LOCATION SKOOKUMHOUSE OREstablished Series
TAXONOMIC CLASS: Fine, mixed, active, mesic Typic Haplohumults
TYPICAL PEDON: Skookumhouse clay loam, woodland. On a 13 percent northeast-facing slope at 1,220 feet elevation. (When described on October 29, 1985, the soil profile was moist throughout. Colors are for moist soils unless otherwise noted.)
0i--1 inch to 0; partially decomposed needles, leaves, twigs, and woody materials.
A--0 to 11 inches; dark reddish brown (5YR 3/3) clay loam, reddish brown (5YR 5/3) dry; strong very fine subangular blocky structure; slightly hard, friable, slightly sticky and plastic; many fine and very fine roots; many fine and very fine irregular pores; 5 percent gravel and 10 percent soft rock fragments; very strongly acid (pH 4.6); abrupt smooth boundary. (10 to 20 inches thick)
Bt1--11 to 25 inches; reddish brown (2.5YR 4/4) silty clay, reddish brown (5YR 5/4) dry; strong very fine subangular blocky structure; hard, firm, sticky and plastic; many fine and very fine roots; many fine and very fine tubular pores; common faint clay films on ped faces and common distinct clay films in pores; 5 percent gravel and 15 percent soft rock fragments; very strongly acid (pH 4.6); gradual smooth boundary.
Bt2--25 to 38 inches; red (2.5YR 4/6) silty clay, reddish brown (2.5YR 5/6) dry; moderate fine subangular blocky structure; hard, firm, sticky and plastic; common fine and very fine roots; many fine and very fine tubular pores; many distinct clay films on ped faces and in pores; 5 percent gravel and 20 percent soft rock fragments; very strongly acid (pH 4.6) clear wavy boundary.
Bt3--38 to 52 inches; red (2.5YR 4/6) clay loam, reddish brown (2.5YR 5/6) dry; weak fine subangular blocky structure; hard, firm, sticky and plastic; few fine and very fine roots; few fine and very fine tubular pores; many distinct clay films on ped faces and in pores; 10 percent gravel and 40 percent soft rock fragments; very strongly acid (pH 4.6); abrupt wavy boundary. (Combined thickness of the Bt horizon is 31 to 41 inches)
Cr--52 inches; partially weathered sandstone.
TYPE LOCATION: Curry County, Oregon; located about 2,310 feet north and 800 feet west of the southeast corner of section 8, T. 40 S., R. 13 W., W. M. (Latitude 42 degrees, 07 minutes, 37 seconds N.; Longitude 124 degrees, 15 minutes, 47 seconds W.)
RANGE IN CHARACTERISTICS: The soils are usually moist and are dry less than 45 consecutive days between 4 and 12 inches in the four months following the summer solstice. The mean annual soil temperature is 47 to 54 degrees F. Depth to a paralithic contact and solum thickness is 40 to 60 inches. The particle-size control section averages 35 to 45 percent clay. The umbric epipedon is 10 to 20 inches thick.
The A horizon has hue of 5YR or 7.5YR, value of 2 or 3 moist, 4 or 5 dry and chroma of 2 or 3 moist and dry. It has 27 to 35 percent clay, 0 to 10 percent gravel, and 0 to 20 percent soft rock fragments.
The Bt horizon has hue of 2.5YR or 5YR, value of 4 or 5 moist, 4 to 6 dry and chroma of 4 to 6 moist and dry. It is silty clay loam, silty clay, or clay loam with 35 to 45 percent clay. It has 5 to 25 percent gravel, 0 to 10 percent cobbles, 5 to 65 percent soft rock fragments.
COMPETING SERIES: These are the Absaquil, Apt, Hazelcamp, McDuff, Peavine and Wintley series. The Apt soils have 45 to 60 percent clay and hues yellower than 5YR in the particle-size control section. Hazelcamp, McDuff and Peavine soils are 20 to 40 inches deep to a paralithic contact. Absaquil and Wintley soils have 10YR or 7.5YR hues in the Bt horizon.
GEOGRAPHIC SETTING: Skookumhouse soils are on broad ridgetops and stable benches of mountains. Slopes are 0 to 30 percent. The soils formed in colluvium and residuum from metasedimentary or metavolcanic rock types of the Dothan Formation. Elevations are 400 to 3,000 feet. The climate is characterized by warm wet winters and hot moist summers. The mean annual precipitation is 90 to 130 inches. 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 Averlande, Bravo, Cassiday, Colepoint, Crutchfield, Fritsland, Hazelcamp, and Grouslous soils. All of these soils occur on ridgetops, benches, or side slopes of mountains. Averlande soils are 10 to 20 inches deep to a lithic contact and are loamy-skeletal. Bravo, Cassiday, Crutchfield and Hazelcamp soils are 20 to 40 inches deep to bedrock. Colepoint soils lack an argillic horizon. Fritsland soils lack an argillic horizon and are fine-loamy. Grouslous soils are 10 to 20 inches deep to bedrock and are loamy-skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow permeability.
USE AND VEGETATION: The soils are mainly used for timber production, limited homesites, watershed, recreation, and wildlife habitat. Vegetation is Douglas fir, tanoak, western hemlock, Pacific madrone, red alder, western swordfern, evergreen huckleberry, cascade Oregongrape, salal, Pacific rhododendron, red huckleberry, Oregon oxalis, common beargrass, western brackenfern, evergreen violet, and western rattlesnake plantain.
DISTRIBUTION AND EXTENT: Mountainous areas of southwestern Oregon; MLRA 1. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Curry County, Oregon, 1995. The source of the name is Skookumhouse Butte in Curry County, Oregon.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Umbric epipedon - from the surface to 11 inches (A horizon).
Argillic horizon - from 11 to 52 inches. (Bt1, Bt2, and Bt3 horizons).
Assume base saturation of less than 35 percent based on lab data from similar soils having same pH.