LOCATION OCONALUFTEE NC+TN
Established Series
MLS:MSH:RAG; Rev. BPS
02/2022
OCONALUFTEE SERIES
The Oconaluftee series consists of very deep, well drained, moderately rapidly permeable soils on ridges and side slopes at the higher elevations in the Southern Blue Ridge mountains, MLRA 130B. They formed in residuum that is affected by soil creep in the upper part, and is weathered from low-grademetasedimentary rocks such as slate, thinly bedded metasandstone, and phyllite. Near the type location, mean annual temperature is 45 degrees F., and mean annual precipitation is 85 inches. Slope ranges from 8 to 95 percent.
TAXONOMIC CLASS: Fine-loamy, isotic, frigid Typic Humudepts
TYPICAL PEDON: Oconaluftee channery loam on a 64 percent northwest facing side slope at an elevation of 5052 feet--Forested (Colors are for moist soil.)
Oe--0 to 2 inches; partially decomposed organic litter and root mat.
A1--2 to 10 inches; black (10YR 2/1) channery loam; weak fine granular structure; very friable; many fine and medium roots; 25 percent phyllite and metasandstone channers and flagstones; common fine flakes of mica; extremely acid; clear wavy boundary. (6 to 12 inches thick)
A2--10 to 21 inches; dark brown (10YR 3/3) channery loam; weak medium granular structure; very friable; common fine and medium roots; 20 percent phyllite and metasandstone channers; common fine flakes of mica; strongly acid; clear wavy boundary. (4 to 14 inches thick; combined thickness of the A subhorizons is 10 to 20 inches.)
Bw--21 to 37 inches; dark yellowish brown (10YR 4/4) channery fine sandy loam; weak medium subangular blocky structure; very friable; few fine and medium roots; 20 percent phyllite and metasandstone channers; common fine flakes of mica; very strongly acid; gradual wavy boundary. (12 to 35 inches thick)
C--37 to 69 inches; olive brown (2.5Y 4/4), very pale brown (10YR 8/2), gray (10YR 6/1), and black (10YR 2/1) saprolite that has a channery fine sandy loam texture; weathered from interbedded phyllite and metasandstone; rock controlled structure; few fine and medium roots; 25 percent phyllite and metasandstone channers; common fine flakes of mica; strongly acid.
TYPE LOCATION: Jackson County, North Carolina; 7.8 miles northeast of Cherokee on U.S. Highway 19 to Soco Gap; 2.6 miles northwest on Blue Ridge Parkway; 400 feet west of Parkway at west end of Bunches Bald Tunnel.
RANGE IN CHARACTERISTICS: Solum thickness ranges from 30 to 60 inches. Depth to bedrock is more than 60 inches. The soil is extremely acid to strongly acid in the A horizon, and ranges from extremely acid to moderately acid in the other horizons. Content of mica flakes ranges from few to common. Content of rock fragments ranges up to 35 percent. They are dominantly of channer or flagstone size.
The A horizon has hue of 7.5YR or 10YR, value of 2 or 3, and chroma of 1 to 3. It is loam, fine sandy loam, or silt loam in the fine-earth fraction.
The AB horizon, where present, has hue of 7.5YR or 10YR, value of 3 or 4, and chroma of 2 to 4. It has the same textures as the A horizon.
The Bw horizon, and BC horizon if present, have hue of 7.5YR to 2.5Y, value of 4 to 6, and chroma of 3 to 8. They are loam, fine sandy loam, or silt loam in the fine-earth fraction.
The C horizon is saprolite weathered from low-grade metasedimentary rocks such as thinly bedded metasandstone, quartzite, phyllite, and slate. It is multicolored or variable in color and is loam, silt loam, fine sandy loam, sandy loam, loamy fine sand, or loamy sand in the fine-earth fraction.
