Natural Resources
Conservation Service

Ecological site PX136X00X600

Flood Plain Forest, Very Wet

Accessed: 12/22/2024

Home / Esd catalog / MLRA 136X / Ecological site PX136X00X600

USC

Metric

General 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): 136X–Southern Piedmont

This area is in North Carolina (29 percent), Georgia (27 percent), Virginia (21 percent), South Carolina (16 percent), and Alabama (7 percent). It makes up about 64,395 square miles (166,865 square kilometers). (Ag Bulletin 296)

The northeast-southwest trending Piedmont ecoregion comprises a transitional area between the mostly mountainous ecoregions of the Appalachians to the northwest and the relatively flat coastal plain to the southeast. It is a complex mosaic of Precambrian and Paleozoic metamorphic and igneous rocks with moderately dissected irregular plains and some hills. (EPA Ecoregions descriptions)

ADD APPROPRIATE ECOREGION DESCRIPTION(S)

Classification relationships

A PROVISIONAL ECOLOGICAL SITE is a conceptual grouping of soil map unit components within a Major Land Resource Area (MLRA) based on the similarities in response to management. Although there may be wide variability in the productivity of the soils grouped into a Provisional Site, the soil vegetation interactions as expressed in the State and Transition Model are similar and the management actions required to achieve objectives, whether maintaining the existing ecological state or managing for an alternative state, are similar. Provisional Sites are likely to be refined into more precise group during the process of meeting the APPROVED ECOLOGICAL SITE DESCRIPTION criteria.

This PROVISIONAL ECOLOGICAL SITE has been developed to meet the standards established in the National Ecological Site Handbook. The information associated with this ecological site does not meet the Approved Ecological Site Description Standard, but it has been through a Quality Control and Quality Assurance processes to assure consistency and completeness. Further investigations, reviews and correlations are necessary before it becomes an Approved Ecological Site Description.

Ecological site concept

This ecological site supports vegetation along small streams and narrow middle-order streams. Soils are relatively acidic and relatively well-drained. Topographic differences from one floodplain to another, such as gradient and height above the creek, as well as floodplain microtopography (i.e., depositional landforms such as natural levees and sloughs) may influence the variation of vegetation. They occur both on narrow floodplains of small streams and on large rivers where the floodplain is narrowed by bedrock. These are drainageways with limited differentiation of communities by depositional landforms, with natural levees, backswamps, and sloughs absent or too small to be recognized as occurrences of separate communities.

Table 1. Dominant plant species

Tree	(1) Liquidambar styraciflua (2) Liriodendron tulipifera
Shrub	(1) Lindera benzoin
Herbaceous	(1) Arisaema triphyllum

Legacy ID

F136XY600NC

Download full description

Physiographic features

Most of MLRA 136 is in the Piedmont Upland Section of the Piedmont Province of the Appalachian Highlands. A very small part of the MLRA, in central North Carolina, is in the Atlantic Plain Division. A very small part in the Roanoke, Virginia, area is on the eastern edge of the Blue Ridge Province of the Appalachian Highlands. This MLRA is a rolling to hilly upland with a well-defined drainage pattern. The original plateau has been dissected by streams, resulting in narrow to fairly broad upland ridgetops and short slopes. Valley floors are very narrow, and stream terraces are minor. Elevation ranges from 330 to 1,310 feet (100 to 400 m), increasing gradually from south to north.

Geology:
Precambrian and Paleozoic metamorphic and igneous rocks underlie almost all of this MLRA. The dominant metamorphic rock types include biotite gneiss, schist, slate, quartzite, phyllite, and amphibolite. The dominant igneous rock types are granite and metamorphosed granite. Some gabbro and other mafic igneous rocks also occur, and diabase dikes are not uncommon. The Carolina Slate terrane occurs just east of an imaginary centerline in this MLRA. It consists of metamorphic rocks with some metavolcanics and metasediments. Scattered graben basins, which are bounded by faults where the ground between the faults has dropped down, occur from South Carolina to south of Charlottesville and Richmond, Virginia. These basins have Triassic and Jurassic siltstone, shale, sandstone, and mudstone. River valleys have recent alluvium and few terraces.

