LOCATION TUMBLEBUG OR
Tentative Series
IRD.DCR/MPR
02/2025
TUMBLEBUG SERIES
Landscape--southwestern Middle Cascade glaciated mountains
Landform--glacial-valley walls, cirque headwalls, cirque floors, mountaintops, colluvial aprons, complex landslides
Slope--0 to 90 percent
Parent material--pumice and volcanic ash over colluvium and till mixed with volcanic ash
Mean annual precipitation--about 1700 mm
Mean annual air temperature--about 5 degrees C
Depth class--very deep
Drainage class--well drained
Soil moisture regime--udic
Soil temperature regime--cryic
Soil moisture subclass--typic
TAXONOMIC CLASS: Pumiceous or ashy-pumiceous over medial, amorphic Typic Vitricryands
TYPICAL PEDON: Tumblebug paragravelly ashy coarse sandy loam, on an east-facing forested glacial-valley wall with a slope of 60 percent and an elevation of 1402 m
Oi--0 to 2 cm; slightly decomposed plant material; abrupt smooth boundary
Oe--2 to 5 cm; moderately decomposed plant material; abrupt smooth boundary
A--5 to 25 cm; paragravelly ashy coarse sandy loam, pale brown (10YR 6/3) dry, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; slightly hard, very friable, nonsticky, nonplastic; many very fine and common fine through coarse roots; many very fine irregular pores; 20 percent pumice paragravel; moderately acid (pH 5.6); clear smooth boundary
C--25 to 49 cm; very paragravelly ashy coarse sandy loam, pale brown (10YR 6/3) dry, dark yellowish brown (10YR 4/4) moist; single grain; loose, very friable, nonsticky, nonplastic; common very fine and medium and few coarse roots; many very fine interstitial pores; 55 percent pumice paragravel; slightly acid (pH 6.2); abrupt wavy boundary
2Bw1--49 to 96 cm; gravelly medial loam, light yellowish brown (10YR 6/4) dry, brown (7.5YR 4/4) moist; weak fine subangular blocky structure; slightly hard, very friable, nonsticky, slightly plastic; few medium and very fine roots; common very fine dendritic tubular pores; 15 percent gravel and 5 percent cobbles; moderately acid (pH 5.8); gradual smooth boundary
2Bw2--96 to 150 cm; cobbly medial loam, light yellowish brown (10YR 6/4) dry, brown (7.5YR 4/4) moist; weak fine subangular blocky structure; slightly hard, very friable, nonsticky, slightly plastic; few very fine roots; few very fine dendritic tubular pores; 15 percent gravel and 10 percent cobbles; moderately acid (pH 5.6)
TYPE LOCATION: Douglas County, Oregon, about 12 km northwest of Lemolo Lake, in Willamette National Forest; 80 m north and 180 m west of the southeast corner of section 22, T. 25 S., R. 4 E., Willamette Meridian; latitude 43.37958, longitude -122.31270, datum WGS 84 (coordinates determined with a GPS)
RANGE IN CHARACTERISTICS:
Mean annual soil temperature--4 to 8 degrees C
Thickness of andic soil properties--greater than 150 cm
Depth to lithologic discontinuity--36 to 60 cm below the mineral soil surface
Particle-size control section (upper part)
*Clay content--5 to 12 percent
*1/3-bar bulk density--0.5 to 0.9 g/cm3
*Phosphate retention--50 to less than 85 percent
*Ammonium oxalate Al plus 1/2 Fe--1 to 3 percent
*1500 kPa water (air-dried samples)--5 to 12 percent
*1500 kPa water (undried)--10 to 20 percent
*Volcanic glass content in 0.02 to 2.0 mm fraction--60 to 90 percent
Particle-size control section (lower part)
*Clay content--10 to 18 percent
*1/3-bar bulk density--0.8 to 1.1 g/cm3
*Phosphate retention--greater than 85 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
*Volcanic glass content in 0.02-to 2.0-mm fraction--20 to 60 percent
A horizon
*Hue--10YR or 7.5YR
*Value--3 to 5 moist, 5 or 6 dry
*Chroma--3 or 4 moist and dry
*Total fragment content--15 to 35 percent
*Pumice paragravel content--15 to 35 percent
*Gravel content--0 to 5 percent
*Cobble content--0 to 5 percent
*Reaction--pH 5.1 to 6.0
*Thickness--15 to 25 cm
C horizon
*Hue--10YR or 7.5YR
*Value--4 or 5 moist, 6 or 7 dry
*Chroma--3 or 4 moist or dry
*Total fragment content--35 to 60 percent
*Pumice paragravel content--35 to 60 percent
*Gravel content--0 to 5 percent
*Reaction--pH 5.6 to 6.5
*Thickness--15 to 40 cm
2Bw horizons
*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 loam, medial sandy loam
*Total fragment content--15 to 35 percent
*Gravel content--10 to 35 percent
*Cobble content--0 to 15 percent
*Stone content--0 to 5 percent
*Reaction--pH 5.6 to 6.5
COMPETING SERIES: None
GEOGRAPHIC SETTING:
Elevation--1225 to 1950 m
Climate--mild, dry summers; cold, wet winters
Mean annual precipitation--1500 to 1900 mm
Mean annual air temperature--3 to 7 degrees C
Frost-free period--45 to 105 days
GEOGRAPHICALLY ASSOCIATED SOILS:
Wilchutes--coarse-textured above the lithologic discontinuity, 100 to 150 cm to lithic contact; located on ice-scoured mountains and volcanic cones
Staleycreek--frigid soil temperature regime; located on colluvial aprons and glacial-valley walls
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained
Flooding--none
Ponding--none
Saturated hydraulic conductivity (Ksat)--high or very high in the upper part and high in the lower part
USE AND VEGETATION:
Use--recreation, wildlife habitat
Potential natural vegetation--mountain hemlock, Pacific silver fir, Pacific rhododendron, Cascade barberry, thinleaf huckleberry, common beargrass; commonly supports a Pacific silver fir/rhododendron/dwarf Oregon grape (CFS652) plant association (see Field Guide to the Forested Plant Associations of the Westside Central Cascades of Northwest Oregon)
DISTRIBUTION AND EXTENT: Southwestern Oregon 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 Tumblebug Creek near the type location.
REMARKS:
Diagnostic horizons and other features in this pedon
*Particle-size control section--zone from 5 to 105 cm
*Ochric epipedon
*Depth to lithologic discontinuity--49 cm
*Cambic horizon--zone from 49 to 150 cm
*Andic soil properties--zone from 5 to 150 cm
*Volcanic glass--zone from 5 to 150 cm
*Typical pedon ID--2020OR019867
National Cooperative Soil Survey
U.S.A.