LOCATION FORDSTERROR AK

Established Series
Rev. CSC/JMD/JPM
12/2022

FORDSTERROR SERIES

The Fordsterror series consists of moderately deep, somewhat poorly drained soils formed in colluvium and residuum from phyllite and schist on hillslopes and mountainslopes. Slopes range from 35 to 75 percent. Mean annual precipitation is in excess of 60 inches and the mean annual temperature is about 46 degrees F.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive Typic Humicryods

TYPICAL PEDON: Fordsterror silt loam - on a north facing slope of 35 percent at 60 feet elevation under conifer forest vegetation. (All colors are for moist soil)

Oi -- 4 to 3 inches; forest litter and living mosses; many fine, medium and coarse roots; extremely acid (pH 4.0); clear smooth boundary.

Oa -- 3 to 0 inches; dark reddish brown (5YR 2.5/2) muck; many fine, medium and coarse roots; extremely acid (pH 4.0); abrupt smooth boundary.

E -- 0 to 1 inch; brown (7.5YR 4/2) silt loam; weak fine subangular blocky structure; slightly sticky and slightly plastic; many fine and medium, few coarse roots; extremely acid (pH 4.0); abrupt smooth boundary. (1 to 4 inches thick)

Bhs -- 1 to 14 inches; dark reddish brown (5YR 2.5/2) gravelly silt loam; weak fine subangular blocky structure; slightly sticky and slightly plastic; many fine and medium, few coarse roots; many medium distinct dark yellowish brown (10YR 4/4) mottles near base of horizon; 20 percent gravel, 10 percent cobbles; very strongly acid (pH 4.5); gradual smooth boundary. (1 to 13 inches thick)

C -- 14 to 26 inches; very dark grayish brown (10YR 3/2) cobbly silt loam; massive; 10 percent gravel, 20 percent cobbles; common medium faint dark brown (10YR 3/3) mottles; strongly acid (pH 5.5); gradual irregular boundary. (0 to 27 inches thick)

R -- 26 inches; consolidated schist bedrock

TYPE LOCATION: Admiralty Cove, Chatham Area, Southeast, Alaska. NW1/4, SE1/4, Sec. 2, T.43S., R.66E., Copper River Meridian.

RANGE IN CHARACTERISTICS: MAST ranges from 38 to 42 degrees F. The thickness of the solum ranges from 2 to 17 inches. Depth to bedrock ranges from 20 to 40 inches. The particle size of the control section has less than 18 percent clay and more than 15 percent fine sand or coarser. Coarse fragment content in the control section ranges from 5 to 30 percent with 0 to 20 percent gravel and 0 to 20 percent cobbles. Reaction increases with depth, ranging from extremely acid to slightly acid. Buried horizons are present in many profiles.

Combined thickness of the O horizons ranges from 2 to 8 inches.

The E horizon has hue of 7.5YR or 10YR, and value from 4 to 8. Texture is commonly silt loam or sandy loam.

The Bhs horizon has hue of 5YR or 7.5YR, value of 2 or 3 and chroma from 1 to 3. Texture is commonly silt loam or sandy loam. Coarse fragment content ranges from 0 to 30 percent. Prominent or distinct mottles are present in the lower part of the horizon.

A mottled Bs horizon is present in some pedons. Value moist ranges from 3 to 5 and chroma moist from 4 to 6.

The C horizon has hue from 7.5YR to 2.5Y, value moist from 3 to 6 and chroma moist of 1 or 2. Texture is commonly silt loam or sandy loam. Coarse fragment content ranges from 15 to 30 percent. Prominent or distinct mottles are common.

COMPETING SERIES: These are the Diobsud (WA), Gallup (WA), Kulshan (WA), Potchub (WA), Tokeen (AK), Ulloa (AK), and Vixen (AK) series. Diobsud and Potchub soils have dense compact till within 40 inches of the surface. Gallup soils are deeper than 40 inches and contain volcanic ash. Kulshan soils contain volcanic ash and are not mottled. Tokeen soils have a solum thicker than 20 inches and are not mottled. Ulloa and Vixen soils have bedrock deeper than 40 inches.

GEOGRAPHIC SETTING: The Fordsterror soils are on hill and mountain sideslopes. The parent material is colluvium and residuum from phyllite and schist underlain by phyllite and schist bedrock. The climate is humid maritime with a mean annual precipitation range of 60 to 220 inches. The mean annual temperature is about 46 degrees F. and the mean summer temperature is about 57 degrees F. Elevation ranges from 0 to 2000 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These include the Passage, Kaikli, Snettisham, and Traitors soils on similar landforms. Passage and Traitors soils are well drained. Kaikli soils are very poorly drained organic soils. Snettisham soils are less than 20 inches deep to bedrock.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Moderate permeability. Runoff is very slow.

USE AND VEGETATION: The Fordsterror soils are used for timber production, watershed protection, wildlife habitat and recreation. The overstory is dominantly western hemlock. The understory is dominantly blueberry with some skunk cabbage.

DISTRIBUTION AND EXTENT: Southeast Alaska. The series is of moderate extent.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA

SERIES ESTABLISHED: Chatham Area, Tongass National Forest, Alaska, 1992.

REMARKS: Diagnostic horizons and features recognized in this pedon include: an albic horizon from 0 to 1 inch; a spodic horizon from 1 to 14 inches; cryic temperature regime; assumed organic carbon content of greater than 6 percent in the upper 4 inches of the spodic horizon; coarse-loamy particle size from 10 to 26 inches.

This series could classify as a Typic Cryaquod under the 1991 revised Spodosol criteria. This soil, however, does not exhibit the saturated conditions typical of an Aquod which is reflected in terms of forest productivity. Redoximorphic features are present lower in the spodic horizon and the soil exhibits characteristics of somewhat poor drainage. It is assumed the soil is not saturated to the surface nor does the capillary fringe extend to the surface during the year.

National Cooperative Soil Survey
U.S.A.