Figure 1. EPA Level IV Ecoregions map.

Table 2. Representative physiographic features

Landforms	(1) Drainageway (2) Flood plain
Flooding duration	Brief (2 to 7 days)
Flooding frequency	None to frequent
Ponding duration	Brief (2 to 7 days) to long (7 to 30 days)
Ponding frequency	None to occasional
Slope	0 – 3%
Water table depth	0 – 38 cm
Aspect	Aspect is not a significant factor

Climatic features

This ecological site occurs in the thermic temperature regime for MLRA 136. The thermic soil temperature regime has mean annual soil temperatures of 15° C or more, but less than 22 °C; and a difference between mean summer and mean winter soil temperatures of greater than 5 °C at 50 cm below the surface.

The average annual precipitation is 45 to 60 inches (1,145 to 1,525 millimeters) and is as much as 75 inches (1,905 millimeters) in a small, high-elevation area in northeastern Georgia. The precipitation generally is evenly distributed throughout the year. It is lowest in autumn. Most of the rainfall occurs as high-intensity, convective thunderstorms during the growing season. Significant moisture also comes from the movement of warm and cold fronts across the MLRA from November to April. High amounts of rain can occur during hurricanes at the same time of the year. Snowfall typically is light. The average annual temperature is 53 to 64 degrees F (12 to 18 degrees C). The freeze-free period averages 230 days and ranges from 185 to 275 days. Both the mean annual temperature and length of the freeze-free period increase from north to south and with decreasing elevation.

Table 3. Representative climatic features

Frost-free period (average)	195 days
Freeze-free period (average)	225 days
Precipitation total (average)	1,321 mm

Bar

Line

Figure 2. Monthly precipitation range

Bar

Line

Figure 3. Monthly average minimum and maximum temperature

Figure 4. Annual precipitation pattern

Figure 5. Annual average temperature pattern

Climate stations used

(1) WEST POINT [USC00099291], Lanett, GA
(2) SIMMS WTP [USC00387885], Chesnee, SC
(3) CHASE CITY [USC00441606], Chase City, VA
(4) HICKORY FAA AP [USW00003810], Hickory, NC
(5) CHARLOTTE DOUGLAS AP [USW00013881], Charlotte, NC
(6) COVINGTON [USC00092318], Covington, GA
(7) EXPERIMENT [USC00093271], Griffin, GA
(8) ATHENS BEN EPPS AP [USW00013873], Athens, GA
(9) COLUMBUS METRO AP [USW00093842], Columbus, GA
(10) ASHLAND 3 ENE [USC00010369], Ashland, AL
(11) ROCKFORD 3 ESE [USC00017020], Rockford, AL
(12) DALLAS 7 NE [USC00092485], Dallas, GA
(13) GAINESVILLE [USC00093621], Gainesville, GA
(14) MILLEDGEVILLE [USC00095874], Milledgeville, GA
(15) SALISBURY [USC00317615], Salisbury, NC
(16) SILER CITY 2 N [USC00317924], Siler City, NC
(17) CARROLLTON [USC00091640], Carrollton, GA
(18) ALBEMARLE [USC00310090], Albemarle, NC
(19) ASHEBORO 2 W [USC00310286], Asheboro, NC
(20) CHESNEE 7 WSW [USC00381625], Chesnee, SC
(21) CLEMSON UNIV [USC00381770], Clemson, SC
(22) GREENWOOD [USC00383754], Greenwood, SC
(23) NEWBERRY [USC00386209], Newberry, SC
(24) CROZIER [USC00442142], Maidens, VA

Soil features

This ecological site occurs within the thermic soil temperature regime, which is defined as: The mean annual soil temperature is 15 degrees C or higher but lower than 22 degrees C, and the difference between mean summer and mean winter soil temperatures is 6 degrees C. Dominant soil components are the Wehadkee soil series. These soils meet the definition of a hydric soil.

