LOCATION ISELLA WAEstablished Series
TAXONOMIC CLASS: Medial, amorphic Andic Humicryods
TYPICAL PEDON: Isella medial loam - forested, on a 20 percent, southeast-facing concave slope at an elevation of 5,680 feet. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)
Oi--0 to 1 inch; slightly decomposed forest litter, loose needles, twigs, and cones. (1/2 to 2 inches)
Oa--1 to 3 inches; highly decomposed black (10YR 2/1) moist, organic matter. (2 to 5 inches thick)
E--3 to 5 inches; pinkish gray (5YR 7/2) medial fine sandy loam, reddish gray (5YR 5/2) moist; moderate fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic and nonsmeary; common very fine, fine, medium and coarse roots; common very fine tubular pores; NaF pH 10.0; strongly acid (pH 5.2); abrupt wavy boundary. (1 to 3 inches thick)
Bhs--5 to 9 inches; reddish brown (5YR 5/3) medial loam, dark reddish brown (5YR 3/3) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, nonsticky, slightly plastic and weakly smeary; common very fine and fine, few coarse and medium roots; common very fine tubular pores; NaF pH 12.0+; strongly acid (pH 5.4); clear irregular boundary. (1 to 6 inches thick)
Bs--9 to 23 inches; yellowish red (5YR 5/6) medial loam, yellowish red (5YR 4/6) moist; strong fine and medium subangular blocky structure; hard, firm, nonsticky, slightly plastic and weakly smeary; common fine and medium, few coarse roots; common very fine tubular pores; NaF pH 12.0+; strongly acid (pH 5.4); abrupt wavy boundary. (6 to 18 inches thick)
Bw--23 to 48 inches; very pale brown (10YR 7/4) medial fine sandy loam, yellowish brown (10YR 5/4) moist, small areas of iron staining appearing as few fine prominent reddish yellow (7.5YR 6/6) mottles, strong brown (7.5YR 5/6) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, nonsticky and nonplastic, weakly smeary; few medium roots; few very fine tubular pores; NaF pH 12.0; moderately acid (pH 5.8); clear wavy boundary. (0 to 25 inches thick)
2Bsb--48 to 53 inches; yellowish brown (10YR 5/4) medial loam, dark yellowish brown (10YR 3/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, nonsticky, slightly plastic and weakly smeary; few very fine tubular pores; NaF pH 12.0; moderately acid (pH 5.6); clear wavy boundary. (5 to 14 inches thick)
2Bwb--53 to 63 inches; light yellowish brown (10YR 6/4) medial sandy loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, nonsticky, slightly plastic, and weakly smeary; few very fine tubular pores; 10 percent pebbles; NaF pH 12.0; moderately acid (pH 5.6)
TYPE LOCATION: Chelan County, Washington; about 5.5 miles east of Holden Village; off of Forest Service Trail #1256 near Lyman Lake camp ground; 2,500 feet east and 2,600 feet north of southwest corner of section 7, T. 31 N., R. 16 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 38 to 41 degrees F. These soils are usually moist, but are dry in all parts for 30 to 45 consecutive days following the summer solstice. The particle-size control section has an estimated moist bulk density of 0.60 to 0.85 g/cc, volcanic glass content of 30 to 60 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of more than 2.0 percent, 15-bar water retention of 12 to 15 percent for air dried samples, and 0 to 10 percent rock fragments.
The E horizon has hue of 5YR through 10YR, value of 5 through 7 dry, 3 through 5 moist, and chroma of 1 or 2 moist or dry. Reaction is strongly acid or moderately acid.
The Bhs horizon has hue of 5YR or 7.5YR, value of 4 or 5 dry, 3 or 4 moist and chroma of 3 or 4 moist or dry. Reaction is strongly acid or moderately acid.
The Bs horizon has hue of 5YR or 7.5YR, value of 5 or 6 dry, 3 through 5 moist, and chroma of 4 through 6 moist or dry. Textures are medial loam or medial fine sandy loam. Reaction is strongly acid or moderately acid.
The Bw horizon has hue of 7.5YR or 10YR, value of 6 or 7 dry, 4 or 5 moist, and chroma of 3 or 4 moist or dry. Textures are medial loam, medial fine sandy loam, or medial very fine sandy loam. Reaction is moderately acid or slightly acid. Some pedons do not have a Bw horizon.
Some pedons have a 2Eb horizon.
The 2Bsb horizon has hue of 5YR, 7.5YR, or 10YR, value of 5 or 6 dry, 3 or 4 moist and chroma of 4 through 6 moist or dry. Textures are medial loam or medial fine sandy loam. Rock fragments range from 0 to 10 percent by volume. Reaction is moderately acid or slightly acid.
The 2Bwb horizon has hue of 10YR or 2.5Y, and value of 6 or 7 dry, 3 through 5 moist. Textures are medial sandy loam, gravelly medial loam, or gravelly medial sandy loam. Coarse fragments range from 10 to 25 percent by volume. Reaction is moderately acid or slightly acid.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: Isella soils are in cirque basins and adjacent mountain slopes on all aspects. Slopes range from 3 to 60 percent. Elevations range from 4,000 to 6,000 feet. These soils are formed in deep volcanic ash, with small amounts of colluvial coarse fragments in the lower horizons. The climate is characterized by cool, dry summers and cold, moist winters. The average annual precipitation is 80 to 120 inches. The mean January temperature is about 21 degrees F, the mean July temperature is about 53 degrees F, and the mean annual temperature is 38 to 42 degrees F. The growing season at 28 degrees F is about 80 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Totem, Fernow, Reggad, and Nimue soils. Fernow and Totem soils have greater than 35 percent pumice fragments by volume within the particle-size control section. Nimue soils are medial-skeletal. Reggad soils are fragmental and lack a spodic horizon.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is moderate.
USE AND VEGETATION: Woodland, wildlife habitat, watershed and recreation. Native vegetation is subalpine fir, mountain hemlock, Engelmann spruce, Pacific silver fir, and some whitebark pine with an understory of huckleberry, Cascade azalea, pachystima, lupine, Sitka mountain ash, alder buckthorn, and tree seedlings.
DISTRIBUTION AND EXTENT: East slopes of the Cascade Mountains in Chelan County, Washington. Series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Chelan County, Washington, 1995.
REMARKS: Diagnostic horizons and features recognized in this pedon are an albic horizon from the mineral surface to 2 inches and a spodic horizon 5 to 23 inches that has a ratio of free iron to carbon of less than 0.2 in the upper 4 inches.