LOCATION SERPENTANO OREstablished Series
TAXONOMIC CLASS: Loamy-skeletal, magnesic, mesic Dystric Eutrudepts
TYPICAL PEDON: Serpentano very stony loam, on a complex convex east facing slope of 34 percent in a forested area at about 2,700 feet elevation. (Colors are for moist soil unless otherwise noted.)
0i--3 inches to 0; partially decomposed needles and leaves.
A--0 to 5 inches; dark brown (7.5YR 3/4) very stony loam, brown (7.5YR 5/4) dry; moderate fine subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; many very fine and fine roots; few fine tubular and common fine interstitial pores; 20 percent peridotite gravel and 10 percent cobbles; 10 percent of surface covered with stones; slightly acid (pH 6.2); clear wavy boundary. (3 to 7 inches thick)
Bw1--5 to 8 inches; dark brown (7.5YR 4/4) gravelly loam, brown (7.5YR 5/4) dry; moderate fine and medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common very fine, fine, medium, and few coarse roots; few fine tubular pores; 20 percent peridotite gravel and 10 percent cobbles; neutral (pH 6.8); clear wavy boundary.
Bw2--8 to 18 inches; dark brown (7.5YR 4/4) very cobbly loam, brown (7.5YR 5/4) dry; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; common medium and few coarse roots; few very fine and fine tubular pores; 25 percent gravel and 15 percent cobbles; neutral (pH 6.8); gradual wavy boundary. (Combined thickness of Bw horizon is 12 to 22 inches.)
C1--18 to 24 inches; dark yellowish brown (10YR 4/4) very gravelly loam, brown (7.5YR 5/4) dry; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and medium roots; few very fine and fine tubular pores; 45 percent gravel and 15 percent cobbles; neutral (pH 7.0); clear wavy boundary.
C2--24 to 46 inches; dark yellowish brown (10YR 4/4) extremely gravelly loam; 60 percent brown (7.5YR 5/4) dry and 40 percent light brownish gray (2.5Y 6/2) dry; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few interstitial pores; 55 percent gravel and 20 percent cobbles; neutral (pH 7.0); abrupt wavy boundary. (Combined thickness of C1 and C2 horizon is 27 to 36 inches.)
Cr--46 to 60 inches; partially weathered serpentinitic bedrock.
TYPE LOCATION: Coos County, Oregon; about 0.1 mile on Forest Service road 3,260 past the road junction of 3260 A and 3260; 2,600 feet south of the northeast corner, sec. 3, T. 32 S., R. 12 W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is about 47 to 54 degrees F. The soil has a udic moisture regime but has a short dry period of less than 45 consecutive days during the summer. The depth to bedrock is 40 to 60 inches. Gravel and cobbles of serpentinite or peridotite range from 25 to 75 percent throughout the soil and averages more then 35 percent in the particle-size control section. Rock fragments are dominantly hard and unweathered, but range from slightly hard to extremely hard. The soil is slightly acid or neutral. Hue is 10YR through 5YR in the solum.
An 0i horizon up to 3 inches thick is on most locations, with up to 55 percent of stones, cobbles, and gravel of peridotite forming a pavement on the surface.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 to 4 moist and 3 or 4 dry. It has 22 to 27 percent clay with 15 to 30 percent gravel, 5 to 10 percent cobbles, and 10 to 15 percent stones.
The Bw horizon has value of 3 to 5 moist, 4 to 6 dry and chroma of 4 to 6 moist and dry. It is loam or clay loam, with 22 to 32 percent clay and is gravelly, very gravelly, or very cobbly. It has 20 to 40 percent gravel, 10 to 15 percent cobbles, and 0 to 5 percent stones.
The C horizon has hue of 10YR, 7.5YR or 2.5Y, value of 4 to 6 moist, 5 or 6 dry, and chroma of 2 to 6 moist and dry. It is loam or clay loam with 22 to 32 percent clay and is very gravelly, extremely gravelly, very cobbly, or extremely cobbly. It has 35 to 55 percent gravel, 10 to 20 percent cobbles, and 0 to 5 percent stones.
COMPETING SERIES: This is the Mislatnah series. Mislatnah soils are 20 to 40 inches deep to bedrock.
GEOGRAPHIC SETTING: Serpentano soils occur on coastal hills and mountains at elevations of 1,000 to 3,900 feet. Slopes range from 3 to 70 percent. The soils formed in colluvium and residuum weathered from serpentinite and peridotite. The climate is characterized by cool, wet winters and hot, moist summers. The mean annual precipitation is 90 to 130 inches. Mean January temperature is about 40 degrees F, mean July temperature is about 61 degrees F, and the mean annual temperature is 45 to 53 degrees F. The frost-free period is 120 to 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Digger, Greggo, Mislatnah, Preacher, Remote, and Umpcoos soils. All of these soils except Greggo and Mislatnah have mixed mineralogy. Greggo and Mislatnah soils have serpentinitic minerology. Digger soils are 20 to 40 inches deep to bedrock. Preacher soils have less than 35 percent rock fragments and are strongly acid or very strongly acid. Remote soils are strongly acid or very strongly acid. Umpcoos soils are 10 to 20 inches deep to bedrock. All of these soils occur on ridgetops and side slopes of mountains.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderate permeability.
USE AND VEGETATION: Wildlife habitat and timber production. Native vegetation is incense cedar, Port-Orford cedar, Douglas-fir, western redcedar, tanoak, Pacific madrone, Jeffrey pine, western white pine, Pacific rhododendron, salal, oceanspray, low Oregongrape, serviceberry, western swordfern, huckleberry oak, California buckthorn, manzanita and red huckleberry.
DISTRIBUTION AND EXTENT: Coast Range Mountains of western Oregon; MLRA 1. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Coos County, Oregon, 1983.
REMARKS: Diagnostic horizons and features recognized:
Ochric epipedon
Cambic horizon - from 5 to 18 inches (Bw1 and Bw2 horizons)
Particle-size control section - from 10 to 40 inches (part of Bw2, C1, and upper C2 horizon)