LOCATION BOARDBURN CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Ultic Haploxeralfs
TYPICAL PEDON: Boardburn sandy loam on a northeast facing 16 percent slope under a cover of white fir, Ponderosa pine, sugar pine and black oak at an elevation of 4,540 feet. (Colors are for dry soil unless otherwise stated. When described October 19, 1983, the soil was dry throughout)
A1--0 to 4 inches; yellowish brown (10YR 5/4) sandy loam, very dark grayish brown (10YR 3/2) moist; strong fine granular structure; slightly hard, very friable, nonsticky and nonplastic; common very fine roots and few fine and medium roots; common very fine interstitial pores; 5 percent gravel; NaF pH 9.0; slightly acid (pH 6.1); abrupt smooth boundary.
A2--4 to 9 inches; brown (7.5YR 5/4) sandy loam, dark brown (7.5YR 3/4) moist; moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine and medium roots; common very fine interstitial and tubular pores; 5 percent gravel; NaF pH 9.0; slightly acid (pH 6.1); clear smooth boundary. (Combined thickness of the A horizon is 4 to 11 inches)
Bt1--9 to 15 inches; light brown (7.5YR 6/4) loam, dark brown (7.5YR 3/4) moist; moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and medium, and few coarse roots; common very fine interstitial and tubular pores; 5 percent gravel; NaF pH 8.5; slightly acid (pH 6.1); clear wavy boundary.
Bt2--15 to 22 inches; light brown (7.5YR 6/4) loam, brown (7.5YR 4/4) moist; strong fine angular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine and fine and few medium exped roots; common very fine tubular pores; common moderately thick clay films on peds and in pores; 5 percent gravel; NaF pH 8.5; slightly acid (pH 6.1); clear wavy boundary.
Bt3--22 to 40 inches; light brown (7.5YR 6/4) sandy clay loam, brown (7.5YR 4/4) moist; moderate medium angular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine and fine and few medium exped roots; common very fine tubular pores; common moderately thick clay films on peds and in pores; 10 percent gravel; NaF pH 8.0; slightly acid (pH 6.1); gradual wavy boundary. (Combined thickness of the Bt horizons is 25 to 35 inches)
2Bt--40 to 50 inches; reddish yellow (7.5YR 6/6) very gravelly sandy clay loam, brown (7.5YR 4/4) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; few fine and medium roots; common very fine tubular pores; common moderately thick clay films on peds and in pores; 45 percent gravel (tuff-basic), 5 percent cobbles; NaF pH 8.0; slightly acid (pH 6.1); clear irregular boundary. (10 to 15 inches thick)
2Cr--50 to 55 inches; weathered andesitic tuff easily dug with spade; identifiable rock structure with few roots.
TYPE LOCATION: Lassen County, California; about 8 miles northwest of Bieber on the east side of Big Valley Mountains 2,500 feet N and 1,000 feet W of the SE corner of sec. 14 T., 39 N., R. 6 E. Bieber NW (lookout) Quadrangle (7.5 minute series)
RANGE IN CHARACTERISTICS: Combined thickness of the A and Bt horizons and depth to paralithic contact ranges from 40 to 60 inches. The mean annual soil temperature is 47 to 52 degrees F. The soil temperature is above 41 degrees F. from mid March until late December and is above 47 degrees F. from early May until early December. The soil moisture control section is moist throughout from about early January until April for about 75 days and is dry throughout from about early July until mid October (110 to 130 days). The particle-size control section (9 to 29 inches) averages 27 to 35 percent clay, more than 45 percent sand, and 0 to 10 percent rock fragments, mostly gravel. Reaction is neutral or slightly acid.
The A horizon color is 10YR 5/3, 5/4; 7.5YR 4/4, 5/4, 6/4. Moist color is 10YR 3/2, 3/3, 3/4; 7.5YR 3/2, 3/4; or 5YR 3/4. Organic matter ranges from 1.1 to 4 percent. Clay content ranges from 15 to 20 percent. Rock fragments, mostly gravel range from 0 to 10 percent. NaF pH is 9.0 to 8.5. Base saturation by sum of cations ranges from 50 to 65 percent.
The Bt horizon color is 10YR 4/4; 7.5YR 5/4, 5/6, 4/6, 6/4. Moist color is 7.5YR 3/4, 4/4; 5YR 3/4. Clay content ranges from 25 to 35 percent. Rock fragments, mostly gravel range from 0 to 10 percent. Base saturation by sum of cations ranges from 65 to 75 percent.
