LOCATION UMAK OREstablished Series
TAXONOMIC CLASS: Ashy-pumiceous, amorphic Typic Vitricryands
TYPICAL PEDON: Umak paragravelly ashy fine sandy loam, on a 2 percent slope, forest. (Colors are for moist soils unless otherwise noted. Described by T. Clark, 9/16/99.)
Oi--0 to 1 inch; slightly decomposed organic material with 20 percent pumice paragravel and 10 pumice paracobbles; abrupt wavy boundary. (1 to 2 inches thick)
A--1 to 5 inches; very dark grayish brown (10YR 3/2) paragravelly ashy fine sandy loam, brown (10YR 5/3) dry; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine and fine and few medium roots; many very fine interstitial pores; 20 percent pumice paragravel and 5 percent pumice paracobbles; moderately acid (pH 6.0); clear wavy boundary. (3 to 14 inches thick)
Bw1--5 to 21 inches; brown (10YR 4/3) very paracobbly ashy coarse sandy loam, very pale brown (10YR 7/4) dry; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and fine and few medium roots; common very fine interstitial pores; 20 percent pumice pragravel and 30 percent pumice paracobbles; slightly acid (pH 6.2); clear wavy boundary. (11 to 20 inches thick)
Bw2--21 to 43 inches; brown (7.5YR 4/4) extremely paracobbly ashy loamy coarse sand, light brown (7.5YR 6/4) dry; weak fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few fine and medium roots; few very fine interstitial pores; 30 percent pumice paragravel, 30 percent pumice pracobbles, and 10 percent pumice parastones; slightly acid (pH 6.4); clear wavy boundary. (15 to 30 inches thick)
Bw3--43 to 62 inches; brown (7.5YR 4/4) extremely paracobbly ashy loamy coarse sand, pinkish gray (7.5YR 6/2) dry; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; 40 percent pumice paragravel, 20 percent pumice paracobbles, 10 percent cinder cobbles, and 10 percent pumice parastones; neutral (pH 6.6).
TYPE LOCATION: Klamath County, Oregon, Crater Lake National Park; about 2.5 miles east of the west boundary of Crater Lake National Park on Hwy 62 and about 100 feet north of the road; UTM Zone 10, 561949 easting, 4748630 northing, NAD 83 (GPS). Latitude - 42 degrees, 53 minutes, 16 seconds North; Longitude - 122 degrees, 14 minutes, 29 seconds West.
RANGE IN CHARACTERISTICS: The average annual soil temperature ranges from 39 to 43 degrees F. The soils are usually moist but are dry in all parts of the moisture control section for 30 to 45 consecutive days following the summer solstice. Andic soil properties are present throughout a thickness of 14 to 30 inches and have 60 to 90 percent volcanic glass, 1.0 to 2.5 acid oxalate extractable aluminum plus one-half iron, 50 to 85 percent phosphate retention, 3 to 12 percent 15-bar air-dry moisture content and 4 to 13 percent moist 15-bar water content. The weighted average of 8xSi+2Xfe is 5 to 8. The particle-size control section averages 35 to 80 percent pumice fragments.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 2 or 3 moist and dry. It contains 10 to 30 percent pumice paragravel, 0 to 10 percent cinder gravel, 0 to 5 percent andesite gravel, and 0 to 10 percent pumice paracobbles.
The Bw1 horizon has value of 3 or 4 moist, 5 through 7 dry and chroma of 3 or 4 moist and dry. It is ashy coarse sandy loam or ashy sandy loam. It contains 10 to 45 percent pumice paragravel, 0 to 10 percent cinder gravel, 5 to 30 percent pumice paracobbles, and 0 to 10 percent pumice parastones.
The Bw2 and Bw3 horizons have hue of 7.5YR or 10YR, value of 3 or 4 moist, 4 or 5 dry, and chroma of 2 through 4 moist and dry. It is ashy loamy coarse sand or ashy loamy sand. It contains 10 to 50 percent pumice paragravel, 0 to 5 percent andesite gravel, 15 to 50 percent pumice paracobbles, 0 to 10 percent cinder cobbles, and 0 to 10 percent pumice parastones.
COMPETING SERIES: This is the Timbercrater series. Timbercrater soils are dominated by paragravel size fragments and formed in eolian material.
GEOGRAPHIC SETTING: Umak soils are on ash flows at elevations of 4,500 to 7,000 feet. Slopes range from 0 to 15 percent. The soils formed in pumice and ash flow deposits from Mt. Mazama. The climate is characterized by cold wet winters and cool moist summers. The mean annual precipitation is 40 to 70 inches, falling mostly as snow. The mean annual temperature is 38 to 42 degrees F and the frost-free period is 0 to 50 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Castlecrest, Llaorock, Unionpeak and the competing Timbercrater series. Castlecrest and Unionpeak are ashy. Llaorock is ashy-skeletal and on adjacent ridges.
DRAINAGE AND PERMEABILITY: Excessively drained; runoff is moderate. Permeability is very rapid.
USE AND VEGETATION: These soils are used for woodland, wildlife habitat, and recreation purposes. Vegetation is mountain hemlock, Shasta red fir, and lodgepole pine with a sparse understory of herbs and shrubs.
DISTRIBUTION AND EXTENT: The High Cascade Mountains in south central Oregon; MLRA 3. This series is of limited extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Crater Lake National Park, Oregon, 2001.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Andic soil properties - from 1 to 21 inches
Cambic horizon - from 5 to 21 inches (Bw1 horizon)
Ochric epipedon
Vitri (greatgroup) - the solum averages 60 to 90 percent glass and has an air-dry 15 bar moisture content of 3 to 12 percent
All depths to diagnostic horizons and features found in the range of characteristics are measured from the top of the first mineral horizon.
Runoff is moderate due to the hydrophobic nature of the surface horizon. If this property is not present, runoff will be low.
ADDITIONAL DATA: NSSL S00OR-035-001.