LOCATION FIROKE             WA

FIROKE SERIES

TAXONOMIC CLASS: Ashy-skeletal, amorphic, frigid Humic Vitrixerands

TYPICAL PEDON: Firoke ashy fine sandy loam - forested on a 12 percent southwest-facing backslope at an elevation of 3,120 feet. (Colors are for dry soil unless otherwise noted. All textures are apparent field textures.)

A--0 to 6 inches; brown (10YR 4/3) ashy fine sandy loam, dark brown (7.5YR 3/2) crushed moist; weak very fine granular structure parting to weak fine granular; soft, very friable, nonsticky and nonplastic; weakly smeary; many very fine and common coarse roots; many very fine and fine interstitial pores; 12 percent gravel from igneous rocks; slightly acid (ph 6.2); clear smooth boundary. (6 to 10 inches thick)

AB--6 to 19 inches; yellowish brown (10YR 5/4) gravelly ashy fine sandy loam; dark brown (10YR 3/3) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; weakly smeary; many very fine and common coarse roots; many very fine and fine interstitial pores; 25 percent gravel; slightly acid (pH 6.2); clear smooth boundary. (4 to 10 inches thick)

Bw1--19 to 28 inches; yellowish brown (10YR 5/4) very cobbly ashy sandy loam; brown (7.5YR 5/4) moist; weak fine subangular blocky structure parting to weak very fine subangular blocky; soft, very friable, nonsticky and nonplastic; weakly smeary; many very fine and few coarse roots; many very fine interstitial and common fine tubular pores; 20 percent gravel and 15 percent cobbles; slightly acid (pH 6.4); clear smooth boundary.

Bw2--28 to 34 inches; light yellowish brown (10YR 6/4) extremely cobbly ashy sandy loam; dark brown (7.5YR 3/4) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky and nonplastic, weakly smeary; many very fine and few fine roots; many very fine and fine interstitial pores; 40 percent gravel and 25 percent cobbles; slightly acid (pH 6.4); gradual smooth boundary.

Bw3--34 to 44 inches; light yellowish brown (10YR 6/4) extremely stony ashy loam; dark yellowish brown (10YR 4/4) moist; weak very fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic, weakly smeary; common very fine and few fine roots; common very fine and fine interstitial pores; 30 percent gravel, 10 percent cobbles and 30 percent stones; slightly acid (pH 6.4); gradual smooth boundary.

Bw4--44 to 60 inches; light yellowish brown (10YR 6/4) extremely gravelly ashy loam; dark yellowish brown (10YR 4/4) moist; weak very fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic, weakly smeary; common very fine and few fine roots; common very fine interstitial pores; 55 percent gravel, 15 percent cobbles and 5 percent stones from ejecta; slightly acid (pH 6.4). (Combined thickness of the Bw horizon is 40 inches or more)

TYPE LOCATION: Klickitat County, Washington; about 5.5 miles east of Trout Lake; 800 feet north and 2,500 feet east of the southwest corner, section 15, T. 6 N., R. 11 E. Latitude 46 degrees, 00 minutes, 20 seconds N. and Longitude 121 degrees, 25 minutes, 00 seconds W.

