LOCATION LOGCABIN AK
Established Series
SDB
08/2025
LOGCABIN SERIES
Depth class: moderately deep to permafrost
Drainage class: poorly drained
Parent material: organic material over silty loess over sandy and gravelly alluvium and/or sandy and gravelly colluvium
Landscape: mountains
Landform: stream terraces
Slope: 0 to 20 percent
Mean annual precipitation: about 600 mm (24 in)
Mean annual air temperature: about -3 degrees C (27 degrees F)
Frost-free period: 89 to 103 days
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, nonacid, subgelic Fluvaquentic Aquorthels
TYPICAL PEDON: Logcabin silt loam in a sedge and moss community on a linear, convex stream terrace on a 9 percent slope at an elevation of 1216m (3990 ft).
Oi1--0 to 7 cm (0.0 to 3 in); peat, black (10YR 2/1) moist; very few very fine roots throughout; noneffervescent; very strongly acid (pH 4.9); clear smooth boundary (4 to 9 cm, 2 to 4 in)
Oi2--7 to 16 cm (3 to 6 in); peat, dark reddish brown (5YR 3/2) moist; very strongly acid (pH 4.9); clear smooth boundary (6 to 10 cm, 2 to 4 in)
A--16 to 22 cm (6 to 9 in); silt loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; hard, firm, nonsticky, nonplastic; nonsmeary; many very fine, common fine, and medium tubular pores; 3 percent subangular gravel by volume; strongly acid (pH 5.2); clear wavy boundary (4 to 7 cm, 2 to 3 in)
2Bg--22 to 53 cm (9 to 21 in); very stony sandy clay loam, dark gray (5Y 4/1) reduced and very dark grayish brown (10YR 3/2) oxidized moist; weak medium subangular blocky structure; very hard, very firm, moderately sticky, moderately plastic; nonsmeary; common fine and medium roots throughout; common fine tubular pores; 20 percent subangular gravel by volume, 30 percent subangular stones by volume; reduced monosulfides present; strongly acid (pH 5.5); clear wavy boundary (26 to 35 cm,10 to 14 in)
2Ab--53 to 65 cm (21 to 26 in); extremely gravelly sandy loam, very dark brown (10YR 2/2) moist; slightly hard, friable, nonsticky, nonplastic; nonsmeary; many very fine and many fine roots throughout; 16 percent subangular cobbles by volume, 45 percent gravel by volume; strongly acid (pH 5.5) clear wavy boundary (11 to 14 cm, 4 to 6 in)
2Cf--65 to 150 cm (26 to 59 in); extremely gravelly sandy loam, dark gray (5Y 4/1) broken face moist; massive; soft, very friable, nonsticky, nonplastic; nonsmeary; 16 percent subangular cobbles by volume, 45 percent gravel by volume; moderately acid (pH 5.8) (75 to 99 cm, 30 to 39 in)
TYPE LOCATION: North Copper River Soil Survey Area, Alaska; latitude 62.90629, longitude -144.12615, UTM 6978409.28 north and UTM 369298.20 east, zone 6, Datum WGS84.