The 2Bt horizon color is 7.5YR 5/6, 6/4, 6/6; 5YR 4/6. Moist color is 7.5YR 3/4, 4/4; 5YR 3/4, 4/4. Clay content ranges from 27 to 35 percent. Rock fragments, mostly gravel range from 35 to 60 percent. Base saturation by sum of cations ranges from 65 to 75 percent.
COMPETING SERIES: These are the Bernhill, Boomer, Casabonne, Cherryhill, Cle Elum, Cohasset, Crozier, Dalig (T), Fives, Fordcreek (T), Gunn (T), Holland, Hood, Hotaw, Latourell, Lettia, McGowan (T), Musick, Norling (T), Para (T), Rosehaven (T), Sanhedrin, Speaker, eanaway, Tigit (T), Trelk (T), Ulhalf (T), Underwood, Varelum, Wilkenson, and Wohly series. Cle Elum, Crozier, Hotaw, Norling, Speaker, Tigit, and Wohly soils are 20 to 40 inches deep to bedrock. Bernhill soils have a combined A and Bt thickness of more than 60 inches and are dry in the moisture control section for 60 to 90 days. Boomer, Casabonne, and Cohasset soils have mean annual soil temperatures of 54 to 59 degrees F. Fordcreek soils have 25 percent or less coarse fragments in all parts of the argillic horizon. Underwood and Wilkenson soils are dry in the moisture control section for 45 to 60 days and are trongly acid or moderately acid in the particle-size control section. Cherryhill soils have mean annual soil temperatures of 53 to 55 degrees F and are moderately acid. Dalig soils are moderately acid in the lower part of the Bt horizon and are dry in the moisture control section for 60 to 75 days. Fives soils are dry in the moisture control section for 45 to 90 days and are very strongly acid below 17 inches. Gunn soils are dry in the moisture control section for 60 to 75 days. Holland soils are moderately acid or strongly acid and have mean annual soil temperatures of 52 to 59 degrees F. Hood soils are dry in the moisture control section for 60 to 80 days and are moderately acid. Latourell soils are moderately acid or strongly acid, are dry in the moisture control section for 45 to 80 days and have mean annual soil temperatures of 54 to 56 degrees F. Lettia soils are dry in the moisture control section for 60 to 90 days. McGowen soils are dry in the moisture control section for 60 to 75 days and are moderately acid. Musick soils are moderately acid or strongly acid and have mean annual soil temperatures of 52 to 58 degrees F. Para soils are dry in the moisture control section for 60 to 75 days and have a base saturation of less than 60 percent in the Bt horizon. Rosehaven soils are moderately acid and have mean annual soil temperatures of 52 to 57 degrees F. Sanhedrin soils have mean annual soil temperatures of 52 to 57 degrees between 15 and 35 percent rock fragments in the particle size control section. Teanaway soils are dry in the moisture control section for 75 to 90 days and are moderately acid. Trelk soils have an argillic horizon less than 20 inches thick and are moderately acid. Ulhalf soils have 18 to 25 percent clay and greater than 15 percent rock fragments in the particle- size control section. Underwood and Wilkenson soils are dry in the moisture control section for 45 to 60 days and are moderately acid or strongly acid. Varelum soils range from 18 to 28 percent clay in the control section and are dry in the moisture control section for 60 to 80 days.
GEOGRAPHIC SETTING: Boardburn soils are on lava plateaus and hills. Slope is 5 to 50 percent. These soils formed in slope alluvium weathered from extrusive igneous rocks. Elevation is 4,000 to 4,800 feet. The climate is subhumid with warm dry summers and cold moist winters. Mean annual precipitation is 20 to 30 inches. Snowfall is 36 to 48 inches. The mean annual temperature is 45 to 48 degrees F. The mean January temperature is about 32 degrees F. The mean July temperature is about 65 degrees F. Frost-free period is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chirpchatter (T), Hambone (T), Hunsinger T), Roundbarn (T), and Rivalier (T) soils. Chirpchatter soils are fine-loamy and have a mollic epipedon. Hambone soils are loamy-skeletal. Hunsinger soils have a mollic epipedon. Roundbarn soils are frigid and have a mollic epipedon greater than 20 inches thick. Rivalier soils are frigid and moderately deep.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderately slow permeability.
USE AND VEGETATION: This soil is mainly used for timber production. The vegetation is mainly ponderosa pine, sugar pine, white fir, incense cedar, and greenleaf manzanita.
DISTRIBUTION AND EXTENT: Northeastern California. The soils are not extensive. MLRA 21
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lassen County, Intermountain Soil Survey Area, California, 1994. Source of name is coined.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from to 9 inches (A1, A2)
Argillic horizon - the zone from 9 to 50 inches (Bt1, Bt2, Bt3, 2Bt).
Paralithic contact - the boundary at 50 inches (2Cr).