very gravelly medial silt loam-forestland, on a 68 percent north-northwesterly aspect at an elevation of 1,960 feet in a Pacific silver fir/devilsclub plant association. (When described on February 2, 1994, the soil as moist throughout. Colors are for moist soil unless otherwise stated.)
Oi--0 to 2 inches; slightly decomposed needles, leaves, and twigs; abrupt smooth boundary. (1 to 3 inches thick)
A1--2 to 6 inches; very dark brown (10YR 2/2) very gravelly medial silt loam, very dark grayish brown (10YR 3/2) dry; weak very fine and fine subangular blocky and weak very fine and fine granular structure; hard, friable, nonsticky and nonplastic; weakly smeary; many very fine, fine, medium, and coarse roots; many very fine and fine tubular and irregular pores; 35 percent gravel; moderately acid (pH 5.6); clear smooth boundary.
A2--6 to 13 inches; very dark brown (10YR 2/2) very gravelly medial silt loam, very dark grayish brown (10YR 3/2) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; hard, friable, nonsticky and nonplastic; weakly smeary; many very fine, fine, medium, and coarse roots; many very fine and fine tubular and irregular pores; 30 percent gravel, 5 percent cobbles; strongly acid (pH 5.4); clear wavy boundary.
A3--13 to 24 inches; dark brown (10YR 3/3) very gravelly medial silt loam, yellowish brown (10YR 5/4) dry; weak very fine and fine subangular blocky and weak very fine and fine granular structure; slightly hard, friable, nonsticky and nonplastic; weakly smeary; common very fine, fine, medium, and coarse roots; common very fine and fine tubular and irregular pores; 35 percent gravel, 5 percent cobbles; moderately acid (pH 5.6); clear wavy boundary.
A4--24 to 31 inches; dark brown (10YR 3/3) very gravelly medial silt loam, yellowish brown (10YR 5/4 dry); weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, nonsticky and nonplastic; weakly smeary; common very fine and fine and few medium and coarse roots; common very fine and fine tubular and irregular pores; 30 percent gravel, 5 percent cobbles; moderately acid (pH 5.6); clear wavy boundary. (Combined thickness of the A horizon is 20 to 40 inches.)
Bw1--31 to 42 inches; dark yellowish brown (10YR 3/4) very gravelly medial silt loam, yellowish brown (10YR 5/4) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, nonsticky and nonplastic; weakly smeary; few very fine, fine, medium, and coarse roots; few very fine and fine tubular and irregular pores; 35 percent gravel, 10 percent cobbles; moderately acid (pH 5.8); clear wavy boundary.
Bw2--42 to 62 inches; dark yellowish brown (10YR 3/4) very gravelly medial silt loam, yellowish brown (10YR 5/4) dry; weak very fine, fine, and medium subangular blocky and weak very fine and fine granular structure; slightly hard, friable, nonsticky and nonplastic; weakly smeary; few very fine roots; few very fine and fine tubular and irregular pores; 35 percent gravel, 10 percent cobbles; moderately acid (pH 6.0). (Combined thickness of the Bw horizon is 20 to 40 inches.)
TYPE LOCATION: Clallam County, Washington, about 1 1/2 miles southeast of Beaver Lake, about 1,365 feet east and 2,025 feet south of the northwest corner of Section 14, T. 30 N., R. 12 W. (Latitude 48 degrees, 06 minutes, 03 seconds N., Longitude 124 degrees, 12 minutes, 43 seconds W.)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 43 to 47 degrees F. The mean summer soil temperature is 47 to 50 degrees F. and the mean winter soil temperature is 40 to 45 degrees F. The difference between the mean winter and mean summer soil temperature is 5 to 9 degrees F. These soils are usually moist and have a surplus of available water on a monthly basis throughout the year (perudic). Depth to bedrock is greater than 60 inches. The umbric epipedon is 20 to 40 inches thick. The particle-size control section has andic soil properties with 35 to 90 percent rock fragments by volume. The andic soil material has an estimated moist bulk density of 0.30 to 0.70 g/cc, acid-oxalate extractable aluminum plus one half of the acid-oxalate extractable iron of 2 to 6 percent, phosphate retention of 85 to 100 percent, and 15-bar water retention of 35 to 50 percent for air dried samples. Acid oxalate iron is 2.0 to 3.5 percent. Organic matter is 20 to 40 percent in the umbric epipedon and decreases to 7 percent in the cambic horizon.
The A horizon has value of 2 or 3 moist and 3 through 5 dry and chroma of 2 or 3 moist and 2 or 4 dry. Reaction is strongly or moderately acid. It has 2 to 8 cmol/kg of aluminum.
The Bw horizon has hue of 10YR or 2.5Y moist, value of 3 or 4 moist and 5 through 7 dry, and chroma of 2, 3, 4, or 6 moist and 4 or 6 dry. It is very gravelly medial silt loam, very cobbly medial silt loam, or extremely cobbly medial loam. Reaction is strongly or moderately acid.
COMPETING SERIES: These are the Elklake, Fawceter, Flatbottom, Killam, Larsencreek, McKinnon, and Zenobia soils. Elklake, Killam, Flatbottom and Zenobia soils are moderately deep to bedrock. Fawceter soils are dry for 0 to 30 days. Larsencreek soils have an umbric epipedon 10 to 20 inches thick. McKinnon soils are dry for 0 to 30 days and have a 10 to 20 inch thick umbric epipedon.
GEOGRAPHIC SETTING: Urboden soils are on mountain headwalls. Slopes are 40 to 90 percent. The soils formed in colluvium and residuum from marine basalt and associated volcanic rocks. Elevations are 800 to 2,400 feet. Average annual precipitation is 95 to 120 inches. Average annual temperature is 41 to 43 degrees F. The frost-free season is 120 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Adwell, Eatoncreek, Kaweeta, Lizardlake, Neah, Hyas, and Zenobia soils. Adwell and Hyas soils are on glaciated mountain slopes and both are moderately well drained. Eatoncreek and Lizardlake soils are on glaciated mountain slopes and are shallow. Kaweeta and Zenobia soils are on glaciated mountain slopes and mountain headwalls, respectively, and are moderately deep. Neah soils are on moderate relief mountain slopes and are moderately deep.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Timber production, wildlife habitat, recreation, and watershed. Native vegetation is Pacific silver fir, western hemlock, devilsclub, salmonberry, Alaska huckleberry, deer fern, mosses, and western swordfern.
DISTRIBUTION AND EXTENT: Clallam County, Washington; MLRA 1. Series is of small extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Clallam County, Washington, 2000; Olympic National Forest.
REMARKS: Diagnostic horizons and features recognized in this pedon are the following:
An umbric epipedon from 2 to 31 inches with a depth, thickness and organic carbon requirements of a melanic epipedon (A1, A2, A3 and A4 subhorizons)
Cambic horizon - 31 to 62 inches that meets the requirements for a melanic epipedon but not the color requirements for a melanic or umbric epipedon.
Andic soil properties - 2 to 62 inches (A1, A2, A3, A4, Bw1 and Bw2 subhorizons) based on laboratory data from the Murhut series.
PSCS - 2 to 42 inches (A1, A2, A3, A4, and Bw1 subhorizons)
This soil has a perudic moisture regime.
All depths to diagnostic horizons and features are measured from the top of the first mineral horizon.