LOCATION BOARDTREE OREstablished Series
TAXONOMIC CLASS: Ashy over clayey, glassy over smectitic, frigid Alfic Vitrixerands
TYPICAL PEDON: Boardtree gravelly ashy loam, forest. (Colors are for moist soil unless otherwise noted.)
Oi--0 to 1 inch; slightly decomposed twigs, needles, leaves, cones, and grass. (0 to 2 inches thick)
A1--1 to 5 inches; very dark grayish brown (10YR 3/2) gravelly ashy loam, light brownish gray (10YR 6/2) dry; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine to medium roots; many very fine irregular pores; 25 percent gravel 2 to 10 mm in size; slightly acid (pH 6.3); gradual wavy boundary. (1 to 4 inches thick)
A2--5 to 10 inches; very dark grayish brown (10YR 3/2) gravelly ashy loam, light brownish gray (10YR 6/2) dry; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine irregular pores; 25 percent gravel 2 to 10 mm in size; slightly acid (pH 6.3); gradual wavy boundary. (4 to 15 inches thick)
Bw--10 to 17 inches; dark grayish brown (10YR 4/2) gravelly ashy loam, pale brown (10YR 6/3) dry; weak very fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many fine to coarse roots; many very fine tubular pores; 25 percent gravel 2 to 10 mm in size; slightly acid (pH 6.3); gradual wavy boundary. (4 to 10 inches thick)
C--17 to 32 inches; grayish brown (10YR 5/2) gravelly ashy loam, pale brown (10YR 6/3) dry; massive; slightly hard, friable, slightly sticky and slightly plastic; many fine to coarse roots; many very fine irregular pores; 30 percent gravel 2 mm to 1 inch in size; few fragments of clay 2 to 6 inches in size; slightly acid (pH 6.4); abrupt wavy boundary. (0 to 16 inches thick)
2Btb--32 to 61 inches; dark brown (10YR 3/3) gravelly clay, brown (10YR 5/3) dry; moderate medium subangular blocky structure; hard, firm, very sticky and very plastic; few fine and medium roots; many very fine and fine tubular pores; 15 percent gravel 2 mm to 1 inch in size; many faint very dark grayish brown (10YR 3/2) clay films on peds and in pores; bleached silt coatings on surfaces of peds in upper 2 inches; neutral (pH 6.6).
TYPE LOCATION: Jefferson County, Oregon; 100 feet south of road in the SE1/4 NE1/4 SW1/4 sec. 25, T.11S., R.16E.
RANGE IN CHARACTERISTICS: Moist bulk density of 0.75 to 0.85 g/cubic centimeter and contain 60 to 70 percent glass and glass aggregate in the ash overlay. The mean annual soil temperature is 42 to 47 degrees F. The mean summer soil temperature is greater than 60 degrees F. The soils are usually moist but are dry in all parts between depths of 8 and 24 inches for 60 to 90 consecutive days within the 3 months following the summer solstice. Thickness of the ashy materials and depth to contrasting clayey materials range from 20 to 40 inches. Bedrock commonly is deeper than 60 inches. Rock fragments greater than 2mm in size range from 0 to 30 percent within the control section. Cobbles and stones commonly are absent but may range to 5 percent in some pedons. The soil is slightly acid to neutral.
The A horizon has value of 3 or 4 moist, 5 or 6 dry, and chroma of 1 or 2 moist and dry. It is gravelly loam, loam, or silt loam with 10 to 20 percent clay. It has 0 to 30 percent gravel and 0 to 5 percent cobbles or stones. Organic matter is 2 to 4 percent.
The Bw horizon has hue of 10YR or 7.5YR, value of 4 or 5 moist, 6 or 7 dry, and chroma of 2 or 3 moist and dry. It is gravelly loam, loam, or silt loam with 10 to 20 percent clay. It has 0 to 30 percent gravel and 0 to 5 percent cobbles or stones.
The C horizon has characteristics similar to the Bw horizon and is absent in some pedons.
The 2Btb horizon has hue of 10YR or 7.5YR, value of 3 or 4 moist, 4 to 6 dry, and chroma of 3 or 4 moist and dry. It is clay, silty clay, clay loam, or silty clay loam with 35 to 50 percent clay and 5 to 15 percent gravel and 0 to 15 percent cobbles.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: They formed in volcanic ash and mixed loess over older clayey colluvium. They are in mountains at elevations of 3,000 to 5,000 feet. The climate is characterized by cold and wet winters and hot and dry summers. The mean annual precipitation is 16 to 25 inches. The mean annual temperature is 40 to 45 degrees F. The mean summer temperature is 56 to 60 degrees F. The mean winter temperature is 25 to 30 degrees F. The frost-free period (32 degrees F.) is 10 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hankins, Tolo, and Yawkey soils. Hankins soils lack the ashy overlay and have cobbly clay argillic horizons. Tolo soils have ash over argillic horizons with less than 35 percent clay. Yawkey soils have more than 35 percent rock fragments in the control section and have less than 60 percent ash in the solum.
DRAINAGE AND PERMEABILITY: Well-drained; medium to rapid runoff; moderately rapid permeability in the ash and very slow in the clayey materials.
USE AND VEGETATION: These soils are used for timber production, recreation, wildlife, and water supply purposes. Native plants are Douglas fir, ponderosa pine, Idaho fescue, pinegrass and elk sedge.
DISTRIBUTION AND EXTENT: Central Oregon. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Jefferson County (Trout Creek-Shaniko Area), Oregon, 1970.
REMARKS: Diagnostic horizons and features in this pedon include:
Ochric epipedon
Cambic horizon - from 10 to 17 inches (Bw horizon)
Argillic horizon - from 32 to 60 inches (2Btb horizon)
Vitrixerand feature - from 1 to 32 inches (A1, A2, Bw, C horizons) having more than 60 percent volcanic glass and glass aggregate, more than 0.4 percent acid oxalate Al + 1/2 Fe, and less than 12 percent 15-bar moisture content (dry).
Particle-size control section - from 1 to 41 inches.
Ranges of properties in the ash material is based on laboratory data from the similar associated Tolo soil (S60-OR-31-1 and 2, and reference samples 86T7089 and 86T7090).