LOCATION WESTFIR OR
Tentative Series
IRD. DCR/MPR
02/2025
WESTFIR SERIES
Landscape--western Cascade mountains
Landform--mountain slopes, mountaintops
Slope--2 to 90 percent
Parent material--residuum weathered from tuff
Mean annual precipitation--about 1600 mm
Mean annual air temperature--about 9 degrees C
Depth class--moderately deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--mesic
Soil moisture subclass--typic
TAXONOMIC CLASS: Fine-loamy, isotic, mesic Typic Dystrudepts
TYPICAL PEDON: Westfir gravelly loam, on a south-facing mountain slope with a slope of 60 percent and an elevation of 664 m (All textures are apparent field textures).
Oi--0 to 4 cm; slightly decomposed plant material; abrupt wavy boundary
A--4 to 16 cm; gravelly loam, light brownish gray (10YR 6/2) dry, dark brown (10YR 3/3) moist; weak very fine granular structure; slightly sticky, slightly plastic; many medium and common very fine and coarse and few fine roots; many very fine interstitial pores; 25 percent gravel; moderately acid (pH 5.8); abrupt wavy boundary
Bw--16 to 48 cm; loam, light gray (10YR 7/2) dry, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly sticky, slightly plastic; common very fine and medium and few fine roots; many very fine dendritic tubular pores; 8 percent gravel; moderately acid (pH 5.7); clear smooth boundary
BC--48 to 88 cm; paragravelly loam, light gray (10YR 7/2) dry, brown (10YR 5/3) moist; weak coarse subangular blocky structure; moderately sticky, moderately plastic; common fine and medium and few very fine roots; common very fine dendritic tubular pores; 18 percent paragravel; moderately acid (pH 5.6); gradual wavy boundary
Cr--88 to 150 cm; paralithic bedrock, light gray (2.5Y 7/2) dry, olive (5Y 5/3) moist; massive; weakly coherent
TYPE LOCATION: Lane County, Oregon, about 14 km south of Nimrod in Willamette National Forest; 610 m south and 330 m east of the northwest corner of section 24, T. 18 S., R. 3 E., Willamette Meridian; latitude 43.99017, longitude -122.40230, datum WGS 84 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--8 to 11 degrees C
Depth to paralithic contact--50 to 100 cm
Volcanic glass content in the 0.02 to 2 mm fraction--less than 5 percent
Particle-size control section (weighted average)
*Clay content--18 to 27 percent
*Total rock fragments--5 to 35 percent
Oi horizon
*Combined thickness--0 to 6 cm
A horizon
*Value--3 or 4 moist, 6 or 7 dry
*Chroma--2 or 3 moist and dry
*Clay content--18 to 25 percent
*Sand content--30 to 50 percent
*Total fragment content--5 to 35 percent
*Gravel content--5 to 35 percent
*Cobble content--0 to 5 percent
*Reaction--pH 5.1 to 6.0
*Organic carbon content--1 to 3 percent
*Thickness--10 to 25 cm
Bw horizon
*Value--4 or 5 moist, 6 or 7 dry
*Chroma--2 to 4 moist and dry
*Fine-earth texture--loam, clay loam
*Clay content--18 to 30 percent
*Sand content--20 to 40 percent
*Total fragment content--0 to 15 percent
*Gravel content--0 to 15 percent
*Paragravel content--0 to 10 percent
*Cobble content--0 to 5 percent
*Reaction--pH 5.1 to 6.0
*Organic carbon content--0.6 to 2 percent
*Thickness--25 to 50 cm
BC horizon
*Hue--10YR or 2.5Y
*Value--4 or 5 moist, 6 or 7 dry
*Chroma--2 to 4 moist or dry
*Fine-earth texture--loam, clay loam, silty clay loam
*Clay content--22 to 35 percent
*Sand content--15 to 40 percent
*Total fragment content--5 to 35 percent
*Gravel content--0 to 15 percent
*Paragravel content--0 to 35 percent
*Cobble content--0 to 10 percent
*Reaction--5.1 to 6.0
*Organic carbon content--0.2 to 1 percent
COMPETING SERIES:
Bohemia--greater than 150 cm to bedrock
Skinner--100 to 150 cm to lithic contact
GEOGRAPHIC SETTING:
Elevation--240 to 910 m
Climate--warm, dry summers; mild, moist winters
Mean annual precipitation--1250 to 1900 mm
Mean annual air temperature--7 to 10 degrees C
Frost-free period--120 to 180 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Dutchoven--greater than 150 cm to bedrock, umbric epipedon; located on mountain slopes
Bohemia--greater than 150 cm to bedrock, ochric epipedon; located on mountain slopes
Goldcreek--xeric soil moisture regime, argillic horizon; located on south-facing mountain slopes
Norling--xeric soil moisture regime, 50 to 100 cm to paralithic contact; located on convex portions of south-facing mountain slopes
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--moderately high or moderately low
USE AND VEGETATION:
Use--timber production, recreation, wildlife habitat
Potential natural vegetation--Douglas-fir, western hemlock, sugar pine, giant chinquapin, Cascade barberry, salal, and twinflower; commonly supports a western hemlock/dwarf Oregon grape-salal-dry (CHS159) plant association (see Field Guide to the Forested Plant Associations of the Westside Central Cascades of Northwest Oregon)
DISTRIBUTION AND EXTENT: Central and southwestern Oregon Cascade Mountains, Oregon; MLRA 3; moderate extent
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Bozeman, Montana
SERIES PROPOSED: Willamette National Forest, Lane County, Oregon; 2022; name from town of Westfir, located several miles south of the type location
REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 29 to 88 cm
*Ochric epipedon
*Cambic horizon--zone from 16 to 88 cm
*Depth to paralithic contact--88 cm (weakly coherent)
*Typical pedon ID--2017OR039813
National Cooperative Soil Survey
U.S.A.