LOCATION AVIS CAEstablished Series
TAXONOMIC CLASS: Ashy-skeletal, amorphic, nonacid, frigid Vitrandic Xerorthents
TYPICAL PEDON: Avis very stony sandy loam - on a northeast facing convex slope of 15 percent under white fir at 5,840 feet elevation. (Colors are for dry soil unless otherwise stated. When described August 29, 1973, the soil was dry throughout).
O1 & O2--3 inches to 0; new and partially decomposed needles, twigs, bark, leaves and other organic debris. Cobbles and stones make up 15 to 50 percent of this horizon. (1/2 to 4 inches thick)
A1--0 to 6 inches; yellowish brown (10YR 5/4) very stony sandy loam, dark yellowish brown (10YR 3/4) moist; weak fine and very fine granular structure; soft, very fragile, nonsticky and nonplastic; many very fine, fine, medium and coarse roots; many fine and very fine interstitial pores; 5 percent pebbles, 10 percent cobbles and 15 percent stones; neutral (pH 7.0); abrupt smooth boundary. (3 to 6 inches thick)
A2--6 to 13 inches; yellowish brown (10YR 5/4) very stony sandy loam, dark yellowish brown (10YR 4/4) moist; weak very fine and fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium and coarse roots; many very fine and fine interstitial pores; 5 percent pebbles, 10 percent cobbles and 15 percent stones; slightly acid (pH 6.5); abrupt wavy boundary. (6 to 8 inches thick)
C--13 to 34 inches; light yellowish brown (10YR 6/4) very gravelly loamy sand, dark yellowish brown (10YR 4/4) moist; massive; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium and coarse roots; many fine interstitial pores; 30 percent pebbles, 10 percent cobbles and 2 percent stones; slightly acid (pH 6.5); abrupt wavy boundary. (11 to 26 inches thick)
2C1--34 to 47 inches; yellowish brown (10YR 5/4) very gravelly loamy sand, dark yellowish (10YR 3/4) moist massive; soft, very friable, nonsticky and nonplastic; many very fine, fine, medium and coarse roots; many fine and very fine interstitial pores; 30 percent pebbles, 10 percent cobbles and 5 percent stones; slightly acid (pH 6.50; abrupt wavy boundary. (10 to 15 inches thick)
2C2--47 to 60 inches; yellowish brown (10YR 5/4) very gravelly sand, dark yellowish brown (10YR 3/4) moist; single grained; loose; many very fine, fine, medium and coarse root; 30 percent pebbles, 10 percent cobbles and 5 percent tones; medium acid (pH 6.0); gradual wavy boundary. (10 to 15 inches thick)
2C3--60 to 72 inches; yellowish brown (10YR 5/4) very gravelly sand, dark yellowish brown (10YR 3/4) moist; single grained; loose; 30 percent pebbles, 15 percent cobbles and 5 percent stones; medium acid (pH 6.0).
TYPE LOCATION: Siskiyou County, California; on the northeast side of Goosenest Mountain, a volcanic peak about 15 miles east of Montague; about 2 miles southwest of Bull Meadows or 1.4 miles northwest of International Paper Road ID3; approximately 2,150 feet south and 300 feet west of the northeast corner section 21, T. 45 N., R. 3 W., on the west side of a dirt logging road.
RANGE IN CHARACTERISTICS: The thickness of the volcanic ash mantle over the pyroclastic sands is about 20 to 40 inches. Depth to fractured lava flow rock is 60 to 80 inches or more. The mean annual soil temperature is 42 to 46 degrees F. The soil temperature exceeds 41 degrees F from May 1 to November 10 and exceeds 47 degrees F from June 1 to October 20. The soil is dry in the 12 to 48 inches control section from mid-July to mid-October. It is moist in some or all parts the rest of the year. Base saturation ranges from 20 to 50 percent throughout the soil. The NaF pH ranges from 10.9 in the surface to 9.9 at depths of 40 to 72 inches. Lava flow rock fragments consisting of cobbles, gravel and stones occur throughout the soil. They make up 35 to 70 percent of the 10 to 40 inch control section. Stones and cobbles cover 5 to 50 percent of the soil surface. In some pedons there is very weak silica cementation of the upper few inches of the 2C horizon and strata of 1/4 to 2 inches thick deposit of finer volcanic ash between pyroclastic sand strata.
The A horizon is 10YR 5/2, 5/3, 6/2, 6/3. Moist colors are 10YR 3/3, 3/4, 5/2, 4/3, 4/4. Reaction is neutral to medium acid. Texture is stony sandy loam or very stony sandy loam.
The C horizon is 10YR 5/3, 5/4, 6/3, 6/4 or 7.5YR 5/2, 6/2. Moist colors are 10YR 4/2, 4/3, 4/4. It is very gravelly loamy fine sand, very gravelly loamy sand or very gravelly sand. Reaction is slightly acid or medium acid.
The 2C horizon is 10YR 5/4, 6/3, 6/4 and moist color of 10YR 3/4, 4/3, or 4/4. Texture is very gravelly loamy fine sand, very gravelly loamy sand or very gravelly sand. Reaction is slightly acid or medium acid.
COMPETING SERIES: These are the Deetz, Delaney, Oosen, Plutos and Shasta series in other families. All these soils have less than 35 percent rock fragments in the control section. In addition, Deetz and Delaney soils have a mesic soil temperature regime. Plutos soils have a mesic soil temperature regime and are 20 to 40 inches deep to hard basalt. Shasta soils have an umbric epipedon ashy control section and a mesic soil temperature regime.
GEOGRAPHIC SETTING: Avis soils are on slopes of volcanic mountainous peaks at elevations of 5,000 to 7,000 feet. Slopes are 5 to 50 percent. The soils formed in pyroclastic ashy materials deposited over and in highly fractured and broken lava flow rock. Barren lava flows are common and large boulders are throughout the geographic area and are in the soil and are partially exposed at the surface. The climate is continental and subhumid with warm nearly dry summers and cold moist winters. Mean annual precipitation is 30 to 50 inches. Snowfall is 24 to 48 inches and covers the high elevation lands from early December until early April in most years. Mean January temperature is 23 to 28 degrees F; mean July temperature is 60 to 64 degrees F; mean annual temperature is 38 to 45 degrees F. Frost-free season is 35 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Esro, Iller, Orset, Sheld and the competing Oosen soils. Esro soils have an aquic moisture regime and a fine-silty control section. Iller and Sheld soils have umbric epipedons and medial over loamy-skeletal and medial-skeletal control sections respectively. Orset soils have base saturation of greater than 60 percent and a coarse-loamy control section.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; medium to rapid runoff; rapid permeability. The A1 horizon is hydrophobic when dry.
USE AND VEGETATION: Used mainly for woodland. Native vegetation is mainly Douglas-fir, white fir, California red fir, incense cedar and ponderosa pine. Shrubs are snowbrush ceanothus, Sierra chinkapin, bearberry manzanita and snowberry.
DISTRIBUTION AND EXTENT: Volcanic peaks in the northern California portion of the Cascade range. The soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Siskiyou County, California 1978.
REMARKS:
Additional Data: Soil was sampled in June 1974 by the Riverside Laboratory, Pedon No. -S74CA-093-9.
Last revised by the state on 4/86.