RANGE IN CHARACTERISTICS:
Soil moisture regime: aquic
Soil temperature regime: gelic
Mean annual soil temperature: -4 to -2 degrees C. (25 to 38 degrees F)
Thickness of organic material: 10 to 19 cm (4 to 7 in)
Thickness of umbric epipedon: 30 to 42 cm (12 to 17 in)
Depth to redoximorphic depletions: 14 to 26 cm (6 to 10 in)
Depth to gelic material: 14 to 26 cm (6 to 10 in)
Depth to aquic conditions: 14 to 26 cm (6 to 10 in)
Depth to lithologic discontinuity: 14 to 26 cm (6 to 10 in)
Depth to permafrost: 51 to 75 cm (20 to 30 in)
Oi and Oe horizons:
Hue: 5YR or 10YR
Value: 2 to 3
Chroma: 1 to 3
Texture: peat, mucky peat
Organic matter: 60 to 90 percent
Reaction class: very strongly acid to strongly acid (pH 4.5 to 5.4)
A horizon:
Hue: 7.5YR or 10YR
Value: 2 to 3
Chroma: 1 to 3
Texture: silt loam
Sand: 30 to 45 percent
Silt: 50 to 66 percent
Clay: 3 to 9 percent
Rock fragments: 0 to 8 percent gravels
Organic matter: 4 to 8 percent
Reaction class: very strongly acid to strongly acid (pH 4.7 to 5.5)
2Bg horizon:
Hue: 2.5Y or 5Y
Value: 4 to 5
Chroma: 1 to 2
Texture: very stony sandy loam, very stony sandy clay loam
Sand: 59 to 71 percent
Silt: 3 to 24 percent
Clay: 16 to 26 percent
Rock fragments: 45 to 50 percent
Gravels: 10 to 25 percent
Stones: 25 to 35 percent
Organic matter: 0.5 to 3 percent
Reaction class: strongly acid to moderately acid (pH 5.1 to 6.0)
2Ab horizon:
Hue: 10YR or 2.5Y
Value: 2 to 3
Chroma: 1 to 3
Texture: very gravelly sandy loam, extremely gravelly sandy loam
Sand: 53 to 68 percent
Silt: 29 to 44 percent
Clay: 3 to 10 percent
Rock fragments: 44 to 61 percent
Gravels: 36 to 50 percent
Cobbles: 8 to 20 percent
Organic matter: 4 to 8 percent
Reaction class: strongly acid to moderately acid (pH 5.1 to 6.0)
2Cf horizon:
Hue: 2.5Y or 5Y
Value: 4 to 5
Chroma: 1 to 2
Texture: very gravelly sandy loam, extremely gravelly sandy loam
Sand: 53 to 68 percent
Silt: 29 to 44 percent
Clay: 3 to 10 percent
Rock fragments: 44 to 61 percent
Gravels: 36 to 50 percent
Cobbles: 8 to 20 percent
Organic matter: 0.5 to 2 percent
Reaction class: strongly acid to moderately acid (pH 5.5 to 6.0)
COMPETING SERIES: These are no competing series.
GEOGRAPHIC SETTING:
Elevation: 600 to 1600 meters (1969 to 5250 ft)
Parent material: organic material over silty loess over sandy and gravelly alluvium and/or sandy and gravelly colluvium
Landform: stream terraces
Slopes: 0 to 20 percent
Mean annual precipitation: 400 to 800 mm (16 to 31 in)
Mean annual air temperature: -4 to -2 degrees C. (25 to 28 degrees F)
Frost-free period: 89 to 103 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Haleycreek, Stibnite, and Tsina series.
Haleycreek soils are well drained with a cobbly sandy loam surface texture, have a mollic epipedon, lacks a lithic contact, and occur on hillslopes of mountains and river valleys.
Stibnite soils are well drained, 15 to 35 cm (6 to 14 in) cambic horizon, and occur in til lplains, mountains, kames and kettles.
Tsina soils are well drained, do not have umbric epipedons, and occur on mountain slopes above 800 m (2600ft) elevation.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class: poorly
Saturated Hydraulic Conductivity: high in the Oi, Oi2 and 2Ab horizons, moderately high in the A and 2Bg horizon, low in the 2Cf horizon
Permeability: moderately rapid in the Oi, Oi2 and 2Ab horizons, moderate in the A horizon, moderately slow in the 2Bg horizon, very slow in the 2Cf horizon.
Runoff: negligible
USE AND VEGETATION:
Use: wildlife habitat, recreation, and subsistence
Native vegetation: Biglow's sedge, resin birch, moss
DISTRIBUTION AND EXTENT: MLRA 228 Interior Alaska mountains.
Extent: limited
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Wasilla, Alaska
SERIES ESTABLISHED: North Copper River Soil Survey, Alaska, 2024.
REMARKS: Diagnostic features and horizons recognized in this profile include:
Particle-size control section: 41 to 116 cm (16 to 46 in)
Umbric epipedon: 16 to 53 cm (6 to 21 in) (A and 2Bg horizon)
Lithologic discontinuity: 22 to 150 cm (9 to 59 in) (2Bg, 2Ab, Cf horizons)
Aquic conditions: 22 to 65 cm (9 to 20 in) (2Bg and 2Ab horizons)
Reduced matrix: 22 to 65 cm (9 to 20 in) (2Bg and 2Ab horizons)
Gelic materials: 22 to 65 cm (9 to 20 in) (2Bg and 2Ab horizons)
Depth to permafrost: 65 to 150 cm (20 to 30 in) (Cf horizon)
ADDITIONAL DATA:
User pedon Id: 2023AK261326
National Cooperative Soil Survey
U.S.A.