LOCATION SNOWLIN OREstablished Series
TAXONOMIC CLASS: Fine-loamy, isotic Andic Humicryepts
TYPICAL PEDON: Snowlin gravelly loam, forested. (Colors are for moist soils unless otherwise noted.)
O--0 to 2.5 inches; loose litter of undecomposed twigs, needles, cones and leaves and partially decomposed twigs, needles, cones and leaves.
A1--2.5 to 7 inches; very dark brown (10YR 2/2) gravelly loam, dark grayish brown (10YR 4/2) dry; moderate fine and very fine granular structure; soft, friable, nonsticky and nonplastic; many very fine to medium roots; many fine irregular pores; 5 percent pumice and many dark colored fine concretions; 20 percent gravel and 5 percent cobbles and stones; strongly acid (pH 5.4); gradual wavy boundary. (3 to 9 inches thick)
A2--7 to 14 inches; very dark brown (10YR 2/2) gravelly loam, dark grayish brown (10YR 4/2) dry; moderate fine granular structure; soft, friable, nonsticky and nonplastic; many very fine to medium roots; many fine irregular pores; 20 percent gravel and 5 percent cobbles and stones; 5 percent pumice and many dark colored fine concretions; white mycelia present; strongly acid (pH 5.2); clear wavy boundary. (3 to 9 inches thick)
A3--14 to 22 inches; very dark grayish brown (10YR 3/2) gravelly loam, dark brown (10YR 4/3) dry; moderate fine and medium granular structure; soft, friable, nonsticky and nonplastic; common very fine to medium roots; many very fine and fine irregular pores; 10 percent gravel and 5 percent cobbles and stones; 5 percent pumice; strongly acid (pH 5.3); abrupt wavy boundary. (5 to 8 inches thick)
2BA--22 to 36 inches; very dark yellowish brown (10YR 3/4) cobbly clay loam, pale brown (10YR 6/3) dry; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine to medium roots; common very fine and fine pores; 20 percent cobbles and stones and 10 percent gravel; strongly acid (pH 5.2); gradual wavy boundary. (0 to 18 inches thick)
2Bw1--36 to 41 inches; dark yellowish brown (10YR 3/4) cobbly clay loam, pale brown (10YR 6/3) dry; moderate fine and very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine to medium roots; common very fine pores; 15 percent cobbles and 5 percent gravel fine pumice fragments; strongly acid (pH 5.1); clear wavy boundary. (3 to 6 inches thick)
2Bw2--41 to 52 inches; dark yellowish brown (10YR 3/4) clay loam, brown (10YR 5/3) dry; moderate very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine pores; 5 percent rock fragments; common fine pumice fragments; very strongly acid (pH 5.0); gradual wavy boundary. (6 to 14 inches thick)
2BC--52 to 62 inches; dark brown (10YR 4/3) clay loam, brown (10YR 5/3) dry; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; common very fine pores; 10 percent rock fragments; very strongly acid (pH 5.0); gradual wavy boundary. (0 to 12 inches thick)
2C--62 to 71 inches; brown (10YR 4/3) cobbly clay loam, brown (10YR 5/3) dry; massive; hard, friable, slightly sticky and slightly plastic; common very fine pores; 20 percent cobbles and stones and 10 percent gravel; very strongly acid (pH 4.9).
TYPE LOCATION: Douglas County, Oregon; SE1/4SE1/4 sec. 30, T. 27 S., R. 3 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 42 to 47 degrees F; and the mean summer soil temperature is 44 to 47 degrees F. The soil are usually moist but are dry 30 to 60 consecutive days during the summer. The umbric epipedon is 10 to 20 inches thick. Depth to bedrock is 60 inches or more. Thickness of the solum is from 30 to 70 inches. The particle-size control section averages 15 to 35 percent rock fragments and 27 to 35 percent clay. Stone lines are common in some pedons in areas with slopes greater than 10 percent.
The A horizon has hue of 10YR, 7.5YR, or 5YR, value of 2 or 3 moist and 3 through 5 dry and chroma of 1 or 2 moist and dry in the upper part and value of 2 or 3 moist and 4 or 5 dry and chroma of 2 or 3 moist and dry in the lower part. It has 15 to 30 percent gravel and 0 to 10 percent cobbles. It has a moist bulk density of 0.85 to 0.95 g/cubic centimeter. It is strongly to slightly acid.
The 2Bw horizon has hue of 10YR, 7.5YR, or 5YR, value of 3 or 4 moist and 4 through 6 dry and chroma of 2 through 4 moist and dry. It is gravelly or cobbly clay loam with 27 to 35 percent clay, 0 to 25 percent cobbles and 0 to 20 percent gravel.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: The Snowlin soils are in mountainous uplands at elevations of 4,000 to 6,000 feet. Slopes range from 0 to 60 percent. The soils formed in colluvium weathered basalt and other basic igneous rocks and mixed with ash and pumice in the upper part. The climate is humid with cold wet winters and cool dry summers. The mean annual precipitation is 40 to 70 inches; mean annual temperature is 38 to 45 degrees F; the mean January temperature is about 25 degrees F; and the mean July temperature is about 55 degrees F. The frost free period is less than 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hummington, Rustlerpeak and Whitehorse soils. Hummington and Rustlerpeak soils are loamy-skeletal and 20 to 40 inches deep to bedrock. Whitehorse soils are in associated mountain meadows and dominantly formed in ash in the upper part of the profile.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately slow permeability.
USE AND VEGETATION: Timber production, water supply and wildlife. The vegetation is mainly Douglas fir, noble fir, western hemlock, western white pine and pacific silver fir. The understory is vine maple, rhododendron, huckleberry, ceanothus, serviceberry, and beargrass.
DISTRIBUTION AND EXTENT: West side of the central and southern Cascade Mountains of Oregon. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Douglas County, Oregon, 1975.
REMARKS: Diagnostic horizons and features:
- Umbric epipedon - 2.5 to 22 inches.
- Cambic horizon - 36 to 52 inches.
Classification revised in 2007 from loamy-skeletal, mixed, superactive Andic Humicryepts
In Douglas County, Oregon where the type pedon occurs the soil moistue regime is udic, however in Jackson County, the soil moisture regime is probably xeric.
ADDITIONAL DATA: Characterization data for one profile reported in the Soil Survey of South Umpqua Area, Oregon, 1973. Analyses by Oregon State University.