LOCATION HOLLOWTREE CA

Established Series
Rev. CAR/DJE/JWH/KP
10/2016

HOLLOWTREE SERIES

The Hollowtree series consists of moderately deep, well drained soils formed in residuum weathered from sandstone. Hollowtree soil are on hills and mountains and have slopes of 9 to 75 percent. The annual precipitation is about 1650 millimeters (65 inches) and the mean annual temperature is about 13 degrees C (55 degrees F).

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Ultic Haploxeralfs

TYPICAL PEDON: Hollowtree gravelly sandy loam - on an east facing convex slope under Douglas-fir, tanoak and madrone at 1097 meters (3,600 feet) elevation. (Colors are for dry soil unless otherwise stated. When described June 3, 1981, the soil was moist throughout.)

Oi--0 to 5 centimeters (0 to 2 inches); undecomposed and partially decomposed litter of tanoak and Douglas-fir within a mulch of hard subrounded sandstone gravel, 2-75 mm in diameter; About 60 percent of the surface covered with gravel.

A--5 to 20 centimeters (2 to 8 inches); light yellowish brown (10YR 6/4) gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and nonplastic; common very fine and fine and few medium roots; few very fine and fine tubular and interstitial pores; 20 percent hard subangular gravel (2 to 75 mm); moderately acid (pH 6.0); clear wavy boundary. (8 to 18 centimeters thick)

Bt1--20 to 48 centimeters (8 to 19 inches); very pale brown (10YR 7/4) very gravelly loam, yellowish brown (10YR 5/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and medium and few coarse roots; few very fine tubular and common very fine interstitial pores; common faint clay films on faces of peds and lining pores; 35 percent hard subrounded gravel (2 to 75 mm) and 5 percent hard subrounded cobbles (7.5 to 25cm) ; moderately acid (pH 6.0); clear wavy boundary. (15 to 35 centimeters thick)

Bt2--48 to 74 centimeters (19 to 29 inches); very pale brown (10YR 7/4) very gravelly sandy clay loam, yellowish brown (10YR 5/4) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common fine and medium and few coarse roots; few very fine tubular and many very fine interstitial pores; common faint and distinct clay films on faces of peds and lining pores; 30 percent hard subrounded gravel (2 to 75 mm) and 10 percent hard angular cobbles (7.5 to 25 cm); moderately acid (pH 6.0); clear wavy boundary. (15 to 35 centimeters thick)

Bt3--74 to 102 centimeters (29 to 40 inches); yellow (10YR 7/6) very gravelly sandy clay loam, yellowish brown (10YR 5/6) moist; moderate medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common medium and few coarse roots; few very fine tubular and many very fine interstitial pores; few faint clay films on faces of peds; 30 percent hard through soft subrounded gravel (2 to 75 mm) and 5 percent hard subangular cobbles (7.5 to 25 cm); moderately acid (pH 6.0); abrupt irregular boundary. (13 to 30 centimeters thick)

R--102 to 114 centimeters (40 to 45 inches); hard fractured sandstone; fractures are less than 1 mm wide and from 5 to 30 cm apart.

TYPE LOCATION: Mendocino County, California; from Branscomb road, take the Cahto Peak access road and turn onto the Stoten Opening road and head to within 100 yards south of the gate. Turn down slope and head 200 yards to the site; 1,400 feet south and 700 feet west of the northeast corner of sec. 7, T. 21 N., R. 15 W.; USGS Branscomb Quadrangle, Ca; WGS84 Decimal degrees 39.6923 latitude and -123.57111 longitude; UTM zone 10 450935.12938mE, and 4393749.43802mN; NAD 83. .

RANGE IN CHARACTERISTICS: Depth to a lithic contact ranges from 50 to 100 centimeters. The mean annual soil temperature ranges from 13 to 15 degrees C. The soil between the depths of 35 centimeters and the lithic contact is moist in all parts from November 1 through June 1 and is dry in all parts from July 15 through October 1 in most years. The particle-size control section averages from 18 to 27 percent clay.

