LOCATION WILCHUTES OR
Tentative Series
IRD. DCR/MPR
02/2025
WILCHUTES SERIES
Landscape--Mazama High Cascade mountains
Landform--ice-scoured mountains, volcanic cones
Slope--0 to 60 percent
Parent material--pumice and coarse volcanic ash over residuum or till mixed with volcanic ash over basalt or andesite bedrock
Mean annual precipitation--about 1600 mm
Mean annual air temperature--about 4 degrees C
Depth class--deep to bedrock
Drainage class--somewhat excessively drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Pumiceous or ashy-pumiceous over medial-skeletal, amorphic Andic Haplocryods
TYPICAL PEDON: Wilchutes paragravelly loamy coarse sand, on a forested structural bench with a slope of 10 percent and an elevation of 1738 m (All textures are apparent field textures).
Oi--0 to 1 cm; slightly decomposed plant material; abrupt smooth boundary
Oe--1 to 4 cm; moderately decomposed plant material, black (10YR 2/1) dry, black (10YR 2/1) moist; common very fine and few fine and common medium roots; abrupt wavy boundary
E--4 to 5 cm; paragravelly loamy coarse sand, light gray (10YR 7/2) dry, grayish brown (10YR 5/2) moist; weak fine subangular blocky structure; soft, very friable, nonsticky, nonplastic; common very fine, fine, and medium roots; many very fine interstitial pores; 30 percent pumice paragravel; very strongly acid (pH 4.8); abrupt wavy boundary
Bs --5 to 24 cm; paragravelly ashy loamy coarse sand, light brown (7.5YR 6/3) dry, brown (7.5YR 4/3) moist; weak medium subangular blocky structure; soft, very friable, nonsticky, nonplastic; common very fine, fine, medium, coarse, and very coarse roots; many very fine interstitial pores; 30 percent pumice paragravel; moderately acid (pH 5.7); clear smooth boundary
C--24 to 88 cm; extremely paragravelly ashy coarse sand, very pale brown (10YR 7/3) dry, yellowish brown (10YR 5/4) moist; single grain; loose, nonsticky, nonplastic; few medium and coarse roots; many fine interstitial pores; 70 percent pumice paragravel; slightly acid (pH 6.2); abrupt wavy boundary
2Bw--88 to 132 cm; very stony medial fine sandy loam, brown (7.5YR 5/3) dry, dark brown (7.5YR 3/3) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky, slightly plastic; few medium and coarse roots; common very fine dendritic tubular pores; 5 percent basalt cobbles, 30 percent basalt stones, and 10 percent basalt boulders; slightly acid (pH 6.3); abrupt wavy boundary
2R--132 cm; indurated vesicular basalt
TYPE LOCATION: Douglas County, Oregon, about 1 km south of Summit Lake in Willamette National Forest; 640 m north and 600 m west of the southeast corner of section 4, T. 25 S., R. 5 1/2 E., Willamette Meridian; latitude 43.434570, longitude -122.12830 , datum WGS 84 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 to 6 degrees C
Depth to lithic contact--100 to 150 cm
Depth to lithologic discontinuity--50 to 85 cm below the mineral soil surface
Particle-size control section (upper part)
*Clay content--0 to 5 percent
*Volcanic glass content in 0.02 to 2.0 mm fraction--60 to 90 percent
*Fine-earth fraction--contains more than 50 percent medium through very coarse sand
*1500 kPa water (air-dried samples)--5 to 12 percent
*1500 kPa water (undried)--10 to 20 percent
*1/3-bar bulk density--0.5 to 0.9 g/cm3
Particle-size control section (lower part)
*Clay content--2 to 10 percent
*1/3-bar bulk density--0.8 to 1.1 g/cm3
*Phosphate retention--85 to 100 percent
*Ammonium oxalate Al plus 1/2 Fe--2 to 4 percent
