Natural Resources
Conservation Service
Ecological site F128XY505WV
Thermic Low Stream Terrace Alluvium
Last updated: 5/14/2025
Accessed: 05/15/2026
-
Search
Major Land Resource Area or ecological site by name and/or ID.
PreviousSectionsNextGeneral information
Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
MLRA notes
Major Land Resource Area (MLRA): 128X–Southern Appalachian Ridges and Valleys
MLRA 128 falls into the East and Central Farming and Forest Region. This MLRA is in Tennessee (36 percent), Alabama (27 percent), Virginia (25 percent), and Georgia (12 percent). It makes up about 21,095 square miles (54,660 square kilometers).
Most of this MLRA is in the Tennessee Section of the Valley and Ridge Province of the Appalachian Highlands. The thin stringers in the western part of the area are mostly in the Cumberland Plateau Section of the Appalachian Plateaus Province of the Appalachian Highlands. A separate area of the MLRA in northern Alabama is in the Highland Rim Section of the Interior Low Plateaus Province of the Interior Plains. The western side of the area is dominantly hilly to very steep and is rougher and much steeper than the eastern side, much of which is rolling and hilly. Elevation ranges from 660 feet (200 meters) near the southern end of the area to more than 2,400 feet (730 meters) in the part of the area in the western tip of Virginia. Some isolated linear mountain ridges rise to nearly 4,920 feet (1,500 meters) above sea level.
The MLRA is highly diversified. It has many parallel ridges, narrow intervening valleys, and large areas of low, irregular hills. The bedrock in this area consists of alternating beds of limestone, dolomite, shale, and sandstone of early Paleozoic age. Ridgetops are capped with more resistant carbonate and sandstone layers, and valleys have been eroded into the less resistant shale beds. These folded and faulted layers are at the southernmost extent of the Appalachian Mountains. The narrow river valleys are filled with unconsolidated deposits of clay, silt, sand, and gravel.Ecological site concept
This site occurs primarily in alluvium on low stream terraces in the southern Ridge and Valley, MLRA 128. Most of it has been cleared for agriculture but native vegetation was likely mixed hardwoods.
Table 1. Dominant plant species
Tree (1) Quercus stellata
(2) Quercus albaShrub (1) Rubus
Herbaceous Not specified
Physiographic features
This site occurs primarily in alluvium on low stream terraces in the southern Ridge and Valley, MLRA 128.
Table 2. Representative physiographic features
Landforms (1) Terrace
(2) Stream terrace
(3) Alluvial fan
Flooding duration Long (7 to 30 days) Flooding frequency None to frequent Ponding duration Brief (2 to 7 days) Ponding frequency None to occasional Elevation 298 – 2299 ft Slope 0 – 15 % Ponding depth 0 – 15 in Water table depth 9 – 66 in Aspect Aspect is not a significant factor Climatic features
This area falls under the humid, mesothermal climate classification (Thornwaite, 1948). Precipitation is fairly evenly distributed throughout the year, with little or no water deficiency during any season. The average annual precipitation in most of this area is 45 to 55 inches. It increases to the south. Maximum precipitation occurs in midwinter and midsummer, and the minimum occurs in autumn. Most rainfall occurs as high-intensity, convective thunderstorms. Snowfall may occur in winter. Average annual temperatures range from 46 to 70 degrees F, increasing to the south. The freeze-free period averages 205 days and is longest in the southern part of the area and shortest at higher elevations to the north. The growing season corresponds to climate. Local climate can be variable and microclimates factor into the distribution of plants. In general, topographic features such as slope aspect, landform, steepness, and position of the ridges and valleys are important site variables in the distribution of vegetation across the landscape (Martin, 1989).
Table 3 Representative climatic features
Frost-free period (average) 190 days Freeze-free period (average) 220 days Precipitation total (average) 50 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
Figure 3. Annual precipitation pattern
Figure 4 Annual average temperature pattern
Climate stations used
-
(1) TALLADEGA [USC00018024], Talladega, AL
-
(2) HUNTSVILLE INTL AP [USW00003856], Madison, AL
-
(3) ROME [USC00097600], Rome, GA
-
(4) CHATTANOOGA LOVELL AP [USW00013882], Chattanooga, TN
-
(5) KNOXVILLE MCGHEE TYSON AP [USW00013891], Alcoa, TN
-
(6) MORRISTOWN RADIO WCRK [USC00406271], Morristown, TN
">Influencing water features
Lower areas are subject to flooding during periods of high rainfall in winter and early spring.<br />
Soil features
These soils formed primarily in alluvium on low stream terraces. The slopes range from 0 to 15 percent. They are moderately deep to very deep (20 to more than 60 inches) to bedrock, and are somewhat poorly to well drained. The available water capacity of these soils is moderate or high. The depth to a seasonal high water table ranges from 0.5 to more than 6 feet. The flooding frequency ranges from none to frequent. The ponding frequency ranges from none to occasional. The soil reaction ranges from extremely acid to moderately alkaline (pH from 3.5 to 8.4).
The soil series associated with this site are: Altavista, Barbourville, Beason, Bellamy, Bomar, Cane, Capshaw, Captina, Cedarbluff, Cloudland, Cobstone, Cotaco, Docena, Egam, Elk, Grasmere, Johnsburg, Landisburg, Lawrence, Leadvale, Locust, Monongahela, Nesbitt, Rome, Sequatchie, Shady, State, Statler, Stemley, Swafford, Taft, Tyler, Welchland, Whitwell, Wickham, Wolftever, and Woodmont.
