• This is a low-elevation montane or submontane alluvial forest which is found on large alluvial flats and high terraces along large rivers (e.g., Little Pigeon River) or on small, disturbed flats along medium-sized perennial streams.
  • It is found at lower elevations in the southern fringes of the Southern Blue Ridge Province, or in the adjacent Piedmont and Southern Ridge and Valley.
  • It often occurs on sites that were formerly cleared for farming or settlement.
  • Soils are typically deep, loamy silts but can have large rocks and cobbles.
  • In the Great Smoky Mountains, the mean elevation of samples is 1,680 feet, ranging from 1,480-1,900 feet.
  • It would be possibly expected at lower elevations as well, especially in the adjacent ecoregions.
    
    
• This forest has an open to closed canopy dominated by Liquidambar styraciflua and Liriodendron tulipifera, often with Platanus occidentalis.
  • It is distinguished from other kinds of Montane Alluvial Forests by the dominance or relatively higher importance of Liquidambar styraciflua in its stands, and by its habitat on larger, lower-elevation, riverine situations.
  • Platanus is characteristic, but not necessarily dominant in stands of this association. In habitats with a more calcareous influence in the substrate, Juglans nigra may have a higher relative importance or even be codominant.
    
    
• The subcanopy is absent to well-developed.
  • Typical dominants are Carpinus caroliniana, Cornus florida, and Acer rubrum.
    
    
• The shrub stratum is absent to moderately dense.
  • Rhododendron maximum and Tsuga canadensis are the most common shrubs, although other species can be present.
    
    
• Herbaceous cover is often absent or sparse, with ground cover dominated by litter and duff.
  • On smaller streams, near open fields or where animal grazing is evident, herbaceous cover can approach 100% cover.
  • Species often present with high coverage include Amphicarpaea bracteata, Ageratina altissima var. altissima, Dichanthelium boscii, Thelypteris noveboracensis, and Toxicodendron radicans.
  • Stands found on small, disturbed flats along medium-sized perennial streams may contain patches of Xanthorhiza simplicissima.
  • The exotic grass Microstegium vimineum may have high cover in some stands.

• This forest has an open to closed canopy dominated by Liquidambar styraciflua and Liriodendron tulipifera, often with Platanus occidentalis.
  • Other minor species that are variably present in the canopy include Acer rubrum, Fraxinus americana, Juglans nigra, Pinus virginiana, Prunus serotina, Robinia pseudoacacia, Tilia americana var. heterophylla, and Ulmus americana.
    
    
• The subcanopy is absent to well-developed.
  • Typical dominants are Carpinus caroliniana, Cornus florida, and Acer rubrum.
  • Other species that can be present in the subcanopy include Betula alleghaniensis, Betula lenta, Tsuga canadensis, Juglans cinerea, Halesia tetraptera var. monticola, Acer pensylvanicum, Acer saccharum, Amelanchier laevis, Oxydendrum arboreum, and Prunus serotina.
    
    
• The shrub stratum is absent to moderately dense.
  • Rhododendron maximum and Tsuga canadensis are the most common shrubs, although other species can be present.
    
    
• Herbaceous cover is often absent or sparse, with ground cover dominated by litter and duff.
  • On smaller streams, near open fields or where animal grazing is evident, herbaceous cover can approach 100% cover.
  • Species often present with high coverage include Amphicarpaea bracteata, Dichanthelium boscii, Microstegium vimineum, Thelypteris noveboracensis, and Toxicodendron radicans.
  • Other common species include Arisaema triphyllum, Asplenium platyneuron, Eurybia divaricata, Carex spp. (e.g., Carex digitalis, Carex intumescens, Carex laxiflora, Carex plantaginea, Carex platyphylla, Carex retroflexa, Carex swanii, Carex torta), Dichanthelium spp. (e.g., Dichanthelium commutatum, Dichanthelium boscii, Dichanthelium sphaerocarpon), Houstonia serpyllifolia, Laportea canadensis, Mitchella repens, Parthenocissus quinquefolia, Polystichum acrostichoides, Prenanthes spp., Sanicula canadensis, and Verbesina alternifolia.

• This community was defined from the western fringe of the Southern Blue Ridge, but is also found at lower elevations in the southern fringes of the Southern Blue Ridge Province, and probably in the adjacent Piedmont and Southern Ridge and Valley.

• Sweetgum-dominated alluvial forests were sampled from both the Cades Cove quadrangle and Mount Le Conte quadrangle and are likely in other areas of the Park.
  
  
• They were sampled from the northern portion of the Mount Le Conte quadrangle, on the floodplain of the Little Pigeon River, northeast of the Greenbrier Campground and also near the confluence with Ted's Branch; on the Lower Little Pigeon River, near the northern Park boundary; and on the broad floodplain of Dud's Branch, near Dudley Creek.
  
  
• On the Cades Cove quadrangle this community was sampled in the northern half of the quadrangle, off the Cades Cove Loop Road, in the vicinity of Mills Creek and Abrams Creek and along Rowans Branch; and just south of the Loop Road, in the vicinity of Mill Creek and Forge Creek Road.

• Global Conservation Status Rank: GNR (Last reviewed: 03 22 1999).
  
  
• The conservation status of this community has not yet been assessed.

Allard, D. J. 1990. Southeastern United States ecological community classification. Interim report, Version 1.2. The Nature Conservancy, Southeast Regional Office, Chapel Hill, NC. 96 pp.

NatureServe Ecology - Southeastern United States. No date. Unpublished data. NatureServe, Durham, NC.

Newell, C. L., and R. K. Peet. 1995. Vegetation of Linville Gorge Wilderness, North Carolina. Unpublished report. to USDA Forest Service. University of North Carolina, Department of Biology, Chapel Hill. 211 pp.

Patterson, K. D., C. J. Ulrey, and J. Drake. 1999. Vegetation classification of Great Smoky Mountains National Park: Cades Cove and Mount Le Conte quadrangles. Unpublished report submitted to BRD-NPS Vegetation Mapping Program. The Nature Conservancy, Chapel Hill, NC.

Peet, R. K., T. R. Wentworth, M. P. Schafale, and A.S. Weakley. 2002. Unpublished data of the North Carolina Vegetation Survey. University of North Carolina, Chapel Hill.

Southeastern Ecology Working Group of NatureServe. No date. International Ecological Classification Standard: International Vegetation Classification. Terrestrial Vegetation. NatureServe, Durham, NC.