LOCATION MOSMAN AK
Established Series
Rev. EJK/JPM
05/2022
MOSMAN SERIES
The Mosman series consist of very shallow, well drained soils formed in residuum or colluvium. Mosman soils are on mountain sideslopes and hillslopes. Slope ranges from 5 to 120 percent. Mean annual temperature is about 42 degrees F. and the average annual precipitation is about 110 inches.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Lithic Humicryods
TYPICAL PEDON: Mosman very gravelly loam -- on a west facing slope of 85 percent under a canopy of mixed western hemlock, Sitka spruce, and Alaska yellow cedar at 1680 feet. (All colors are for moist soil)
Oi--7 to 5 inches; dark reddish brown (5YR 2.5/2) peat; weak medium granular structure; friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; very strongly acid (pH 4.5 Truog); clear wavy boundary. (1 to 4 inches thick)
Oa--5 to 0 inches; black (10YR 2/1) muck; moderate fine granular structure; friable, nonsticky and nonplastic; many very fine, fine, medium, and coarse roots; strongly acid (pH 5.0 Truog); clear wavy boundary. (2 to 6 inches thick)
E--0 to 1 inch; dark brown (10YR 4/3) very gravelly loam; moderate fine subangular blocky structure; friable, slightly sticky and slightly plastic; 40 percent gravel; common very fine, fine, medium, and coarse roots; strongly acid (pH 5.0 Truog); gradual diffuse boundary. (0 to 2 inches thick)
Bhs--1 to 11 inches thick; dark brown (10YR 3/3) very gravelly loam; moderate fine subangular blocky structure; friable, slightly sticky and slightly plastic; 60 percent gravel; common very fine, fine, medium and coarse roots; moderately acid (pH 5.5 Truog); gradual diffuse boundary. (2 to 12 inches thick).
R--11 inches; granodiorite bedrock.
TYPE LOCATION: Dahlgren Peak area, Farragut Bay, Alaska, section 33, T.53S., R.76E., Copper River meridian.
RANGE IN CHARACTERISTICS: MAST ranges from 38 to 42 degrees F. Thickness of the solum and depth to bedrock ranges from 3 to 14 inches. Coarse fragment content in the particle size control section ranges from 35 to 65 percent with 35 to 50 percent gravel and 0 to 15 percent cobble and stones. Reaction is very strongly acid to moderately acid. Organic carbon content of the upper 4 inches of the spodic horizon exceeds 6 percent.
The O horizon has hue ranging from 10R to 10YR; value moist of 2 or 2.5; and chroma moist of 1 or 2.
The E horizon has hue from 10YR to 5YR; value moist from 4 to 6; and chroma moist from 1 to 3. Texture is loam or silt loam with 20 to 50 percent coarse fragments. The E horizon is absent in some pedons.
The Bhs horizon has hue ranging from 2.5YR to 10YR; value and chroma moist from 2 to 4. Texture is loam or silt loam with 35 to 70 percent coarse fragments.
A Bs horizon is present in some pedons.
COMPETING SERIES: These are the
Hannegan(WA),
Naukati (AK),
Peril (AK) and
Tolstoi (AK) series. Hannegan soils have volcanic ash throughout the profile. Naukati, Peril and Tolstoi soils are all deeper than 14 inches to bedrock.
GEOGRAPHIC SETTING: Mosman soils are on hillslopes and mountainsides. These soils are formed in colluvium and residuum and are underlain by bedrock. The climate is humid maritime with mean annual precipitation ranging from 60 to 150 inches. Mean annual temperature ranges from 40 to 45 degrees F. Slope gradient ranges from 5 to 120 percent. Elevationrange from sea level to 2000 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These include the
Kupreanof, McGilvery,
St. Nicholas,
Tonowek, and
Tuxekan soils. Kupreanof soils lack a histic epipedon and are developed in deep till and colluvium on concave slopes. McGilvery soils are on similar positions and consist of forest litter over bedrock. St. Nicholas soils are at higher elevations and are poorly drained. Tonowek and Tuxekan soils developed in alluvium on floodplains and stream terraces.
DRAINAGE AND PERMEABILITY: Well drained. Moderate permeability. Slow runoff.
USE AND VEGETATION: The Mosman soils are used for timber production, watershed protection, wildlife habitat, and recreation. The overstory vegetation is dominantly western hemlock and Sitka spruce with lesser amounts of Alaska yellow cedar and western red cedar. The understory vegetation is vaccinium, rusty menziesia, ferns, and mosses.
DISTRIBUTION AND EXTENT: Southeast Alaska. The series is extensive.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: WASILLA, ALASKA
SERIES ESTABLISHED: Chatham Survey Area, Tongass National Forest, Alaska, 1992.
REMARKS: Diagnostic features and horizons recognized in this profile include: an albic horizon from 0 to 1 inch; a spodic horizon from 1 to 11 inches; assumed organic carbon content greater than 6 percent in the upper 4 inches of the spodic horizon; a lithic contact at 11 inches; loamy-skeletal particle size from 0 to 11 inches; a cryic temperature regime.
National Cooperative Soil Survey
U.S.A.