RANGE IN CHARACTERISTICS: The mean annual soil temperature is 43 to 46 degrees F. The soil moisture control section is usually moist, but is dry in all parts for 60 to 75 consecutive days. The 0 to 40 inch particle-size control section has an estimated moist bulk density of 0.60 to 0.90 g/cc, volcanic glass content of 30 to 60 percent, acid oxalate extractable aluminum plus one-half iron of 2.0 to 3.0 percent and phosphate retention of 85 to 98 percent. The umbric epipedon is 10 to 20 inches thick with a base saturation (NH4OAC) of 15 to 30 percent. Rock fragments in the upper part of the particle-size control section range from 20 to 35 percent. The weighted average of rock fragments in the particle-size control section is 35 to 45 percent. Reaction is slightly acid or moderately acid. Surface stones range from 0.01 to 0.10 percent.
The A horizon has hue of 7.5YR or 10YR, value of 4 or 5 dry and chroma of 3 or 4 dry, 2 or 3 moist.
The AB horizon has hue of 7.5 or 10YR, value of 4 or 5 dry, 2 or 3 moist and chroma of 3 or 4 dry, 2 or 3 moist. Texture is gravelly ashy loam, cobbly ashy sandy loam, gravelly ashy sandy loam, or gravelly ashy fine sandy loam.
The Bw horizon has hue of 7.5YR or 10YR, value of 5 or 6 dry and 3 or 4 moist. Texture is very cobbly ashy sandy loam, extremely cobbly ashy sandy loam, extremely stony ashy loam, extremely gravelly ashy loam, or very gravelly ashy loam. Rock fragments range from 20 to 35 percent in the upper part to 55 to 75 percent in the lower part.

COMPETING SERIES: There are no competing series.
Series with a similar classification are the Fryrear, Pipp, Slicklog, Timberbutte and Yapoah series.
Fryrear soils 20 to 40 inches to lithic contact (basalt); dry for 90 to 110 consecutive days following the summer solstice; glassy mineralogy
Pipp soils 40 to 60 inches to lithic contact (andesite); dry for 90 to 110 consecutive days following the summer solstice; glassy mineralogy
Slicklog soils dry for 45 to 60 consecutive days following the summer solstice; mixed mineralogy
Timberbutte soils ashy-skeletal over loamy-skeletal; mollic epipedon 20 to 30 inches thick
Tumac soils mixed mineralogy; 5 to 30 percent volcanic glass in pscs
Yapoah soils 60 to 80 percent volcanic glass in pscs; glassy mineralogy

GEOGRAPHIC SETTING: Firoke soils are on mountain slopes at elevations of 2,000 to 4,200 feet. Slopes are 5 to 40 percent. The soils formed in residuum and colluvium derived 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 40 to 55 inches. The average January temperature is 23 degrees F. and the average July temperature is 63 degrees F. The mean annual temperature is 39 to 45 degrees F. The frost-free season is 70 to 95 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Kingtain, Guler, and McCumber soils. Guler soils are on foot slopes and are mesic. McCumber soils are on mountain side slopes and are loamy-skeletal. Kingtain soils have an argillic horizon and are on mountain side slopes.

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

USE AND VEGETATION: These soils are used mainly for timber production, livestock grazing and wildlife habitat. Native vegetation is mainly Douglas-fir, ponderosa pine, grand fir, Oregon white oak, with an understory of western hazel, prince's pine, pinegrass, elk sedge, arrowleaf balsamroot, common snowberry, Pacific dogwood, Oregon-grape, and creambush oceanspray.

DISTRIBUTION AND EXTENT: Klickitat and Yakima Counties, Washington; MLRA 6. The series is moderately extensive.

MLRA OFFICE RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: Klickitat County, Washington, 2003.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Umbric epipedon - the zone from 0 to 19 inches
Cambic horizon - the zone from 19 to 60 inches
Andic soil properties - the zone from 0 to 60 inches (A, AB, Bwl, Bw2, Bw3, Bw4)
Ashy particle-size class - from 0 to 19 inches
Ashy-skeletal particle-size class - from 19 to 60 inches
Classification revision 9/93 from medial-skeletal, frigid Andic Xerumbrepts to ashy-skeletal, frigid Humic Vitrixerands
Further investigation is needed to support the current separation between the Firoke and Tumac series. The Firoke series concept recognizes amorphic mineralogy and a volcanic glass content of 30 to 60 percent. It is also correlated to the ponderosa pine - Oregon white oak plant association group. The Tumac series concept recognizes mixed mineralogy and a volcanic glass content of 5 to 30 percent. It is correlated to the grand fir - Douglas-fir plant association group.

ADDITIONAL DATA: NSSL data is available for this pedon; NSSL pedon number 87P0059.