LOCATION BRIGHTWOOD OR
Established Series
Rev. AON/GLG
06/2011
BRIGHTWOOD SERIES
The Brightwood series consists of moderately deep, well drained soils that formed in colluvium weathered tuffs and tuffaceous breccia. Brightwood soils are on smooth and dissected mountain slopes and have slopes of 60 to 90 percent. The mean annual precipitation is about 90 inches and the mean annual temperature is about 48 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, isotic, mesic Typic Humudepts
TYPICAL PEDON: Brightwood extremely gravelly loam, forested. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed; needles, leaves, twigs, cones
A1--1 to 5 inches; very dark brown (10YR 2/2) extremely gravelly loam, brown (10YR 4/3) dry; moderate fine and very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 80 percent angular tuffaceous gravel; many roots; many very fine, fine and medium irregular pores; moderately acid (pH 5.6); clear wavy boundary. (2 to 8 inches thick)
A2--5 to 11 inches; very dark grayish brown (10YR 3/2) extremely gravelly loam, dark brown (10YR 3/3) crushed; brown (10YR 5/3) dry; moderate fine and very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; 65 percent angular tuffaceous gravel; many roots; many very fine, fine and medium irregular pores; moderately acid (pH 5.8); gradual wavy boundary. (3 to 12 inches thick)
Bw--11 to 19 inches; dark yellowish brown (10YR 3/4) extremely gravelly loam, yellowish brown (10YR 5/4) dry; weak very fine and fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; 70 percent angular tuffaceous gravel; many roots; many very fine, fine and medium irregular pores; slightly acid (pH 6.1); clear wavy boundary. (6 to 18 inches thick)
C--19 to 31 inches; dark yellowish brown (10YR 3/4) extremely gravelly loam, yellowish brown (10YR 5/4) dry; massive; soft, very friable, slightly sticky and slightly plastic; 60 percent angular tuffaceous gravel; many roots; many very fine, fine and medium irregular pores; moderately acid (pH 5.8); abrupt irregular boundary. (6 to 36 inches thick)
R--31 inches; massive tuffaceous bedrock.
TYPE LOCATION: Clackamas County, Oregon; along the Salmon River road, NW1/4NW1/4 section 27, T. 3 S., R. 7 E., W. M.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 53 degrees F. The soils have a udic moisture regime but they have a short dry period of less than 45 consecutive days during the summer. Thickness of the solum is 15 to 30 inches. It is moderately or slightly acid. Depth to bedrock is 20 to 40 inches. Coarse fragments in the 10- to 40-inch control section range from 35 to 80 percent. The umbric epipedon 10 to 20 inches thick.
The A horizon has hue of 7.5YR or 10YR, value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It is gravelly, very gravelly or extremely gravelly loam. This horizon has moderate or strong granular or fine or very fine subangular blocky structure.
The Bw horizon has hue of 7.5YR or 10YR, value of 2, 3 or 4 moist, 4, 5 or 6 dry and chroma of 3 or 4 moist and dry. It is very cobbly loam, extremely gravelly or very gravelly loam with 20 to 50 percent gravel and 20 to 35 percent cobbles and less than 18 percent clay.
The C horizon has characteristics similar to the B horizon except for being massive and having 35 to 80 percent coarse fragments.
COMPETING SERIES: These are the
Harrington,
Klickitat,
Milbury,
Nordby,
Spivey,
Steever,
Summers and
Wauld series. Harrington soils have Bw horizons with more than 18 percent clay and hue redder than 7.5YR. Klickitat, Nordby and Spivey soils are deeper than 40 inches to bedrock. Milbury soils are very strongly or strongly acid. Summers soils; the series has not been revised and it is anticipated it will not be used in the future. Wauld soils average 18 to 30 percent clay in the particle-size control section.
GEOGRAPHIC SETTING: Brightwood soils are on smooth and dissected hill slopes in mountainous areas at elevations of 1,000 to 3,000 feet. Slopes range from 60 to 90 percent. The soils formed in very gravelly colluvium weathered from tuff and tuffaceous breccia bedrock. The climate is characterized by warm wet winters and hot moist summers. The mean annual precipitation is 80 to 95 inches. The mean annual temperature is 45 to 51 degrees F., the mean January temperature is about 34 degrees F., the mean July temperature is about 63 degrees F.. The frost-free season is 100 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Enola,
Hoodview and
Silcox soils. Enola and Silcox soils have influence of amorphous clays, are deeper than 40 inches to bedrock, and have less than 35 percent coarse fragments in the 10-to-40-inch control section. Hoodview soils are dominated by amorphous material in the particle-size control section.
DRAINAGE AND PERMEABILITY: Well drained; rapid runoff; moderately rapid permeability.
USE AND VEGETATION: Timber production, watershed, recreation, and wildlife. Overstory vegetation is mostly Douglas-fir, western hemlock, western redcedar, red alder, and bigleaf maple; understory vegetation is dominated by vine maple, swordfern and oxalis.
DISTRIBUTION AND EXTENT: Cascade Mountains in northwest Oregon. MLRA 3. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Clackamas County, Oregon, 1975.
REMARKS: Diagnostic horizons and other features:
Umbric epipedon - 1 to 11 inches
Cambic horizon - 11 to 19 inches
National Cooperative Soil Survey
U.S.A.