LOCATION ST. NICHOLAS            AK

Established Series
Rev. RWG/WDL/JPM
02/2022

ST. NICHOLAS SERIES

The St. Nicholas series consists of shallow to schist, poorly drained soils formed in colluvium and residuum. These soils occur on gently sloping to very steep backslopes of hills, mountains, and valleysides. Slopes range from 5 to 100 percent. The mean annual precipitation is in excess of 120 inches and the mean annual temperature is 40 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Lithic Cryaquods

TYPICAL PEDON: St. Nicholas very fine sandy loam -- on a west facing slope of 60 percent at 1600 feet elevation under forest vegetation. (All colors are for moist soil)

Oi--7 to 4 inches; undecomposed forest litter.

Oa--4 to 0 inches; reddish black (5R 2/1) decomposed forest litter; many very fine, few fine, medium, and coarse roots; extremely acid (pH 4.0); abrupt smooth boundary. (1 to 6 inches thick).

E--0 to 2 inches; dark brown (7.5YR 3/1) very fine sandy loam; weak fine subangular blocky structure; very friable; 10 percent gravel; common very fine and fine roots; extremely acid (pH 4.0); abrupt smooth boundary. (0 to 3 inches thick)

Bhs1--2 to 5 inches; very dark brown (10YR 2/2) very gravelly sandy loam; common yellow (10YR 7/8) mottles; weak fine subangular blocky structure very friable; 30 percent gravel; few fine, common very fine roots; extremely acid (pH 4.0); clear wavy boundary.

Bhs2--5 to 14 inches; very dark brown (10YR 2/2) very gravelly silt loam; common yellowish brown (10YR 5/6) mottles; weak fine subangular blocky structure; nonsticky, nonplastic; 60 percent gravel; few fine roots; very strongly acid (pH 4.5); abrupt smooth boundary. (Combined B horizons: 6 to 12 inches thick)

R--14 inches; schist bedrock.

TYPE LOCATION: Ketchikan Area, Alaska. In the Carroll Inlet watershed; in the NW1/4, NW1/4, S35, T70S, R92E, Copper River Meridian.

RANGE IN CHARACTERISTICS: Depth to bedrock ranges from 4 to 16 inches. Weighted average of coarse fragments in the particle size control section ranges from 45 to 80 percent. The mean annual soil temperature ranges from 38 to 42 degrees F. and the mean summer soil temperature is 44 degrees F. Reaction throughout the profile ranges from extremely to very strongly acid.

The hue of the E horizon ranges from 5YR to 10YR, the value ranges from 3 to 7, and the chroma from 1 to 3. Texture is very fine sandy loam or loam.

The hue of the B horizon ranges from 2.5YR to 10YR, the value ranges from 2 to 7, and the chroma ranges from 1 to 8. The texture is silt loam, sandy loam, or loam with 45 to 80 percent coarse fragments.

COMPETING SERIES: This is the Purches (AK) series in the same subgroup. Purches soils do not have bedrock within 20 inches of the surface.

GEOGRAPHIC SETTING: St. Nicholas soils occur on gently sloping to very steep hillslopes and valleysides, and are underlain by noncalcareous bedrock. The climate is humid maritime with mean annual precipitation in excess of 120 inches. The mean annual air temperature is about 40 degrees F and the mean summer air temperature is about 50 degrees F. The slope gradient ranges from 5 to 100 percent. Elevations range from sea level to 2400 feet.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hydaburg, Sunnyhay, and Tolstoi series. Hydaburg and Sunnyhay soils are poorly drained organic soils in alpine areas. Tolstoi soils are well drained soils on hillslopes and mountainslopes.

DRAINAGE AND PERMEABILITY: Poorly drained. Moderately rapid permeability. Slow runoff. These soils receive such a large amount of rain and seep water that they are wet most of the time even though they are on very steep slopes.

USE AND VEGETATION: St. Nicholas soils are used for watershed protection, wildlife habitat, and recreation. The overstory vegetation consists of Alaska yellow-cedar, western hemlock, mountain hemlock, and Sitka spruce. The understory vegetation is mainly blueberry species, deer cabbage, and false hellebore.

DISTRIBUTION AND EXTENT: Southeast Alaska. The series is extensive.

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

SERIES ESTABLISHED: Hollis Area, Alaska, 1969.

REMARKS: Diagnostic horizons and features recognized in this soil are: a spodic horizon from 2 to 14 inches; weighted average of more than 35 percent coarse fragments from 0 to 14 inches; histic epipedon from 7 inches to 0, mottling throughout the spodic horizon; a cryic temperature regime is assumed; assumed less than 6 percent organic carbon in the upper 4 inches of the spodic horizon. The spodic horizon is identified based on field morphology alone. The St. Nicholas series is proposed as a benchmark soil series. The St. Nicholas series formerly classified as thixotropic-skeletal.

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National Cooperative Soil Survey
U.S.A.