Common (Translated Scientific) Name: Red Maple - Blackgum - Sweetgum Seepage Forest Group
Colloquial Name: Central Interior-Appalachian Seepage Swamp
Hierarchy Level: Group
Type Concept: This group of deciduous acidic seepage swamp forest communities is found primarily in two distinctive cool temperate regions of eastern North America. One of these constitutes the broadly conceived Appalachian region, including the southern Piedmont, the Cumberland Plateau and Ridge and Valley regions, parts of the Central Appalachians, and portions of the Southern Blue Ridge including the flat metasedimentary upland surfaces of Chilhowee Mountain, Tennessee. Some of the associations from this region range peripherally into the adjacent Interior Low Plateau and coastal plains, but these areas are not part of the core area. The other part of the group's range includes the unglaciated Interior Low Plateau from Alabama to Kentucky, and the Ouachitas and Ozarks of Arkansas and Oklahoma. These wetland forests generally occur where the substrate is saturated to the surface for extended periods during the growing season, but where surface water is seldom present for more than short periods of time. For example, in the Cumberland Plateau, stands most often occur in streamhead swales or on broad sandstone ridges where soils are sandy and saturated due to a combination of perched water table and seepage flow. Examples range in condition from open woodlands to forests. Typical woody species include Acer rubrum, Nyssa sylvatica, Liriodendron tulipifera, Liquidambar styraciflua, Ilex opaca var. opaca, Oxydendrum arboreum, and Viburnum nudum. In the Piedmont, vegetation is variable within and among examples. Included are seepage-fed wetlands on gentle slopes, with substantial seepage flow and which may be influenced by wildland fire. In the Ouachita Mountains of central Arkansas, as well as on Mount Magazine and in the Ozarks, examples may be found along the bottom slopes of smaller valleys, as well as in the upper riparian zones of larger creeks, sometimes extending upslope along small ephemeral drainages. The soil remains saturated to very moist throughout the year. The vegetation is typically forested with highly variable canopy composition. Acer rubrum var. trilobum, Nyssa sylvatica, Liquidambar styraciflua, and Quercus alba are common and typical. Other canopy species may include Fagus grandifolia and Magnolia tripetala. Canopy coverage can be moderately dense to quite open. The subcanopy is often well-developed and characteristically includes Ilex opaca var. opaca, Magnolia tripetala, Carpinus caroliniana, and Ostrya virginiana. Individual occurrences of these forests tend to be small in extent and can provide habitat for rare plant and animal species.
Diagnostic Characteristics: Examples of this group are characterized by their hydrologic setting, with constant or seasonal seepage providing moisture to a distinct suite of plant species. Stands are characterized by a combination of trees that may include Acer rubrum, Ilex opaca var. opaca, Liquidambar styraciflua, Liriodendron tulipifera, and Nyssa sylvatica.
Rationale for Nominal Species or Physiognomic Features: Acer rubrum, Nyssa sylvatica, and Liquidambar styraciflua occur in a variety of upland or wetland habitats and are wide-ranging species. This makes them less than completely effective nominal species. While they are the most characteristic species of the associations assigned to this group, they are not differential species. Liquidambar styraciflua is included as an indicator of the relatively southern range of the group relative to ~Northern Conifer & Hardwood Acidic Swamp Group (G045)$$.
Classification Comments: Vegetation of this group is related floristically, but occurs in a variety of wet to saturated environments, including forested seeps that have a fire-intolerant flora and occur in lower topographic settings, and streamhead seeps which occur along drainages. These sites are generally saturated without having long periods with standing water as floodplain pools do. In the Piedmont, the differences are not as sharp and the range of variation is smaller within each variant type. Piedmont seepage wetlands are separated from vegetation of equivalent Southern Appalachian examples by floristic differences. In the Cumberlands, examples range in condition from open woodlands to forests. There may be undescribed associations in the Interior Low Plateau of Kentucky ("Shawnee Hills").
Similar NVC Types:
G045 Laurentian-Acadian-Appalachian Acidic Swamp, note:
G597 Central Hardwood Flatwoods & Swamp Forest, note:
G599 Central Interior-Appalachian Open Depression Pond, note:
G667 Northeastern Forest Vernal Pool, note:
Physiognomy and Structure: Stands are composed of broad-leaved deciduous trees. They vary in canopy closure with fire frequency. In the current landscape, most are closed-canopy forests.
Floristics: Examples of this vegetation are generally patchy and heterogeneous in structure. The canopy coverage is variable, depending both on the degree of wetness and the frequency of fire. In more open examples, well-developed shrub or herb layers are almost always present. The trees are often not very distinctive, consisting of widespread wetland species, such as Acer rubrum (frequently recorded as var. triloba), Fraxinus pennsylvanica, and Nyssa sylvatica, or of non-wetland species shared with adjacent communities, including Liquidambar styraciflua and Liriodendron tulipifera. The subcanopy is often well-developed and may include Carpinus caroliniana and Ilex opaca var. opaca. The shrub layer normally consists of wetland species, including Alnus serrulata and Viburnum nudum. In addition, Vaccinium spp. and other ericaceous species are often common. The herb layer is quite variable. Large wetland ferns such as Osmunda cinnamomea and Osmunda regalis var. spectabilis are often prominent. Various wetland grasses, sedges, and rushes may be abundant, and forbs such as Boehmeria cylindrica, Impatiens capensis, Rudbeckia laciniata, and Saururus cernuus are also often prominent. Some examples have substantial amounts of Sphagnum spp. In the Piedmont, plants such as Cyrilla racemiflora, Sarracenia flava, Sarracenia purpurea, and Smilax laurifolia, which are more characteristic of the coastal plain, may be present. There is some floristic variation with latitude and elevation, with southern and lower-elevation associations containing Magnolia virginiana and/or Nyssa biflora, which are more typical of the coastal plain. An Appalachian association has the canopy tree Pinus rigida. Some rich Ozark examples may contain Fagus grandifolia and Magnolia tripetala. Some stands are more open due to fire frequency, windthrow, or other disturbance. These are more likely to contain noteworthy herbaceous plant species (e.g., Cypripedium kentuckiense, Platanthera spp.).
