LOCATION UNDERWOOD WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, isotic, mesic Vitrandic Haploxeralfs
TYPICAL PEDON: Underwood ashy loam - forested, on a 14 percent southeast-facing slope at an elevation of 1,200 feet. (Colors are for moist soil unless otherwise noted. All textures are apparent field textures.)
0i--0 to 1 inch; needles, leaves and twigs.
0a--1 to 2 inches; decomposed organic material.
Ac--2 to 10 inches; dark brown (7.5YR 3/2) ashy loam, brown (7.5YR 4/4) dry; weak coarse granular structure; soft, very friable, slightly sticky, nonplastic and weakly smeary; many fine, and common medium roots; many coarse irregular pores; 35 percent fine shot-like aggregates (2 to 4 mm in size); slightly acid (pH 6.2); clear smooth boundary. (7 to 14 inches thick)
2BA--10 to 21 inches; dark brown (7.5YR 3/4) loam, brown (7.5YR 5/4) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and moderately plastic; common fine and common medium roots; many fine irregular and few fine tubular pores; few gravel; moderately acid (pH 6.0); clear smooth boundary. (10 to l6 inches thick)
2Bt--21 to 37 inches; dark brown (7.5YR 3/4) clay loam, brown (7.5YR 5/4) dry; moderate medium subangular blocky structure; hard, friable, slightly sticky and moderately plastic; few fine, few medium, and few coarse roots; many fine irregular and few fine tubular pores; 5 percent paragravel; common distinct clay films in pores and on faces of peds; strongly acid (pH 5.4); clear wavy boundary. (l6 to 2l inches)
2C--37 to 62 inches; dark yellowish brown (10YR 4/6) loam, brownish yellow (10YR 6/6) dry; common medium distinct mottles of yellowish red (5YR 4/6) moist and dry; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common medium irregular and common medium tubular pores; 15 percent paragravel; very strongly acid (pH 5.1)
TYPE LOCATION: Skamania County, Washington; about l mile south of Willard; 200 feet south and l,700 feet west of the northeast corner of section 11, T. 3 N., R. 9 E. Latitude 45 degrees 45 minutes 55 seconds N. and Longitude 121 degrees 38 minutes 08 seconds W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 50 degrees F. The soil moisture control section is dry in all parts for 45 to 60 consecutive days within the 4 months that follow the summer solstice in 6 or more years out of 10. Solum thickness is 30 to 40 inches. Depth to bedrock is 60 inches or more. Volcanic ash influence is 7 to 14 inches thick and has an estimated moist bulk density of 1.10 to 1.30 g/cc, volcanic glass content of 5 to 30 percent, acid oxalate extractable aluminum plus one-half iron of 1.0 to 2.0 percent, phosphate retention of 50 to 75 percent, and 15 bar water retention of 8 to 12 percent and has l5 to 35 percent shot-like aggregates. The particle-size control section ranges from 25 to 35 percent clay. The control section averages 5 to 30 percent weathered pararock fragments and 0 to 20 percent gravel and cobbles. Below the control section rock fragments range from 0 to 25 percent.
The Ac horizon has hue of 5YR or 7.5YR, value of 3, 4 or 5 dry, 3 or 4 moist and chroma of 2 to 4 moist, 3 to 6 dry.
The Bt horizon has hue of 5YR or 7.5YR, value of 3 or 4 moist, 4 or 5 dry and chroma of 4 to 6 dry. Texture is loam, gravelly loam, or clay loam. Reaction is strongly acid or moderately acid.
The C horizon has hue of 5YR, 7.5YR or 10YR, value of 4 or 5 moist, 5 or 6 dry and chroma of 4 to 6 dry. Texture is loam, gravelly loam, or clay loam. Reaction is strongly acid or moderately acid.
COMPETING SERIES: These are the Bernhill and Wilkesonseries. The Kephart, and McGowan series have a similar classification except for mixed mineralogy and superactive CEC activity class. Bernhill and Cohasset soils are dry for more than 60 consecutive days in the moisture control section. McGowan soils so not have basalt parafragments in the particle-size control section.. Kephart soils are dry for 90 to 130 consecutive days. Wilkeson soils average more than 20 percent rock fragments in the particle-size control section, do not have pararock fragments, and are 60 inches or more to the base of the argillic horizon.
GEOGRAPHIC SETTING: Underwood soils are on backslopes and footslopes and plateaus at elevations of 500 to 2,700 feet. Slopes are 2 to 50 percent. The soil formed in residuum and colluvium from basalt and andesite with a thin mantle of volcanic ash. The climate is characterized by warm and dry summers and cold and wet winters with intermittent snow cover. The mean annual precipitation is 35 to 65 inches. The mean January temperature is about 27 degrees F. and the mean July temperature is about 66 degrees F. The mean annual temperature is 45 to 48 degrees F. The frost-free season is 100 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chemawa, McElroy, Timberhead and Undusk soils on nearby landscapes. Chemawa and Timberhead soils are ashy. McElroy and Undusk soils are skeletal. Also, Timberhead and Undusk soils are frigid.
DRAINAGE AND PERMEABILITY: Well drained, medium to rapid runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used for timber production, some orchards and homesites, wildlife habitat, and livestock grazing. Native vegetation is Douglas-fir, bigleaf maple, vine maple, salal, starflower, and western brackenfern.
DISTRIBUTION AND EXTENT: Southeastern Skamania County and western Klickitat County, Washington. MLRA 6. The series is of small extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Skamania County, Washington, l947.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from 2 to 21 inches
Argillic horizon - the zone from 21 to 37 inches
Vitrandic subgroup feature - the zone from 2 to 10 inches
Particle-size control section - the zone from 21 to 37 inches
Depths to diagnostic horizons and features are measured from the top of the first mineral layer.