LOCATION MCCUMBER WATentative Series
TAXONOMIC CLASS: Ashy-skeletal, glassy, frigid Humic Vitrixerands
TYPICAL PEDON: McCumber stony ashy sandy loam - forested on an 8 percent southeast facing shoulder slope at an elevation of 2,355 feet. (Colors are for dry soil unless otherwise noted. All textures are apparent field textures.)
Oi--0 to 1 inch; needles, leaves and twigs.
Oa--1 to 2 inches; decomposed organic material.
A1--2 to 7 inches; very dark grayish brown (10YR 3/2) stony ashy sandy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine, common medium and few coarse roots; many very fine irregular pores; 5 percent pebbles and 10 percent stones; moderately acid (pH 6.0) clear wavy boundary. (3 to 7 inches thick)
A2--7 to 13 inches; brown (10YR 4/3) gravelly ashy sandy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, friable, nonsticky and nonplastic; many very fine and fine and common medium and coarse roots; many fine irregular pores; 15 percent pebbles and 5 percent cobbles; slightly acid (pH 6.2); gradual wavy boundary. (3 to 7 inches thick)
Bw1--13 to 25 inches; yellowish brown (10YR 5/4) very gravelly ashy sandy loam, dark yellowish brown (10YR 3/4) moist; weak fine subangular blocky structure; soft, friable, nonsticky and nonplastic; many very fine and fine roots; many fine irregular and few fine tubular pores; 30 percent pebbles, 10 percent cobbles and 5 percent stones; slightly acid (pH 6.4); clear wavy boundary. (8 to 16 inches thick)
Bw2--25 to 46 inches; brown (7.5YR 5/4) extremely stony ashy sandy loam, brown (7.5YR 4/4) moist; weak fine subangular blocky structure; soft, friable, nonsticky and nonplastic; weakly smeary; common very fine and fine roots; many very fine and few coarse irregular pores; 40 percent pebbles, 10 percent cobbles and 25 percent stones; slightly acid (pH 6.2); gradual wavy boundary. (12 to 21 inches thick)
Bw3--46 to 60 inches; brown (7.5YR 5/4) extremely stony ashy loam, brown (7.5YR 4/4) moist; weak fine granular structure; soft friable, slightly sticky and slightly plastic; weakly smeary; common very fine and fine roots; common fine and many coarse irregular pores; 45 percent pebbles, 5 percent cobbles and 25 percent stones; slightly acid (pH 6.2).
TYPE LOCATION: Klickitat County, Washington about 5 miles west of Glenwood; 1,750 feet south and 1,000 feet east of the northwest corner of sec. 5, T. 6 N., R. 12 E.
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 60 to 75 consecutive days following summer solstice. Thickness of volcanic ash influence is 60 inches or more. The particle-size control section averages 35 to 65 percent rock fragments and is assumed to be 30 to 60 percent vitric volcanic ash and less than 12 percent 15-bar moisture. The umbric epipedon is 10 to 14 inches thick. The base saturation is assumed to be less than 60 percent throughout. Bulk density of the upper 7 to 14 inches of the soil is estimated to be 0.85 to 0.95 g/cc.
The A horizon has hue of 5YR through 10YR, value of 3 through 5 dry, 2 or 3 moist and chroma of 2 or 3 dry and moist.
The upper part of the Bw horizon has hue of 7.5YR or 10YR, value of 5 or 6 dry, 3 or 4 moist, and chroma of 3 or 4 dry and moist. It is gravelly sandy loam or very gravelly sandy loam.
The lower part of the Bw horizon has hue of 7.5YR or 10YR, value of 5 or 6 dry, 3 or 4 moist, and chroma of 3 or 4 dry and moist. It is loam or sandy loam and is very gravelly, very stony or extremely stony. Reaction is moderately acid or slightly acid.
COMPETING SERIES: These are the Fryrear, Pipp, Silentcone, Timberbutte (T), and Yapoah series. Fryrear and Silentcone series are 20 to 40 inches deep to a lithic contact. Pipp soils are 40 to 60 inches deep to a lithic contact. Timberbutte soils have a mollic epipedon 20 to 30 inches thick and an ash mantle with andic properties 14 to 30 inches thick. Yapoah soils have 25 to 60 percent pumice throughout and have a mollic epipedon 10 to 15 inches thick.
GEOGRAPHIC SETTING: McCumber soils are on mountains, footslopes, and backslopes at elevations of 2,000 to 3,300 feet. Slopes are 2 to 25 percent. The soil formed in volcanic ash and basalt rock fragments. The geologic formation appears to be a block and ash flow. Summers are cool and dry. Winters are cold and wet, with snow cover from December through April. The mean annual precipitation is 35 to 40 inches. The average January temperature is 24 degrees F. and the average July temperature is 63 degrees F. The mean annual temperature is 42 to 46 degrees F. The frost-free season is 80 to l00 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bercumb, Firoke, Guler, Mullig, Pinbit, Trelk and Yedlick soils. Mullig and Pinbit soils are ashy. Firoke soils have less than 30 percent glass. Guler and Trelk soils are mesic. Yedlick soils are loamy-skeletal. Bercumb soils are coarse-loamy.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately rapid permeability.
USE AND VEGETATION: Used mainly for timber production, grazed woodland, and wildlife habitat. Vegetation is mainly ponderosa pine and scattered Douglas-fir with an understory of snowbrush ceanothus, elk sedge, Idaho fescue, pinegrass and goldenweed.
DISTRIBUTION AND EXTENT: East slopes of the Cascade Mountains in Klickitat and Yakima Counties, Washington. MLRA 6.The series is moderately extensive.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Yakima County, Washington, l976.
REMARKS: Diagnostic horizons and features recognized in this pedon are an umbric epipedon from the mineral surface to 11 inches and a cambic horizon from 11 to 60 inches. This series needs further investigation for ranges of andic properties. This soil is currently recognized only within the Yakima Indian Reservation project area. If this series concept results in amorphic mineralogy, the Firoke or Tumac series may be possibilities fo correlation. The Firoke series has 30 to 60 percent glass and is recognized in the MLRA 6 oak-pipo zone. The Tumac series has 5 to 30 percent glass and is recognized in the MLRA 6 abgr-psme zone.
All depths to diagnostic horizons and features are measured from the top of the first mineral horizon.
4/2003- only the remarks paragraph was revised to document possible correlation potential.