The A horizon is 10YR 4/2, 5/2, 5/3, 5/4, 6/2, 6/3, 6/4, 7/2, 7/3 or 7/4. Moist color is 10YR 3/2, 3/3, 4/2, 4/3, 4/4, 5/4 or 7.5YR 3/2. Clay content ranges from 10 to 20 percent. Gravel content ranges from 15 to 35 percent, and cobble content ranges from 0 to 5 percent. The A horizon is less than 18 centimeters thick. Reaction is strongly through slightly acid. Base saturation (sum) ranges from 35 to 60 percent.

The Bt horizon is 10YR 5/4, 5/6, 6/4, 7/3, 7/4, 7/6 or 7.5YR 5/4. Moist color is 10YR 5/4, 5/6, 7.5YR 3/4, 4/4, 5/6 or 5YR 5/4. It is very gravelly sandy loam, very gravelly loam, very gravelly sandy clay loam, gravelly loam or gravelly sandy loam. Clay content ranges from 15 to 27 percent. Gravel content ranges from 25 to 60 percent and cobble content ranges from 0 to 35 percent. Total coarse fragment content ranges from 35 to 60 percent. Reaction is strongly or moderately acid. Base saturation (sum) ranges from 40 to 75 percent.

Some profiles contain a BC or C horizon. Colors are the same as the Bt horizon. It is extremely cobbly sandy loam or extremely gravelly sandy loam with 2 to 20 percent clay and 60 to 80 percent total coarse fragment content.

COMPETING SERIES: These are the Abegg, Brownscreek, Chimneyrock, Hambone, and Holohan series. The Abegg, Hambone, Holohan soils are greater than 100 centimeters deep. Brownscreek soils are formed in mica schist. Chimneyrock soils are deep to conglomerate bedrock.

GEOGRAPHIC SETTING: The Hollowtree soils are on hills and mountains. Slopes are 9 to 75 percent. Elevations are 152 to 1220 meters (500 to 4,000 feet). The soils formed in residuum weathered from sandstone. The climate is subhumid with warm dry summers and cool moist winters. Mean annual precipitation is 1140 to 3300 mm (45 to 130 inches) with occasional snowfall above 760 meters. Mean January temperature is about 6 degrees C and the mean July temperature is about 21 degrees C. The mean annual temperature is about 13 degrees C. The frost-free period is about 150 to 290 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Holohan soils and the Casabonne, Dann, Pardaloe, Witherell, Wohly, Woodin, and Yorkville soils. Casabonne, Dann, Pardaloe and Yorkville soils are deep or very deep. Casabonne, Witherell, Wohly and Yorkville soil have a nonskeletal control section. Witherell soils are shallow. Dann soils have a ferritic mineralogy. Yorkville soils have a fine textured control section and a thermic soil temperature regime. Yorkville and Witherell soils are under grassland.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained; surface runoff under bare soil conditions is medium to high; moderately high saturated hydraulic conductivity.

USE AND VEGETATION: This soil is used for timber and firewood production, wildlife habitat and watershed. Vegetation consists of tanoak, Pacific madrone, Douglas-fir, California huckleberry and interior live oak.

DISTRIBUTION AND EXTENT: Siskiyou-Trinity Area, MLRA 5. The series is moderately extensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Mendocino County, Eastern Part, California, 1985.

REMARKS: The activity class was added to the classification in February of 2003. - ET

Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the surface layer from 0 to 20 centimeters (O and A horizons)

Argillic horizon - the zone from 20 to 102 centimeters (Bt1, Bt2, Bt3
horizons)

Particle size control section - the zone between 20 and 70 centimeters (Bt1 and Bt2) averages 27 percent clay, by weight, 32 percent gravel and 7 percent cobble, by volume.

ADDITIONAL DATA: NASIS Pedon User Site ID: 1981CA045001

Soil classified using Keys to Soil Taxonomy, 12th edition

National Cooperative Soil Survey
U.S.A.