LOCATION HIDDENRIDGE WA

Established Series
Rev. MPR/TMR/SBC
06/2011

HIDDENRIDGE SERIES

The Hiddenridge series consists of deep, well drained soils formed in glacial drift mixed with colluvium from metasedimentary bedrock. Hiddenridge soils are on hillslopes and mountain slopes at elevations near sea level to 2,200 feet. Slopes are 8 to 75 percent. Mean annual precipitation is about 26 inches. Mean annual temperature is about 50 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, isotic, mesic Pachic Humixerepts

TYPICAL PEDON: Hiddenridge gravelly coarse sandy loam - forested, on a south-facing mountain slope with a slope of 60 percent and elevation of 1,400 feet. When described on November 13, 2002 the soil was moist to 4 inches and dry below. Colors are for moist soil unless otherwise noted.

Oi--0 to 1 inch, slightly decomposed plant material; very strongly acid (pH 4.5); abrupt smooth boundary. (1 to 2 inches thick)

A1--1 to 3 inches, very dark brown (10YR 2/2) gravelly coarse sandy loam, very dark grayish brown (10YR 3/2) dry; weak fine subangular blocky structure; soft, very friable, non-sticky and non-plastic; common very fine to medium roots; many very fine and fine irregular and interstitial pores; 20 percent gravel; strongly acid (pH 5.5); abrupt smooth boundary.

A2--3 to 24 inches, very dark grayish brown (10YR 3/2) very gravelly coarse sandy loam, dark grayish brown (10YR 4/2) dry; weak medium subangular blocky structure; slightly hard, friable, non-sticky and non-plastic; common fine to coarse roots; many very fine and fine irregular and interstitial pores; 40 percent gravel; strongly acid (pH 5.2); clear wavy boundary. (Combined thickness of the A horizon is 10 to 24 inches)

C--24 to 57 inches, very dark grayish brown (2.5Y 3/2) extremely gravelly coarse sandy loam, olive brown (2.5Y 4/3) dry; single grain; loose, non-sticky and non-plastic; common very fine to medium, few coarse roots; many very fine and fine irregular and many fine to coarse interstitial pores; 75 percent gravel and 5 percent cobbles; strongly acid (pH 5.3); clear wavy boundary. (16 to 35 inches thick)

R--57 inches, fractured metasedimentary bedrock.

TYPE LOCATION: San Juan County, Washington, about 4 miles southeast of the town of Eastsound; about 600 feet south and 1,800 feet west of the northeast corner of section 32, T. 37 N., R. 1 W. Willamette Baseline Meridian; USGS Mount Constitution SW quarter quadrangle; Latitude 48 degrees 39 minutes 29 seconds North, Longitude 122 degrees 50 minutes 37 seconds West.

RANGE IN CHARACTERISTICS: Depths to diagnostic horizons and features start from the mineral soil surface.

Mean annual soil temperature - 50 to 54 degrees F.
Soil moisture control section - dry 75 to 90 days following summer solstice
Umbric epipedon thickness - 20 to 24 inches
Base saturation by ammonium acetate less than 50 percent from the soil surface to the top of a lithic contact
Depth to lithic contact - 40 to 60 inches
Reaction - moderately or strongly acid
Volcanic glass: less than 5 percent throughout
Particle size control section:
Clay content - 0 to 18 percent
Rock fragments - 25 to 80 percent gravel, 0 to 10 percent cobbles, 35 to 85 percent total

A1 horizon
Hue - 10YR to 7.5YR
Value - 2 or 3 moist, 3 or 4 dry
Chroma - 1 or 2 moist and dry
Clay content - 5 to 18 percent
Rock fragments - 15 to 30 percent gravel

A2 horizon
Hue - 10YR to 7.5YR
Value - 2 or 3 moist, 3 or 4 dry
Chroma - 1 or 2 moist and dry
Texture - L, SL, COSL
Clay content - 5 to 18 percent
Rock fragments - 15 to 60 percent gravel

C horizon
Hue 2.5Y to 10YR
Value - 3 or 4 moist, 4 or 5 dry
Chroma - 2 or 3 moist and dry
Texture - SL, COSL
Clay content - 0 to 18 percent
Rock fragments - 35 to 80 percent gravel, 0 to 10 percent cobbles, 35 to 85
percent total

COMPETING SERIES: There are no competing series in this family. Series with similar classification but mixed mineralogy include the Airstrip, Coyata, Decy, Musty, Tyson, Wyeth, and Zeibright soils. Airstrip, Coyata, Decy, Masterson, Musty, and Tyson soils have a lithic contact at 20 to 40 inches. Fiddletown soils have a paralithic contact at 24 and 48 inches. Wyeth soils have more than 18 percent clay in the particle-size control section. Zeibright soils have a frost-free period of 100 to 150 days.

GEOGRAPHIC SETTING: Hiddenridge soils are on south-facing hillslopes and mountain slopes with slopes of 8 to 75 percent and elevations from 0 to 2,200 feet. These soils formed in glacial drift mixed with colluvium from metasedimentary bedrock. The maritime climate is characterized by warm dry summers and mild moist winters. Mean annual precipitation is 18 to 35 inches. Mean annual air temperature is 48 to 52 degrees F. The frost-free period is 200 to 240 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cady, Doebay, Haro, and Turtleback soils, all of which also occur on hillslopes and mountain slopes. Cady soils have a lithic contact within 20 inches, an ochric epipedon, and generally occur under a denser forest canopy on northerly slopes. Doebay soils have a lithic contact at 20 to 40 inches, an ochric epipedon, and generally occur under a denser forest canopy on northerly slopes. Haro soils have a lithic contact within 20 inches and a mollic epipedon. Turtleback soils have an ochric epipedon and a cambic horizon.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained. Saturated hydraulic conductivity is high to very high.

USE AND VEGETATION: These soils are used for livestock grazing, home sites, recreation, watershed, and wildlife habitat. Potential natural vegetation consists of an overstory of scattered Douglas-fir, Pacific madrone, and Oregon white oak. Understory consists of baldhip rose, Roemers fescue, western brackenfern, trailing blackberry, common snowberry, Oregongrape, and oceanspray.

DISTRIBUTION AND EXTENT: Northwest Washington; MLRA 2, Northern Part. Series is of small extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon

SERIES ESTABLISHED: San Juan County, Washington, 2006.

REMARKS: Diagnostic horizons and features recognized in this pedon include:
Umbric epipedon - the zone from 1 to 24 inches (A horizons)
Lithic contact - 57 inches (R horizon)
Particle-size control section - the zone from 10 to 40 inches
The series was orginally defined to have a epipedon thickness of 10 to 24 inches. The typical pedon is over 20 inches thick thus Pachic subgroup. The series was orginally classified as Humic Dystroxerepts.

ADDITIONAL DATA: One reference pedon sampled at the type location, NSSL pedon # 03N0238, NASIS user pedon ID 02WA-055-004.

National Cooperative Soil Survey
U.S.A.