LOCATION COLDTREE CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, isotic Xeric Haplocryalfs
TYPICAL PEDON: Coldtree very gravelly loamy coarse sand--forest land. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 55 percent gravel, 5 percent cobbles, and 1 percent stones.
A--0 to 1 inch; grayish brown (10YR 5/2) very gravelly loamy coarse sand, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many very fine interstitial pores; 50 percent gravel and 5 percent cobbles; very strongly acid; clear smooth boundary. (1 to 6 inches thick)
Bw/E1--1 to 4 inches; 60 percent pale brown (10YR 6/3) with 40 percent light brownish gray (10YR 6/2) extremely gravelly sandy loam, 60 percent brown (10YR 4/3) with 40 percent very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; many very fine and fine and common very coarse roots; many very fine interstitial and common very fine tubular pores; 60 percent gravel and 15 percent cobbles; very strongly acid, clear wavy boundary. (2 to 8 inches thick)
Bw/E2--4 to 9 inches; 80 percent very pale brown (10YR 7/3) with 20 percent light brownish gray (10YR 6/2) extremely gravelly sandy loam, 80 percent brown (10YR 5/3) with 20 percent brown (10YR 4/3) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine, fine, medium and coarse roots; many very fine interstitial and common very fine tubular pores; 60 percent gravel and 15 percent cobbles; very strongly acid; clear wavy boundary. (0 to 6 inches thick)
Bt1--9 to 17 inches; very pale brown (10YR 7/4) extremely gravelly sandy loam, yellowish brown (10YR 5/4) moist; moderate fine subangular blocky structure; soft, very friable, slightly sticky and nonplastic; common very fine, fine and medium roots; many very fine interstitial and common very fine tubular pores; few faint clay films on faces of peds and lining pores; 60 percent gravel and 15 percent cobbles; 10 percent paragravel; very strongly acid; clear wavy boundary. (6 to 9 inches thick)
Bt2--17 to 24 inches; very pale brown (10YR 7/4) extremely gravelly loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine and fine roots; many very fine interstitial and common very fine tubular pores; few faint clay films on faces of peds and lining pores; 60 percent gravel and 20 percent cobbles; 10 percent paragravel; very strongly acid; clear wavy boundary. (6 to 12 inches thick)
Bt3--24 to 44 inches; very pale brown (10YR 7/4) extremely cobbly loam, yellowish brown (10YR 5/4) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine and fine roots; many very fine interstitial and common very fine tubular pores; few faint clay films on faces of peds and lining pores; 55 percent gravel and 30 percent cobbles; 10 percent paragravel; very strongly acid; clear irregular boundary. (14 to 24 inches thick)
R--44 inches; hard fractured tuff.
TYPE LOCATION: Mono County, California; on the Toiyabe National Forest in the Sweetwater Mountains about 1.5 miles northwest of Mount Patterson; in the nonsectionized township T. 7 N., R. 24 E.; USGS Mount Patterson 7.5 minute topographic quadrangle; 38 degrees 26 minutes 51.0 seconds north latitude and 119 degrees 19 minutes 45.1 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in the moisture control section during late fall, winter, and spring; dry from July through early October for 60 to 80 consecutive days in the four months following the summer solstice; Typic xeric moisture regime.
Mean annual soil temperature - 35 to 40 degrees F.
Mean summer soil temperature - 44 to 47 degrees F.
Ochric epipedon thickness - 6 to 12 inches; includes the A and Bw/E horizons.
Depth to base of argillic horizon - 40 to 60 inches.
Depth to bedrock - 40 to 60 inches to a lithic contact.
Sodium fluoride pH - 9.5 to 11.5.
Particle-size control section - Clay content: Averages 10 to 18 percent; Rock fragments: Averages 60 to 85 percent, mainly gravel and cobbles. Lithology of fragments are volcanic rocks such as tuff.
A horizon - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 4 percent.
Reaction: Very strongly acid through moderately acid.
Bw/E horizons - Value: 5 through 7 dry, 4 or 5 moist.
Chroma: 2 or 3 dry, 2 through 4 moist.
Texture: Extremely gravelly sandy loam or extremely gravelly coarse sandy loam.
Clay content: 8 to 12 percent clay.
Rock fragments: 60 to 85 percent.
Reaction: Very strongly acid through moderately acid.
Bt horizons - Value: 6 or 7 dry, 4 or 5 moist.
Chroma: 4 or 6, dry or moist.
Texture: Extremely gravelly sandy loam, extremely gravelly loam, extremely cobbly loam, or extremely cobbly coarse sandy loam.
Clay content: 10 to 18 percent clay.
Rock fragments: 60 to 85 percent.
Reaction: Very strongly acid through moderately acid.
COMPETING SERIES: There are currently no other series in this family.
GEOGRAPHIC SETTING: Coldtree soils are on mountains. They typically occur on backslope and footslope positions. They formed in residuum and colluvium derived from tuff. Slopes are 30 to 75 percent. Elevations range from 9,500 to 11,500 feet. The climate is subhumid-continental with cold, moist winters and cool, dry summers. The mean annual precipitation is 20 to 30 inches, the mean annual temperature is 33 to 38 degrees F., and the frost-free period is less than 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Holdon, Mountpatterson, and Rolldown soils. Holdon soils have cambic horizons and fragmental material. Mountpatterson soils have mollic epipedons and are shallow to lithic contacts. Rolldown soils have mollic epipedons and are very deep.
DRAINAGE AND PERMEABILITY: Well drained; medium surface runoff; moderately rapid permeability (high saturated hydraulic conductivity).
USE AND VEGETATION: Coldtree soils are used for forest land, recreation, watershed, and wildlife habitat. The native vegetation is mainly a forest canopy of whitebark pine and limber pine with an sparse understory of bluegrass, sedge, and forbs.
DISTRIBUTION AND EXTENT: Eastern California, on the east side of the Sierra Nevada Range. These soils are not extensive with about 1,800 acres of the series mapped to date. MLRA 22A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Mono County (Toiyabe National Forest Area), California, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 9 inches (A, Bw/E1, and Bw/E2 horizons).
Albic horizon - The zone from 1 to 9 inches (Bw/E1 and Bw/E2 horizons).
Argillic horizon - The zone from 9 to 44 inches (Bt1, Bt2, and Bt3 horizons).
Lithic contact - The boundary at 44 inches to underlying hard bedrock (R layer).
Particle-size control section - The zone from 9 to 29 inches (Bt1 and Bt2 horizons and part of the Bt3 horizon).
The isotic mineralogy class is based on the field determined high values for sodium fluoride pH.