Dynamics: The presence of seepage is the primary determinant of this group. Long-term droughts that affect seepage flow presumably have an effect. Canopy dynamics are not well-known and potentially may vary substantially over short distances in response to wetness. Wetness clearly limits recruitment of most tree and shrub seedlings to drier microsites in the wettest examples. Fire is an important influence in some examples. Long-term geomorphic processes may be important in these systems. Headward erosion by small streams, or meandering by larger stream channels, sometimes drains seeps and eliminates the wetland vegetation. Stands are often left undisturbed when surrounding forests are logged. Effects of logging on water infiltration or surface flow may have significant indirect effects.
Environmental Description: Vegetation of this group occurs in small patches where relatively constant or seasonal seepage water creates wetland conditions. Seepage commonly occurs at the base of slopes on the edge of bottomlands or in headwaters of small streams. Others occur on gently sloping hillsides where impermeable soils and slope force shallow groundwater to the surface. The soil is seasonally to permanently saturated, but has no substantial standing water. Climate: The climate is cool temperate. About 100-150 cm (40-60 inches) of rainfall is spread throughout the year. Many years, short-term drought occurs in the late summer or fall (e.g., October). Soil/substrate/hydrology: Seepage water creates wetland conditions at the base of slopes on the edge of bottomlands or in headwaters of small streams. On gently sloping hillsides, impermeable soils and slope force shallow groundwater to the surface. The soil is seasonally to permanently saturated, but has no substantial amount of standing water. Soils may be mineral, but may have muck or peaty component to them.
Geographic Range: Vegetation of this group is found primarily in two distinctive cool temperate regions of eastern North America. One of these constitutes the broadly conceived Appalachian region, including the southern Piedmont, the Cumberland Plateau and Ridge and Valley regions, parts of the Central Appalachians, and portions of the Southern Blue Ridge including the flat metasedimentary upland surfaces of Chilhowee Mountain, Tennessee. Some of the associations from this region range peripherally into the adjacent Interior Low Plateau and coastal plains, but these areas are not part of the core area. The other part of the group's range includes the unglaciated Interior Low Plateau from Alabama to Kentucky and the Ouachitas and Ozarks of Arkansas and Oklahoma.
States/Provinces: AL, AR, GA, KY, MD, MO, NC, OK, SC, TN, VA?, WV
|US Forest Service Ecoregions (2007)|
Southeastern Mixed Forest Province
Confident or certain
Southern Appalachian Piedmont Section
Confident or certain
Omernik Ecoregions: 36:C, 36b:C, 36d:C, 36e:?, 38:C, 38a:C, 38b:C, 39:C, 39a:C, 39b:C, 39c:C, 39d:C, 45:C, 45a:C, 45b:C, 45c:C, 45d:C, 45e:C, 45f:C, 45g:C, 45h:C, 45i:C, 64:C, 64a:C, 64b:C, 64c:C, 64d:C, 66:C, 66a:C, 66e:C, 66m:C, 67:C, 67f:P, 67g:P, 67h:C, 67i:C, 68:C, 68a:C, 68b:P, 68c:P, 68d:C, 68e:P, 68f:C
Confidence Level: Low
Confidence Level Comments:
Synonomy: >< IIA9a. Forested Mountain Seep (Allard 1990)
Concept Author(s): M. Pyne and S.C. Gawler, in Faber-Langendoen et al. (2011)
Author of Description: M. Pyne and S.C. Gawler
Version Date: 19May2015
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- Evans, M. 1991. Kentucky ecological communities. Draft report to the Kentucky Nature Preserves Commission. 19 pp.
- Faber-Langendoen, D., J. Drake, S. Gawler, M. Hall, C. Josse, G. Kittel, S. Menard, C. Nordman, M. Pyne, M. Reid, L. Sneddon, K. Schulz, J. Teague, M. Russo, K. Snow, and P. Comer, editors. 2010-2017a. Divisions, Macrogroups and Groups for the Revised U.S. National Vegetation Classification. NatureServe, Arlington, VA. plus appendices. [in preparation]
- Foti, T., compiler. 1994b. Natural vegetation classification system of Arkansas, draft five. Unpublished document. Arkansas Natural Heritage Commission, Little Rock. 8 pp.
- NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Central Databases. NatureServe, Arlington, VA.
- 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.
- Schafale, Mike P. Personal communication. Ecologist, North Carolina Department of Environment, Health, and Natural Resources, Division of Parks and Recreation, Natural Heritage Program, Raleigh.