COMPETING SERIES: These are the
Breakneck,
Burton,
Cataloochee,
Guyot,
Tanasee, and
Wayah series. Breakneck soils have a lithic contact at depths of 20 to 40 inches. Burton and Wayah soils formed in residuum and Tanasee in colluvium from high-grade metamorphic rocks and contain fragments of those rocks. Cataloochee and Guyot soils have paralithic contacts at depths of 20 to 40 and 40 to 60 inches repectively. Tanasee and Wayah soils have bedrock at depths greater than 60 inches.
GEOGRAPHIC SETTING: Oconaluftee soils are on strongly sloping to very steep side slopes and ridge tops in the Southern Appalachian Mountains. Elevation ranges from about 4,800 to 6,400 feet. On north and east aspects this soil may occur at somewhat lower elevations. Slope is commonly between 20 and 75 percent, but ranges from 8 to 95 percent. Oconaluftee soils formed in residuum that is affected by soil creep in the upper part, and is weathered from low-grade metasedimentary rocks such as thinly bedded metasandstone, quartzite, slate, and phyllite. Mean annual temperature is about 45 degrees F., and mean annual precipitation is about 85 inches near the type location. Moist atmospheric conditions are prevalent and fog is common in these high mountain areas.
GEOGRAPHICALLY ASSOCIATED SOILS: In addition to the competing
Breakneck,
Cataloochee, and
Guyot series, these include the
Chiltoskie,
Clingman,
Heintooga,
Horsetrough,
Pinnacle, and
Pullback series. Chiltoskie, Heintooga, and Horsetrough soils formed in colluvium. Heintooga soils are in a loamy-skeletal particle-size class. Horsetrough soils are in a sandy-skeletal particle-size class and are poorly drained. Clingman and Pinnacle soils are comprised of organic soil material. Pullback soils formed in residuum and have a lithic contact at less than 20 inches. Cataloochee soils have paralithic contact at 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; very little runoff where forest litter has not been disturbed or only partially disturbed; medium to very rapid runoff where litter has been removed; moderately rapid permeability.
USE AND VEGETATION: Nearly all of this soil is in forest. Common trees are northern red oak, black oak, American beech, yellow birch, black cherry, sugar maple, eastern hemlock, and yellow buckeye. In areas higher than 5,400 feet, red spruce and fraser fir are the dominant tree species. In many areas the trees are stunted due to wind and ice damage and a "windswept phase" is recognized. The understory species are serviceberry, striped maple, American chestnut sprouts, pin cherry, rhododendron, mountain-laurel, silverbell, blueberry, and flame azalea. Common forbs are hay-scented fern, wood fern, New York fern, Solomon's seal, yellow mandarin, and trillium. A small acreage is covered by heath balds vegetated with rhododendron, flame azalea, blueberry, hawthorn, and mountain ash.
DISTRIBUTION AND EXTENT: Southern Blue Ridge mountains, MLRA 130B of North Carolina, Tennessee and possibly Virginia. This series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Macon County, North Carolina, 1990.
REMARKS: The Oconaluftee series was formerly included with the Burton and Porters series. However, Burton soils have bedrock at depths of 20 to 40 inches below the surface, and Porters soils are mesic. Also, Burton and Porters soils formed from residuum weathered from felsic and high-grade metamprhic rocks such as granite, hornblende gneiss, and mica gneiss and contains fragments of those rocks.
The Oconaluftee series has the following diagnostic horizons:
Umbric epipedon - The zone from the mineral surface to 21 inches (Al and A2 Horizons.)
Cambic horizon - The zone from 21 to 37 inches below the surface (Bw horizon).
Revised 02/11-BPS: Taxonomic Classification -- 11th Keys, update competing and associated series, MLRA clarification
2/2022 revision: Oe had 2 to 0 inch depths, corrected to be 0 to 2 in horizon depths then added 2 inches to all horizon depths throughout the typical pedon. WJN
National Cooperative Soil Survey
U.S.A.