LOCATION FORWARD CA
Established Series
Rev. SBJ/GMK/DJE/AEC
01/2023
FORWARD SERIES
The Forward series consists of moderately deep, well drained soils formed in material weathered from rhyolithic tuff. Forward soils are on hills and mountains and have slopes of 2 to 75 percent slopes. The mean annual precipitation is 45 inches and the mean annual temperature is 42 degrees F.
TAXONOMIC CLASS: Ashy, mixed, mesic Typic Vitrixerands
TYPICAL PEDON: Forward sandy loam--on an east facing slope of 24 percent in an area logged but under a dense stand of conifers and shrubs at an elevation of 3,800 feet. (Colors are for dry soil unless otherwise stated.)
Oi--0 to 2 inches (0 to 5 cm); fresh pine and oak litter, partially decomposed in lower portion.
A1--2 to 3 inches (5 to 8 cm); grayish brown (10YR 5/2) sandy loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; soft, very friable; few very fine roots; many very fine pores; slightly acid; abrupt wavy boundary.
A2--3 to 9 inches (8 to 23 cm); light brownish gray (10YR 6/2) sandy loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; soft, very friable; common very fine, fine and medium roots; many very fine pores; moderately acid; abrupt wavy boundary. (Combined thickness of the A horizon is 3 to 15 inches.)
Bw1--9 to 17 inches (23 to 43 cm); very pale brown (10YR 7/3) coarse sandy loam, pale brown (10YR 6/3) moist; weak medium subangular blocky structure; slightly hard, very friable; common very fine and fine roots; many very fine pores; moderately acid; clear irregular boundary. (6 to 14 inches thick)
Bw2--17 to 26 inches (43 to 66 cm); pale yellow (2.5Y 8/4) coarse sandy loam, light yellowish brown (2.5Y 6/4) moist; weak medium subangular blocky structure; slightly hard, very friable; few medium and large roots throughout with a dense layer of very fine, fine, medium and coarse roots resting abruptly on tuff below; strongly acid; abrupt wavy boundary. (6 to 24 inches thick)
Cr--26 to 32 inches (66 to 81 cm); pale yellow (2.5Y 8/4) massive rhyolitic tuff, ranging in color from nearly white to pale yellow. The tuff contains fine angular particles of volcanic ash and angular fragments of pumice. Roots penetrate the tuff only along fracture planes.
TYPE LOCATION: Tehama County, California; about 1-1/2 miles southwest of Forward Mill near the center of the SW1/4 of SW1/4 of sec. 27, T. 30 N., R. 2 E. 40 degrees 25 minutes 29 seconds N 121 degrees 45 minutes 39.9 seconds W, NAD83
RANGE IN CHARACTERISTICS: Rhyolitic tuff occurs at depths of 20 to 40 inches. The solum contains 60 to 80 percent vitric material in the silt, sand and gravel fractions. Gravel fraction of the whole soil ranges from 5 to 35 percent. The mean annual soil temperature is about 52 degrees to 57 degrees F. The soils are usually moist but are dry in late May or June and remain dry until October.
The A horizon is 10YR 4/2, 5/2, 6/1, 6/2, or 6/3, 7/1 or 7/2. Moist color is 10YR 2/2, 3/2, 3/3, 4/2, 4/4, 5/2, 5/3 or 5/4. Dry colors of 4/2 or 5/2 and moist colors of 2/2 or 3/2 only occur in the upper 1 to 3 inches. It is loamy sand, sandy loam or light loam and may be gravelly. It is slightly to strongly acid.
The Bw horizon is 10YR 5/3, 6/2, 6/3, 7/1, 7/2, 7/3, 7/4; 2.5Y 7/4, 8/2, or 8/4. Moist color is 10YR 4/3, 4/4, 5/2, 5/3, 5/4, 6/3; 2.5Y 5/2, 6/2, 6/4, 7/4, or 8/4. It is coarse sandy loam, sandy loam or loam and may be gravelly. It is slightly to very strongly acid. Some pedons have an A or BA horizon transitional to the Bw horizon, or the BC horizon may be absent.
The C horizon, where present, is 10YR 7/1, 7/2, 7/3, 8/3; 2.5Y 6/2, 7/2, 8/3, or 8/4. Moist color is 10YR 5/3, 6/2, or 6/3 and has a lower chroma or yellower hue than the overlying Bw horizon. It is slightly acid to very strongly acid.
COMPETING SERIES: These are the
Crater Lake,
Synarep, and
Toutle series. Crater Lake soils lack a paralithic contact at depths of 20 to 40 inches. Synarep and Toutle soils are over 60 inches deep.
GEOGRAPHIC SETTING: Forward soils are on hills and mountains. Slopes are 2 to 75 percent. The soils formed in material overlying rhyolitic tuff. Elevations are 400 to 4,500 feet. The climate is subhumid with warm to hot dry summers and cool moist winters. Mean annual precipitation is 30 to 60 inches. Some areas may have up to 25 inches of annual snowfall. Mean January temperature is 34 degrees F, mean July temperature is 67 degrees F, and mean annual temperature varies from 48 degrees to 55 degrees F. Frost-free season is 150 to 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Aiken,
Cohasset, and
Nanny soils. Aiken and Cohasset soils have argillic horizons. Nanny soils have more than 35 percent coarse fragments.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately rapid permeability above the tuff.
USE AND VEGETATION: Used mainly for timber production. Natural vegetation is ponderosa pine, Douglas-fir, incense cedar, black oak, prostrate ceanothus, manzanita and a few herbaceous plants.
DISTRIBUTION AND EXTENT: Occurs at moderate elevations in the Cascade and Coast Ranges of northern California. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Tehama County, California, 1962.
REMARKS: The soils mapped as Forward in Napa County were formerly named the Butte series.
Edits made after sdjr projects. Substitute particle-size class changed to ashy based on air-dry 15 bar water data from lab data for OSD profile (S1954-CA-52-011) of less than 12 percent. There is insufficient lab data to determine Andic soil properties. - AEC
National Cooperative Soil Survey
U.S.A.