*1500 kPa water (air-dried samples)--greater than 15 percent
*1500 kPa water (undried)--20 to 30 percent
*Particles 0.02 to 2.0 mm diameter--greater than 30 percent of the fine-earth fraction
*Volcanic glass content in 0.02 to 2.0 mm fraction--30 to 60 percent
O horizons
*Composition--slightly to moderately decomposed plant material
*Combined thickness--0 to 10 cm
E horizon
*Value--4 or 5 moist, 6 or 7 dry
*Chroma--1 or 2 moist and dry
*Clay content--0 to 5 percent
*Total fragment content--15 to 35 percent
*Pumice paragravel content--15 to 35 percent
*Gravel content--0 to 5 percent
*Reaction--pH 4.5 to 5.0
*Phosphate retention--less than 25 percent
*Ammonium oxalate Al plus 1/2 Fe--less than 1 percent
*Thickness--1 to 5 cm
Bs horizon
*Value--3 to 5 moist, 5 or 6 dry
*Chroma--3 or 4 moist and dry
*Total fragment content--25 to 50 percent
*Pumice paragravel content--25 to 50 percent
*Gravel content--0 to 5 percent
*Reaction--pH 5.1 to 5.9
*Phosphate retention--50 to less than 85 percent
*Ammonium oxalate Al plus 1/2 Fe--1 to 3 percent
*Thickness--5 to 25 cm
C horizon
*Value--4 or 5 moist, 6 or 7 dry
*Chroma--3 or 4 moist or dry
*Pumice paragravel content--35 to 80 percent
*Reaction--pH 6.1 to 6.5
*Phosphate retention--50 to less than 85 percent
*Ammonium oxalate Al plus 1/2 Fe--1 to 3 percent
*Thickness--30 to 70 cm
2Bw horizon
*Hue--10YR or 7.5YR
*Value--3 or 4 moist, 5 or 6 dry
*Chroma--3 or 4 moist or dry
*Fine-earth texture--medial fine sandy loam, medial sandy loam
*Clay content--2 to 10 percent
*Total fragment content--35 to 60 percent
*Gravel content--0 to 10 percent
*Cobble content--5 to 15 percent
*Stone content--15 to 40 percent
*Boulder content--0 to 15 percent
*Reaction--pH 6.1 to 6.5
*Thickness--25 to 70 cm
COMPETING SERIES:
Lostwagon--greater than 150 cm to bedrock
GEOGRAPHIC SETTING:
Elevation--1525 to 2050 m
Climate--cool, dry summers; cold, wet winters
Mean annual precipitation--1400 to 1900 mm
Mean annual air temperature--3 to 5 degrees C
Frost-free period--30 to 60 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Waldor--50 to 75 cm to redox concentrations; located on glaciated mountains
Lostwagon--greater than 150 cm to bedrock; located on glacial-valley floors, moraines, glacial-valley walls, and cirque headwalls
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--somewhat excessively drained
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--very high in the upper part and high in the lower part
USE AND VEGETATION:
Use--recreation, wildlife habitat
Potential natural vegetation--mountain hemlock, grouse whortleberry, pipsissewa, thinleaf huckleberry; commonly supports a mountain hemlock/grouse whortleberry (CMS118) plant association (see Field Guide to the Forested Plant Associations of the Westside Central Cascades of Northwest Oregon)
DISTRIBUTION AND EXTENT: Mazama High Cascade Mountains, Oregon; MLRA 3; moderate extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Willamette National Forest, Douglas County, Oregon; 2022; name from the Willamette-Deschutes river divide
REMARKS:
Diagnostic horizons and other features in this pedon:
*Particle-size control section--zone from 29 to 104 cm
*Albic horizon--4 to 5 cm
*Spodic horizon--5 to 24 cm
*Andic soil properties--zone from 5 to 132 cm
*Volcanic glass--zone from 4 to 132 cm
*Depth to lithologic discontinuity--88 cm
*Depth to lithic contact--132 cm
*Typical pedon ID--2020OR019809
National Cooperative Soil Survey
U.S.A.