LOCATION COFFIN OR
Tentative Series
JGM/KMS
01/2017
COFFIN SERIES
Landscape--western Cascade Mountains
Landform--earthflows with some on complex landslides
Slope--0 to 30 percent
Parent material--earthflow deposits derived from igneous rock mixed with till and volcanic ash in upper part
Mean annual precipitation--about 2100 mm
Mean annual air temperature--about 7 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--frigid
Soil moisture subclass--typic
TAXONOMIC CLASS: Medial over loamy, amorphic over isotic, frigid Typic Hapludands
TYPICAL PEDON: Coffin gravelly medial loam on a southwest-facing, 20-percent slope of a forested complex landslide at an elevation of about 1050 m (The soil was moist throughout when described on September 10, 2014.)
Oi--0 to 10 cm; slightly decomposed plant material, very dark grayish brown (10YR 3/2) dry, very dark brown (10YR 2/2) moist; abrupt wavy boundary
A1--10 to 20 cm; gravelly medial loam, dark grayish brown (10YR 4/2) dry, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure and moderate very fine granular; slightly hard, very friable, nonsticky and slightly plastic; common very fine, fine, coarse, and very coarse and many medium roots; many very fine and common fine and medium tubular pores; 2 percent tuff paragravel, 13 percent tuff gravel, and 3 percent tuff cobbles; strongly acid (pH 5.4); clear wavy boundary
A2--20 to 65 cm; medial loam, dark grayish brown (10YR 4/2) dry, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure and moderate very fine granular; moderately hard, very friable, nonsticky and slightly plastic; few fine and common very fine, medium, and coarse roots; common fine and medium and many very fine tubular pores; 2 percent tuff paragravel, 6 percent tuff gravel, and 1 percent tuff cobbles; strongly acid (pH 5.2); clear wavy boundary
2Bw1--65 to 95 cm; silty clay loam, pale yellow (2.5Y 7/3) dry, olive brown (2.5Y 4/3) moist; moderate coarse subangular blocky structure; hard, friable, slightly sticky and very plastic; few fine and common very fine, medium, coarse, and very coarse roots; few fine and many very fine tubular pores; 4 percent tuff gravel; strongly acid (pH 5.2); gradual smooth boundary
2Bw2--95 to 150 cm; clay loam, pale yellow (2.5Y 8/3) dry, pale olive (5Y 6/4) moist; moderate coarse subangular blocky structure; hard, friable, slightly sticky and very plastic; few fine and common very fine roots; many very fine tubular pores; 4 percent tuff gravel; strongly acid (pH 5.4)
TYPE LOCATION: Linn County, Oregon, approximately 4000 m west of Pinnacle Peak, in Willamette National Forest; 480 m south and 75 m west of the northeast corner of section 27, T. 11 S., R. 5 E., Willamette Meridian; latitude 44.5918010, longitude -122.1758540, datum WGS 84 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--5 to 7 degrees C
Dry days--30 to 45 consecutive days following summer solstice
Thickness of umbric epipedon--50 to 100 cm
Depth to cambic horizon--50 to 100 cm below mineral soil surface
Reaction--5.0 to 6.0 throughout all mineral horizons
Thickness of andic soil properties--50 to 100 cm (below mineral soil surface)
Estimated properties of layers with andic soil properties
*1/3-bar bulk density--0.6 to 0.9 g/cm3
*Phosphate retention--greater than 85 percent
*Ammonium oxalate extractable Al + 1/2 Fe--2 to 4 percent
*15-bar water retention--30 to 70 percent (undried samples), greater than 15 percent (dried samples)
*0.02- to 2.0-mm fraction--greater than 30 percent
*Volcanic glass content in 0.02- to 2.0-mm fraction--5 to 30 percent
Particle-size control section
*Clay content--18 to 40 percent, weighted average less than 35 percent
*Total fragment content--0 to 35 percent
Oi horizon
*Thickness--5 to 10 cm
A horizon
*Value--2 to 3 moist, 3 to 5 dry
*Chroma--1 to 3 moist or dry
*Fine-earth texture--medial loam, medial silt loam
*Clay content--18 to 27 percent
*Sand content--25 to 45 percent
*Total fragment content--5 to 35 percent
*Gravel content--0 to 40 percent
*Paragravel content--0 to 5 percent
*Cobble content--0 to 5 percent
*Thickness--40 to 95 cm
2Bw1 horizon
*Hue--10YR, 2.5Y
*Value--4 to 6 moist, 5 to 7 dry
*Chroma--2 to 4 moist or dry
*Fine-earth texture--loam, clay loam, silty clay loam
*Clay content--25 to 35 percent
*Sand content--15 to 30 percent
*Total fragment content--0 to 35 percent
*Gravel content--0 to 25 percent
*Cobble content--0 to 10 percent
2Bw2 horizon
*Hue--10YR, 2.5Y, 5Y
*Value--4 to 6 moist, 5 to 8 dry
*Chroma--2 to 4 moist or dry
*Fine-earth texture--clay loam, silty clay loam
*Clay content--27 to 40 percent
*Sand content--15 to 30 percent
*Total fragment content--0 to 35 percent
*Gravel content--0 to 25 percent
*Cobble content--0 to 10 percent
Combined thickness of 2Bw horizon--50 to 100 cm
COMPETING SERIES:
Rugles--no umbric epipedon
GEOGRAPHIC SETTING:
Elevation--700 to 1100 m
Climate--warm, dry summers; cool, wet winters
Mean annual precipitation--1900 to 2300 mm
Mean annual air temperature--6 to 8 degrees C
Frost-free period--90 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Ramcreek--50 to 100 cm deep to aquic conditions; on similar landforms
Cadenza--andic soil properties less than 36 cm thick; more than 35 percent rock fragments; on steeper mountain slopes and short, steep slopes of complex landslides
Coolcamp--more than 35 percent rock fragments; on steeper mountain slopes and short, steep slopes of complex landslides
Husky--aquic conditions within 25 cm of surface; in sags of complex landslides
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Saturation in normal years--below a depth of 200 cm
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--rapid in A horizon; moderate to moderately slow in 2Bw horizon
USE AND VEGETATION:
Use--timber production, wildlife habitat, recreation
Potential natural vegetation--Douglas-fir, western hemlock, salal, dwarf Oregon grape, Pacific rhododendron, vine maple, red huckleberry, twinflower, western swordfern, Pacific trillium
DISTRIBUTION AND EXTENT: Western Cascade Mountains, Oregon; MLRA 3; small extent
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Willamette National Forest, Linn County, Oregon; 2016; name from Coffin Creek
REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 10 to 110 cm
*Umbric epipedon--zone from 10 to 65 cm
*Cambic horizon--zone from 65 to 150 cm
*Andic soil properties--zone from 10 to 65 cm
*Volcanic glass--zone from 10 to 65 cm
*Depth to lithologic discontinuity--65 cm
06/2016--Assumed to meet criteria 2 (no ash required) for andic soil properties, in the 12th edition of Keys to Soil Taxonomy. It is also assumed that enough ash is present for the soils to meet criteria 3. Additional lab data is needed to confirm the degree of ash influence. Samples should also be collected to determine if this series meets the criteria for the Alic Hapludand or Eutric Hapludand subgroup.
ADDITIONAL DATA: Type location user site ID--2014OR043819
National Cooperative Soil Survey
U.S.A.