Parent Material Kind: alluvium, colluvium, loess, marine deposits, residuum, and valley side alluvium.
Parent Material Origin: interbedded sedimentary; limestone and sandstone; limestone and shale; limestone, cherty; limestone, sandstone and shale; limestone, unspecified; metamorphic, unspecified; metasedimentary, unspecified; sandstone and shale; sandstone and siltstone; sedimentary, unspecified; shale, unspecified.Table 4. Representative soil features
Parent material (1) Alluvium – limestone and sandstone
(2) Colluvium – limestone and shale
(3) Loess – cherty limestone
Surface texture (1) Cobbly clay loam
(2) Gravelly fine sandy loam
(3) Stony loam
Drainage class Somewhat poorly drained to well drained Permeability class Slow to moderately rapid Soil depth 16 – 72 in Surface fragment cover <=3" 0 – 9 % Surface fragment cover >3" 0 – 9 % Available water capacity
(0-40in)2.7 – 8 in Soil reaction (1:1 water)
(0-40in)4.8 – 6.5 Subsurface fragment volume <=3"
(Depth not specified)0 – 32 % Subsurface fragment volume >3"
(Depth not specified)0 – 31 % Ecological dynamics
Most of these soils are cleared and used for growing hay, pasture, corn, tobacco, small grains, and vegetables. The native vegetation was likely mixed hardwoods with some pine. Where cultivated corn, cotton, small grain, soybeans, tobacco, peanuts, and truck crops are common. Where wooded, loblolly pine, sweetgum, red maple, yellow-poplar, white oak, southern red oak, water oak, American beech, and hickory are often present to varying degrees. Common understory plants include flowering dogwood, blueberry, sassafras, eastern redbud, eastern redcedar, winged elm, greenbrier, sourwood, southern bayberry (waxmyrtle), inkberry (bitter gallberry), summersweet clethra, honeysuckle, and poison ivy.
State and transition model
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1
Forested StateThis state approximates reference conditions. It varies widely across the MLRA from north to south. Generally, forests consist of some mixture of pine and hardwood species. Notable species include the hickories, red oak, white oak, chestnut oak, blackjack oak, shortleaf pine, longleaf pine, eastern white pine, and Virginia pine. Yellow poplar and the maples are also common. Because of the extent of disturbance on this site, reference conditions are approximations based on available historical descriptions and cannot be considered reliable.
State 2
Managed StateThis site is heavily managed. Pasture and hay are common land-uses. Crops can include corn, cotton, small grain, soybeans, tobacco, peanuts, and truck crops.
State 3
Abandoned StateThis state represents a managed site (E.g., pasture) that is no longer being managed and has been abandoned to succession. Species composition and overall health of this state will largely depend on the type and extent of previous land-use disturbance. It is likely that non-native invasive plants will be introduced to this state. Other native early successional species will also be represented but will naturally fall out over time as the site ages. In some cases, early successional habitat is desirable (E.g., for some wildlife species). If that is the case, then it must be managed to be maintained. Management practices should be locally determined based on the native species composition, presence of non-native invasive plants and landowner goals.
Transition T1A
State 1 to 2Tree clearing and establishment of agricultural crop. Practices vary widely based on the intent of management.
Transition T2A
State 2 to 3Natural succession after management ceases. Sometimes this includes invasion by undesirable non-native plants.
Restoration pathway R3B
State 3 to 1If few or no invasive, non-native plant species are present this site will naturally regenerate to the forested state. In some cases, herbicide or mechanical control might be needed to select desirable species if the future goal is timber management. In some cases, tree planting might be merited.
Restoration pathway R3A
State 3 to 2Brush clearing where needed, application of herbicides where needed, management for desired agricultural outcome. Where native grasslands/prairies are the management objective, different techniques should be employed. Site preparation and seeding mixtures would likely be needed. If early successional habitat is the management goal, practices such as brush clearing, herbicide application where needed and prescribed fire might be necessary to maintain this condition.
Additional community tables
Interpretations
Supporting information
Other references
DeSelm, Hal. 1989 – 2009. Natural Terrestrial Vegetation of Tennessee (Vegetation Plot Data). Unpublished raw data. http://treeimprovement.utk.edu/DeSelmData/DataDSC.htm
Griffith, G.E., Omernik, J.M., and Azevedo, S.H., 1997, Ecoregions of Tennessee: Corvallis, Oregon, U.S. Environmental Protection Agency EPA/600R-97/022, 51 p.
Martin, William H. 1989. Forest patterns in the Great Valley of Tennessee. Journal of the Tennessee Academy of Science 64(3): 137 – 143.
Natureserve. 2016. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.0. NatureServe, Arlington, VA. U.S.A. Available http://explorer.natureserve.org.
Thornthwaite, Charles W. 1948. An approach toward a rational classification of climate. Geographical Review 38(1): 55-94.
United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land Resource Regions and Major Land Resource Areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.
Vegetation plot data. 2015. Retrieved from: http://vegbank.org/vegbank/index.jsp
Vegetation community description. 2015. Retrieved from: http://www.basic.ncsu.edu/segap/Contributors
Belinda Esham Ferro
Approval
Matthew Duvall, 5/14/2025
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
Author(s)/participant(s) Contact for lead author Date 05/15/2026 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
-
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
-
Perennial plant reproductive capability:
Print Options
Sections
Font
AAAAOther
PrintThe Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
Accessibility statement