LOCATION TRAMWAY CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, active, isomesic Ultic Hapludalfs
TYPICAL PEDON: Tramway loam - on an east facing convex slope of 40 percent under redwood, Douglas-fir, tanoak, swordfern and oxalis at 240 feet elevation. (Colors are for dry soil unless otherwise stated. When described on March 26, 1979 the soil was moist throughout).
Oi--2 inches to 0; litter of redwood, Douglas-fir and tanoak.
A--0 to 7 inches; light brownish gray (10YR 6/2) loam, very dark grayish brown (10YR 3/2) moist; strong medium subangular blocky and moderate fine granular structure; hard, very friable, slightly sticky and slightly plastic; common fine, medium and coarse and few very fine roots; few very fine tubular and common fine interstitial pores; 10 percent concretions; moderately acid (pH 6.0); clear wavy boundary. (5 to 8 inches thick)
BAt--7 to 12 inches; pale brown (10YR 6/3) loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few fine and common coarse and medium roots; few fine interstitial and very fine tubular pores; common thin clay films on faces of peds and lining pores; 5 percent concretions; moderately acid (pH 5.8); clear wavy boundary. (3 to 7 inches thick)
Bt1--12 to 18 inches; light yellowish brown (10YR 6/4) clay loam, dark yellowish brown (10YR 4/4) moist; weak medium and coarse subangular blocky structure; hard, friable, slightly sticky and slightly plastic, few fine and common medium and coarse roots; few fine interstitial and few very fine tubular pores; many thin clay films on faces of peds and lining pores; 5 percent concretions; strongly acid (pH 5.5); gradual wavy boundary. (4 to 10 inches thick)
Bt2--18 to 28 inches; light yellowish brown (10YR 6/4) clay loam, dark yellowish brown (10YR 4/4) moist; weak medium and coarse subangular blocky structure; hard, firm, slightly sticky and plastic; few fine and common coarse and medium roots; few fine interstitial pores; many moderately thick clay films on faces of peds and lining pores; 5 percent concretions; strongly acid (pH 5.2); gradual irregular boundary. (7 to 15 inches thick)
Crt--28 to 41 inches; light yellowish brown (10YR 6/4) highly weathered fractured sandstone; few medium and coarse roots following fracture faces; continuous moderately thick clay films on fracture faces.
TYPE LOCATION: Mendocino County, California; about 1 mile from Hwy. 20 on Twolog Creek logging road, up west slope 100 feet; 500 feet south and 2600 feet east of the northwest corner of sec. 13, T.17N., R.16W.; Comptche quadrangle.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact and thickness of the solum is 20 to 40 inches. The mean annual soil temperature ranges from 50 to 56 degrees F. The difference between mean summer and mean winter soil temperature ranges from 3 to 6 degrees F. The soil between depths of 7 and 19 inches is moist in all parts from November 1 to August 15 and is dry in some part from September 1 to October 1 in most years. The particle-size control section averages from 20 to 35 percent clay. Reaction is strongly acid through slightly acid.
The A horizon is 10YR 5/2, 5/3, 6/2, 6/3 or 7/3. Moist color is 10YR 3/2, 3/3, 4/2, 4/3 or 4/4. Clay content ranges from 15 to 20 percent. Gravel content is 0 to 15 percent. Where mollic colors occur, the horizon is not thick enough to meet the requirements of a mollic epipedon.
The Bt horizon is 10YR 5/3, 6/3, 6/4, 7/4, 7/6; 7.5YR 6/4 or 6/6. Moist color is 10YR 4/3, 4/4, 5/3, 5/4; 7.5YR 4/2 or 4/4. It is loam, clay loam or gravelly clay loam. Clay content ranges from 20 to 35 percent. Gravel content is 0 to 25 percent. Base saturation (sum) is 40 to 75 percent and is less than 60 percent in the lower part of the Bt. Gravel content is 0 to 25 percent.
COMPETING SERIES: These are the Carlain (CA) and Irmulco (CA) soils. Carlain soils are very deep have a very gravelly lithological discontinuity in the lower Bt horizon. Irmulco soils are 60 to 80 inches deep to a paralithic contact.
GEOGRAPHIC SETTING: The Tramway soils occur on mountains. Slopes are 9 to 75 percent. Elevation is 10 to 800 feet. The soils formed in material weathered from sandstone. The climate is humid with cool foggy summers and cool moist winters. A strong coastal fog influence limits the diurnal and annual range of temperature. Mean annual precipitation varies from 40 to 70 inches. Mean January temperature is 50 degrees F.; mean July temperature is 55 degrees F.; and mean annual temperature is 53 degrees F. The frost-free season is 290 to 365 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Carlain and Irmulco soils and the Dehaven, Hotel, and Vandamme soils. Dehaven and Hotel soils are on mountain sideslopes and formed from hard sandstone. Dehaven and Hotel soils are loamy-skeletal. Vandamme soils are on ridgetops and upper sideslopes slopes of mountains. Vandamme soils are clayey, have a base saturation of 5 to 35 percent above the paralithic contact and are 40 to 60 inches deep to a paralithic contact.
DRAINAGE AND PERMEABILITY: Well drained; surface runoff under bare soil conditions is medium through very rapid; moderate permeability.
USE AND VEGETATION: This soil is used for commercial timber production, wildlife and watershed. Natural vegetation consists of redwood, Douglas-fir, grand fir, tanoak, huckleberry, swordfern, oxalis, and rhododendron.
DISTRIBUTION AND EXTENT: Northern coastal California. Soil only occurs in zone of marine influence. The series is moderately extensive. MLRA 4.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Mendocino County, California, Western Part, 1993.
REMARKS: The activity class was added to the classification in March of 2003. Competing series were not checked at that time. - ET
Diagnostic horizons and features recognized in this pedon:
Ochric epipedon -- 0 to 7 inches (A).
Argillic horizon -- 7 to 28 inches (BAt, Bt1, Bt2).
Mineralogy -- mixed. Mineralogy determined to be mixed by Lincoln Lab.
Many areas mapped as Tramway soils were mapped as Josephine soils by the California Soil-Vegetation survey 1947-1950.