LOCATION CASCADIA OR
Tentative Series
JGM/DCR/MPR
12/2024
CASCADIA SERIES
Landscape--western Cascade Mountains
Landform--mountain slopes, structural benches
Slope--2 to 90 percent
Parent material--colluvium and residuum derived from volcanic rocks
Mean annual precipitation--about 1700 mm
Mean annual air temperature--about 9 degrees C
Depth class--moderately deep to lithic contact
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--mesic
Soil moisture subclass--typic
TAXONOMIC CLASS: Loamy-skeletal, isotic, mesic Andic Humudepts
TYPICAL PEDON: Cascadia gravelly silt loam on a forested, northwest-facing, 45-percent slope at an elevation of 675 m (The soil was dry throughout when described on August 1, 2013.)
Oi--0 to 4 cm; slightly decomposed plant material
A--4 to 14 cm; gravelly silt loam, brown (7.5YR 4/2) dry, very dark brown (7.5YR 2.5/2) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine to very coarse roots; many fine irregular and tubular pores; 30 percent gravel; strongly acid (pH 5.3); gradual smooth boundary
AB--14 to 37 cm; very cobbly silt loam, brown (7.5YR 4/3) dry, very dark brown (7.5YR 2.5/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine to medium and common coarse and very coarse roots; many fine irregular tubular pores; 20 percent gravel and 20 percent cobbles; strongly acid (pH 5.4); clear wavy boundary
Bw1--37 to 70 cm; very cobbly silt loam, brown (7.5YR 4/3) dry, dark brown (7.5YR 3/4) moist; weak fine subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; many very fine and fine and common medium to very coarse roots; many fine irregular tubular pores; 20 percent gravel and 35 percent cobbles; moderately acid (pH 5.6); gradual wavy boundary
Bw2--70 to 94 cm; extremely cobbly silt loam, brown (7.5YR 4/4) dry, dark brown (7.5YR 3/4) moist; weak fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine to very coarse roots; many fine irregular pores and common fine tubular pores; 20 percent gravel and 50 percent cobbles; moderately acid (pH 5.8); clear wavy boundary
R--94 cm; very strongly cemented andesite
TYPE LOCATION: Linn County, Oregon, about 7.5 km north of Blue River Reservoir, in Willamette National Forest; 225 m north and 625 m east of the southwest corner of section 8, T. 15 S., R. 5 E.; latitude 44.2702327, longitude -122.2396533, datum NAD 83 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--8 to 11 degrees C
Thickness of umbric epipedon--25 to 50 cm
Thickness of cambic horizon--25 to 75 cm
Depth to lithic contact--50 to 100 cm below mineral soil surface
Hue--10YR, 7.5YR
Reaction--pH 5.1 to 6.0
Properties of layers meeting andic subgroup criteria
*1/3-bar bulk density--0.70 to 1.0 g/cm3
*Phosphate retention--50 to 100 percent
*Ammonium oxalate Al plus 1/2 Fe--1 to 2 percent
*Volcanic glass content in the coarse silt fraction--5 to 10 percent
*Thickness--18 to 50 cm
Particle-size control section (weighted average)
*Clay content--18 to 27 percent
*Total fragment content--35 to 75 percent
Oi horizon
*Thickness--0 to 6 cm
A and AB horizons
*Value--2 to 3 moist, 3 to 5 dry
*Chroma--2 or 3 moist or dry
*Fine-earth texture--silt loam, loam
*Clay content--18 to 27 percent
*Sand content--20 to 50 percent
*Total fragment content--15 to 50 percent
*Gravel content--15 to 35 percent
*Cobble content--0 to 15 percent
*Combined thickness--18 to 36 cm
Bw horizons
*Value--3 or 4 moist, 4 to 6 dry
*Chroma--3 to 6 moist or dry
*Fine-earth texture--silt loam, loam
*Clay content--18 to 27 percent
*Sand content--20 to 50 percent
*Total fragment content--35 to 75 percent
*Gravel content--15 to 40 percent
*Cobble content--20 to 60 percent
*Stone content--0 to 10 percent
*Combined thickness--25 to 75 cm
COMPETING SERIES:
Aschoff--depth to bedrock is greater than 150 cm
Hoodview--depth to bedrock is greater than 150 cm
Nordby--depth to bedrock is greater than 150 cm
Damewood--thickness of the umbric epipedon is 50 to 100 cm
GEOGRAPHIC SETTING:
Elevation--240 to 910 m
Climate--mild, wet winters; warm, dry summers
Mean annual precipitation--1500 to 1900 mm
Mean annual air temperature--7 to 10 degrees C
Frost-free period--120 to 180 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Aschoff--greater than 150 cm deep to bedrock; located on concave and linear portions of mountain slopes
Kinney--less than 35 percent fragments in the particle-size control section; located on complex landslides and linear portions of mountain slopes
Mooseridge--50 to 100 cm to aquic conditions; located on complex landslides
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturation in normal years--none
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--high
USE AND VEGETATION:
Use--timber production, watershed, recreation, wildlife habitat
Potential natural vegetation--Douglas-fir, western hemlock, salal, Cascade barberry, western swordfern, twinflower, vine maple, red huckleberry, California blackberry
DISTRIBUTION AND EXTENT: Cascade Mountains in northwest Oregon; MLRA 3; small extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Linn County, Oregon; 2016; name from local campground
REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 29 to 94 cm
*Umbric epipedon--zone from 4 to 37 cm
*Andic subgroup feature--zone from 4 to 37 cm
*Cambic horizon--zone from 37 to 94 cm
*Depth to lithic contact--94 cm
5/2023--Laboratory data for geographically associated soils supports andic subgroup criteria in the 13th edition of Keys to Soil Taxonomy.
ADDITIONAL DATA: Type location user site ID--2013OR043434
National Cooperative Soil Survey
U.S.A.