LOCATION TIMBERHEAD              WA

Established Series
Rev. AG/EH/RJE/RWL
10/2011

TIMBERHEAD SERIES

The Timberhead series consists of very deep, well drained soils that formed in residuum and colluvium from basalt mixed with volcanic ash. Timberhead soils are on mountains and have slopes of 5 to 65 percent. The mean annual precipitation is about 55 inches and the mean annual temperature is about 44 degrees F.

TAXONOMIC CLASS: Ashy, amorphic, frigid Humic Vitrixerands

TYPICAL PEDON: Timberhead gravelly ashy loam-forested on a 30 percent southeast-facing back slope at an elevation of 2,800 feet. (Colors are for dry soils unless otherwise noted. All textures are apparent field textures.)

Oi--0 to 1 inch; slightly decomposed needles, twigs and cones.

A--1 to 9 inches; brown (7.5YR 4/4) gravelly ashy loam, dark brown (7.5YR 3/3) moist; weak very fine granular structure; soft, very friable, slightly sticky, nonplastic, and weakly smeary; many very fine and few fine roots; many very fine irregular pores; 25 percent gravel; moderately acid (pH 5.9); clear smooth boundary. (7 to 9 inches thick)

AB--9 to 29 inches; brown (7.5YR 4/4) gravelly ashy loam, dark brown (7.5YR 3/3) moist; weak very fine subangular blocky structure parting to weak fine granular; soft, very friable, slightly sticky, nonplastic, and weakly smeary; common very fine, fine and medium roots; common fine irregular and common fine tubular pores; 30 percent gravel; moderately acid (pH 6.0); gradual wavy boundary. (11 to 20 inches thick)

Bw--29 to 43 inches; yellowish brown (10YR 5/4) gravelly ashy loam, dark yellowish brown (10YR 4/4) moist; weak very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic, and weakly smeary; few fine and medium roots; common very fine irregular and few very fine tubular pores; 20 percent gravel; moderately acid (pH 6.0); clear smooth boundary. (12 to 16 inches thick)

C--43 to 61 inches; strong brown (7.5YR 5/6) extremely paragravelly ashy loam, brown (7.5YR 4/4) moist; massive; slightly hard, friable, slightly sticky and nonplastic; common fine roots; many fine irregular pores; 70 percent paragravel and 5 percent cobbles; moderately acid (pH 5.9).

TYPE LOCATION: Klickitat County, Washington; about 5 miles west of Husum; 1,200 feet south and 1,600 feet west of the northeast corner, section 30, T. 4 N., R. 10 E. (Latitude 45 degrees, 48 minutes, 33 seconds N. and Longitude 121 degrees, 35 minutes, 37 seconds W.)

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 45 to 47 degrees F. The soil moisture control section is usually moist, but 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. The 0 to 40 inch particle-size control section has an estimated moist bulk density of 0.80 to 0.90 g/cc, volcanic glass content of 5 to 30 percent, acid oxalate extractable aluminum plus one-half iron of 2.0 to 4.0 percent, phosphate retention of 85 to 98 percent, and 15 bar water retention of 8 to 12 percent. On a weighted average, the particle-size control section has 20 to 35 percent basalt rock fragments and 10 to 18 percent apparent clay.
The A horizon has hue of 5YR or 7.5YR, value of 3 or 4 dry and chroma of 2 or 3 moist, 3 or 4 dry. It has 20 to 30 percent gravel and 0 to 3 percent cobbles.
The Bw horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry, 3 or 4 moist, and chroma of 4 to 6 dry. It has 20 to 35 percent gravel and 0 to 3 percent cobbles. Reaction is strongly acid or moderately acid.
The C horizon has chroma of 6 to 8 dry. Texture is extremely paragravelly ashy loam or very paragravelly ashy loam. It has 0 to 10 percent gravel, 0 to 5 percent cobbles and 50 to 85 percent paragravel. Reaction is strongly acid or moderately acid.

COMPETING SERIES: These are the Glen (T), Kreft (T), Sugarbowl, Troutlake, and Volash series.
Glen soils dry for 60 to 75 consecutive days following the summer solstice
Kreft soils dry for 60 to 75 consecutive days following the summer solstice
Sugarbowl soils pscs with less than 15 percent rock fragments; MAST of 43 to 45 degrees F.; lack substratum with 50 to 85 percent pararock fragments
Troutlake soils pscs with 2 to 10 percent rock fragments of alluvial origin; lack substratum with 50 to 85 percent pararock fragments
Volash soils 40 to 60 inches to a lithic contact (basalt); pscs with 0 to 10 percent rock fragments; lack substratum with 50 to 85 percent pararock fragments

GEOGRAPHIC SETTING: Timberhead soils are on mountain slopes at elevations of 1,400 to 4,000 feet. Slopes are 5 to 65 percent. The soils formed in residuum and colluvium from basalt mixed with volcanic ash. Summers are cool and dry and winters are cold and wet, with snow cover from December through April. The mean annual precipitation is 50 to 65 inches. The mean January temperature is about 23 degrees F. and the mean July temperature is about 63 degrees F. The mean annual temperature is 43 to 45 degrees F. The frost-free season is 90 to 120 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are Chemawa, Kingtain, McElroy, and Underwood soils. Chemawa soils are on terraces. Underwood soils are on plateaus. McElroy and Kingtain soils are on mountains. Chemawa, McElroy and Underwood soils are mesic. Kingtain soils are ashy-skeletal.

DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability.

USE AND VEGETATION: These soils are used for timber production, livestock grazing, wildlife habitat, recreation, and watershed. Native vegetation is Douglas-fir, grand fir, western redcedar, and a few western hemlock with an understory of vine maple, dwarf rose, thimbleberry, western raspberry, insideout flower, princes pine, longtube twinflower, fairybells, American trailplant, fat false-Solomons-seal, violet, pyrola, Pacific dogwood, Cascade Oregon-grape and common snowberry.

DISTRIBUTION AND EXTENT: Western Klickitat and Skamania Counties. MLRA 6. The series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Skamania County, Washington, 1981.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon - the zone from 1 to 29 inches
Cambic horizon - the zone from 29 to 43 inches
Particle-size control section - the zone from 1 to 41 inches
Further investigation is needed on soil moisture regime; based on plants, a udic soil moisture regime may be a possibility.

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National Cooperative Soil Survey
U.S.A.