LOCATION TIMBERCRATER            OR

Established Series
Rev. ACM/TDT
01/2011

TIMBERCRATER SERIES

The Timbercrater series consists of very deep, excessively drained soils that formed in ash fall deposits of pumice and ash. Timbercrater soils are on ridges, mountain flanks and mountain tops and have slopes of 0 to 80 percent. The mean annual precipitation is about 60 inches and the mean annual temperature is about 41 degrees F.

TAXONOMIC CLASS: Ashy-pumiceous, amorphic Typic Vitricryands

TYPICAL PEDON: Timbercrater ashy paragravelly loamy sand, on a 12 percent slope, forest. (Colors are for moist soils unless otherwise noted. Described by C. Ducey, A. Moore, and G. Weinheimer, 7/27/99.)

Oi--0 to 2 inch; slightly decomposed needle litter; abrupt smooth boundary. (1 to 3 inches thick)

A--2 to 5 inches; dark brown (10YR 3/3) paragravelly ashy loamy sand, brown (10YR 4/3) dry; weak fine granular structure; loose, nonsticky and nonplastic; many very fine, fine, and medium roots; many fine interstitial pores; 25 percent pumice gravel and 5 percent andesite gravel; moderately acid (pH 5.9); clear smooth boundary. (2 to 9 inches thick)

Bw--5 to 16 inches; brown (10YR 4/3) very paragravelly ashy loamy sand, yellowish brown (10YR 5/4) dry; weak fine subangular blocky structure parting to single grain; loose, nonsticky and nonplastic; common very fine, fine, and medium roots; many fine interstitial pores; 50 percent pumice gravel; slightly acid (pH 6.3); clear wavy boundary. (5 to 16 inches thick)

C1--16 to 20 inches; yellowish brown (10YR 5/6) extremely paragravelly ashy sand, brownish yellow (10YR 6/6) dry; single grain; loose, nonsticky and nonplastic; many very fine and fine and common medium roots; many fine and medium interstitial pores; 90 percent pumice gravel with yellow (10YR 7/6) interior; moderately acid (pH 6.0); clear wavy boundary. (0 to 35 inches thick)

C2--20 to 62 inches deep; brownish yellow (10YR 6/6) extremely paragravelly ashy sand, yellow (10YR 7/8) dry; few medium roots; 85 percent pumice gravel with very pale brown (10YR 8/4) interior; moderately acid (pH 6.0).

TYPE LOCATION: Klamath County, Oregon, Crater Lake National Park; about 3.1 miles south and 3.7 miles west of the northeast corner of the park; UTM Zone 10, 575491 easting, 4766072 northing, NAD 83 (GPS). Latitude - 43 degrees, 02 minutes, 37 seconds North, Longitude - 122 degrees, 04 minutes, 23.5 seconds West.

RANGE IN CHARACTERISTICS: The solum is 14 to 25 inches thick. Depth to bedrock is greater than 60 inches. 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. The solum has andic soil properties throughout 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+Fe is 5 to 8. The particle-size control section averages 35 to 80 percent pumice fragments.

Some pedons lack an A horizon and have an albic horizon (E) up to 3 inches thick; when this occurs slopes are typically less than 15 percent.

The A horizon has value of 2 or 3 moist, 3 through 5 dry, and chroma of 2 or 3 moist and dry. It is ashy loamy sand or ashy sandy loam and it contains 15 to 35 percent pumice paragravel and 0 to 10 percent andesite gravel.

The Bw horizon has value of 3 or 4 moist, 4 or 5 dry, and chroma of 3 or 4 moist and dry. It contains 20 to 60 percent pumice paragravel.

The C horizon has value of 3 through 6 moist, 4 through 8 dry, and chroma of 4 through 8 moist and dry. It is ashy sand, ashy loamy sand, or pumice and contains 70 to 95 percent pumice paragravel.

COMPETING SERIES: This is the Umak series. Umak soils are dominated by paracobbles throughout the profile and are on ash flows.

GEOGRAPHIC SETTING: Timbercrater soils are on ridges, mountain flanks and mountain tops at elevations of 5,000 to 8,900 feet. Slopes range from 0 to 80 percent. The soils formed in ash fall deposits of pumice and ash 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 Umak series. Castlecrest and Unionpeak are ashy. Llaorock is medial-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, watershed, 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 2 to 16 inches

Ochric epipedon

Ashy-pumiceous - the profile contains greater than 65 percent pumice fragments

Vitri (greatgroup) - the solum averages 60 to 90 percent volcanic 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, depending on slope, may be low.

ADDITIONAL DATA: NSSL S00OR-035-002.

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National Cooperative Soil Survey
U.S.A.