LOCATION STILGAR WAEstablished Series
TAXONOMIC CLASS: Ashy-skeletal, amorphic Humic Vitricryands
TYPICAL PEDON: Stilgar gravelly ashy sandy loam -- under a coniferous forest on a 50 percent southwest-facing slope at an elevation of 5,100 feet. The soil was moist when described. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)
Oi--0 to 1 inch; slightly decomposed needles and twigs; abrupt smooth boundary. (0 to 1 inch thick)
A--1 to 9 inches; dark grayish brown (10YR 4/2) gravelly ashy sandy loam, very dark brown (10YR 2/2) moist; weak medium granular structure; soft, very friable, nonsticky and nonplastic, weakly smeary; common fine and medium roots; many very fine and fine irregular pores; 30 percent gravel; NaF pH 9.4; moderately acid (pH 5.6); clear wavy boundary. (6 to 10 inches thick)
AB--9 to 18 inches; brown (10YR 4/3) very gravelly ashy sandy loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic, weakly smeary; common very fine and fine roots; many very fine and fine irregular pores; 40 percent gravel; NaF pH 10.0; strongly acid (pH 5.4); gradual wavy boundary. (0 to 12 inches thick)
Bw--18 to 38 inches; yellowish brown (10YR 5/4) very gravelly ashy loam, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic, weakly smeary; common very fine roots; common very fine irregular pores; 50 percent gravel; NaF pH 10.6; strongly acid (pH 5.4); gradual wavy boundary. (15 to 50 inches thick)
2BC--38 to 60 inches; yellowish brown (10YR 5/4) extremely cobbly loam, dark yellowish brown (10YR 3/4) moist; massive; soft, very friable, nonsticky and slightly plastic, weakly smeary; few very fine roots; common very fine irregular pores; 35 percent gravel and 35 percent cobbles; NaF pH 10.5; strongly acid (pH 5.4).
TYPE LOCATION: Kittitas County, Washington; about 2 miles east of Blowout Mountain; 1,500 feet west and 2.950 feet north of the southeast corner of section 18 T. 19 N., R. 13 E.; USGS Blowout Mountain Washingtontopographic quadrangle; Latitude 47 degrees, 08 minutes, 05 seconds N. and 121 degrees, 15 minutes, 54 seconds W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 39 to 44 degrees F. The soils are usually moist but are dry in all parts in the moisture control section for 25 to 45 consecutive days following summer solstice. The upper 36 inches or more of the solum has 30 to 70 percent volcanic glass, 0.7 to 2.0 percent acid-oxalate extractable aluminum plus one-half iron, 40 to 80 percent phosphate retention, 5 to 12 percent 15-bar moisture content, and 0.85 to 1.10 grams per cubic centimeter estimated moist bulk density. The umbric epipedon ranges from 15 to 20 inches in thickness. The particle-size control section averages 40 to 65 percent rock fragments.
The A horizon has value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3 dry or moist.
The AB horizon, when present, has value of 4 or 5 dry and chroma of 2 or 3 dry or moist. Texture is very gravelly ashy sandy loam, gravelly ashy sandy loam or very gravelly ashy loam. It averages 40 to 55 percent gravel. Reaction is moderately acid or strongly acid.
The Bw horizon has hue of 2.5Y, 10YR or 7.5YR, value of 3 to 6 moist, 5 to 7 dry and chroma of 2 to 4 moist or dry. Texture is very gravelly ashy loam, very gravelly ashy sandy loam, extremely gravelly ashy sandy loam or extremely cobble ashy sand loam, or extremely cobbly ashy loam. It averages 35 to 55 percent gravel and 0 to 35 percent cobbles. Reaction is moderately acid or strongly acid.
The 2BC horizon, when present, has value of 3 or 4 moist and chroma of 3 or 4 dry. Texture is extremely cobbly loam, very cobbly loam, extremely gravelly sandy loam or very gravelly loam. It averages 35 to 45 percent gravel and 15 to 35 percent cobbles. Reaction is moderately acid or strongly acid.
COMPETING SERIES: This is the Kabser series. The Kaner soils have a similar family classification. Kabser soils are moderately deep to bedrock. Kaner soils have an umbric epipedon 20 to 35 inches thick and have hue of 2.5Y in the 2BC horizon and are dominated by rock fragments of gneiss and granite origin.
GEOGRAPHIC SETTING: Stilgar soils are on mountain side slopes. Slopes are 30 to 60 percent. These soils formed in colluvium from volcanic ash and colluvium from andesite, basalt, tuff and breccias. Elevations are 4,000 to 6,000 feet. The climate is characterized by cool moist summers and cold wet winters. The mean annual precipitation is 55 to 80 inches. The average January temperature is about 25 degrees F, and the average July temperature is about 60 degrees F. The mean annual temperature is 37 to 43 degrees F. The frost-free season is 35 to 75 days. The growing season at 28 degrees F is 130 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Currier, Darland, Jimek and Terence soils and the competing Kaner soils. Currier soils are on toeslopes and lack an umbric epipedon. Darland soils are on mountain side slopes,do not have andic soil properties and have a mollic epipedon. Jimek soils are on mountain side slopes and ridges and lack an umbric epipedon. Terence soils are on mountain side slopes, toeslopes, and ridges and have a surface layer less than 14 inches thick which meets andic soil properties.
DRAINAGE AND PERMEABILITY: Well drained; runoff is medium to rapid. Permeability is moderately rapid.
USE AND VEGETATION: These soils are used for timber production, wildlife habitat, and watershed. Vegetation is subalpine fir, Douglas-fir, mountain hemlock, western white pine, and Pacific silver fir with an understory of pachystima, elk sedge, dwarf huckleberry, common snowberry and rusty menziesia.
DISTRIBUTION AND EXTENT: East slopes of the Cascade Mountains in southwestern Kittitas County and western Yakima County, Washington; MLRA 3. This series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Wenatchee National Forest, Yamima County, Washington, 2003. The name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Umbric epipedon - the zone from 1 to 18 inches (A and AB horizons)
Cambic horizon - the zone from 18 to 38 inches (Bw horizon)
Andic soil properties - the zone from 1 to 38 inches
Humic subgroup feature - umbric epipedon from 1 to 18 inches
Particle-size control section - the zone from 1 to 41 inches with the zone from 1 to 38 inches qualifying for ashy-skeletal and the zone from 38 to 41 inches qualifying for loamy-skeletal.
Range in characteristics depth of ash mantle revised in 07/04 from 30 inches to 36 inches to avoid crossing two family classes of ashy-skeletal and ashy-skeletal over loamy-skeletal. Those pedons described with ash mantles between 30 and 36 inches thick will be considered as a taxadjunct to the series.
All depths to diagnostic horizons and features found in the range of characteristics are measured from the top of the first mineral horizon.