Table 4. Representative soil features

Surface texture	(1) Loam (2) Silt loam
Drainage class	Somewhat poorly drained to very poorly drained
Permeability class	Moderate to slow
Soil depth	152 cm
Available water capacity (0-101.6cm)	10.16 – 22.86 cm
Calcium carbonate equivalent (0-101.6cm)	0%
Electrical conductivity (0-101.6cm)	0 mmhos/cm
Sodium adsorption ratio (0-101.6cm)	0
Soil reaction (1:1 water) (0-101.6cm)	4.5 – 6.5
Subsurface fragment volume <=3" (Depth not specified)	0 – 5%

Ecological dynamics

Dynamics: Flooding, deposition and loss of alluvial material, and windthrow result in a constantly changing environment. Floods disturb vegetation by washing away plants and soil. In more severe floods, small parts of the forest may be eroded or completely washed away. The tendency of streamside trees to lean toward the river has both positive and negative consequences. Leaning trees gain access to higher light levels that potentially increase growth rates, but because a greater part of their trunks are immersed in fast running water during heavy floods, they are particularly susceptible to being uprooted and washed away. Prolonged flooding can also stress or kill flood plain trees. Most flood plain trees can tolerate short periods of flooding, but few species can handle prolonged flooding during the growing season.
Flood plains are continually dynamic with the deposition of new sediment and the loss of old sediment. Sandbars and mudflats form on the inside curves or rivers, and regular flooding deposits alluvial material. Flood plain soils consist of alluvium that can range from 15 to 250 feet thick. Heavy mud deposition during the growing season kill herbaceous plants and the seedlings and saplings of woody plants.
Storms, tornadoes, and occasional hurricanes can cause considerable wind damage. Shallow root systems allow flood plain trees to use the uppermost soil region, where anaerobic conditions are less likely, but make them more vulnerable to windthrow. Trunks of wind-toppled trees often lie scattered across flood plains. The openings created by downed trees increase the abundance and diversity of herbaceous plants and facilitate forest regeneration.
Today, flood plain forests exist in various stages of succession following tree removal. Very few tracts with old-growth trees are known.

State and transition model

Custom diagram

Standard diagram

Figure 6. state and transition model

More interactive model formats are also available. View Interactive Models

Supporting information

Other references

Edwards, L., J. Ambrose, and L.K. Kirkman. 2013. The Natural Communities of Georgia. The University of Georgia Press. Athens and London.

Environmental Protection Agency (EPA). 2004. Level III and IV Ecoregions of EPA Region 4. U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory. Western Ecology Division, Corvallis, Oregon. Scale 1:2,000,000.

Fleming, Gary P. and Karen D. Patterson. 2013. Natural Heritage Report 13-16. Natural Communities of Virginia: Ecological Groups and Community Types. Virginia Department of Conservation and Recreation, Division of Natural Heritage, Richmond, Virginia. 36 pages.

NatureServe. 2013. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer. (Accessed May 24, 2013).

Nelson, John B. 1986. The natural Communities of South Carolina: Initial Classification and Description. South Carolina Wildlife and Marine Resources Department.

Schafale, M. P. 2012. Classification of the natural communities of North Carolina, 4th Approximation. North Carolina Department of Environment, Health, and Natural Resources, Division of Parks and Recreation, Natural Heritage Program, Raleigh.

Schafale, M. P., and A. S. Weakley. 1990. Classification of the natural communities of North Carolina. Third approximation. North Carolina Department of Environment, Health, and Natural Resources, Division of Parks and Recreation, Natural Heritage Program, Raleigh. 325 pp.

Skeen, J. N., M. E. B. Carter, and H. L. Ragsdale. 1980. Yellow-poplar: The Piedmont case. Bulletin of the Torrey Botanical Club 107:1-6.

Spira, Timothy P. 2011. Wildflowers and Plant Communities of the Southern Appalachian Mountains and Piedmont. The University of North Carolina Press. Chapel Hill.

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.

Wharton, C.H. 1978. The natural environments of Georgia. Bulletin 114. Georgia Department of Natural Resources. Atlanta.Schafale, M. P. 2012. Classification of the natural communities of North Carolina, 4th Approximation. North Carolina Department of Environment, Health, and Natural Resources, Division of Parks and Recreation, Natural Heritage Program, Raleigh.

United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land Resource Regions and Major Land Resource Areas of the Unites States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296.

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
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:

Download reference sheet

Search

Natural ResourcesConservation Service