• This association includes boulderfield forests of the southern Appalachians, with abundant Betula alleghaniensis, but in habitats that allow for more diverse canopies, including other species such as Aesculus flava, Betula lenta, and Tilia americana var. heterophylla.
  • This community occurs in a cool, humid climate, on steep, rocky, northwest- to northeast-facing, middle to upper concave slopes, or in saddles between ridges, at moderate to high elevations (610-1,220 m [2,000-4,000 feet]) of the Blue Ridge and possibly ranging into the Cumberland Mountains and adjacent Ridge and Valley and Appalachian Plateau provinces.
  • It grows on bouldery talus and is often associated with small streams and seepage.
    
    
• The association described here generally occurs at lower elevations in less extreme environmental situations and lacks species characteristic of high elevations.
  • Similar Betula alleghaniensis-dominated forests occur on glaciated rocky slopes in the upper mid-Atlantic and in the northeastern United States.
  • The Betula alleghaniensis-dominated periglacial boulderfields of the southern Appalachian Mountains are distinguished from the northern forests by the occurrence of southern Appalachian endemic species, better developed shrub layers and slightly less species diversity.
  • This type is conceptually similar to ~Betula alleghaniensis / Ribes glandulosum / Polypodium appalachianum Forest (CEGL006124), which is more restricted to more extreme boulderfield situations at high elevations (1,370-1,615 m [4,500-5,300 feet]).
    
    
• Betula alleghaniensis in the canopy are often stunted and gnarled, with roots that may have grown to encircle the boulders.
  • The canopy is much more open than the surrounding forest and tree windthrow is common, leaving patches of exposed mineral soil and gaps in the canopy.
    
    
• A woody layer of shrubs and vines is usually well-developed.
  • Typical shrubs and vines which are more abundant in this type than in other associations in this alliance include Acer spicatum, Aristolochia macrophylla, Hydrangea arborescens, Parthenocissus quinquefolia, Ribes cynosbati, and Ribes rotundifolium. Dryopteris marginalis is often an abundant herb.
    
    
• Rooting opportunities for most herbaceous plants is limited because of the development of this community on periglacial boulderfields of blocky talus, thus herbaceous cover is only sparse to moderate.

• This forest has a canopy dominated by Betula alleghaniensis and/or Aesculus flava. Betula alleghaniensis in the canopy are often stunted and gnarled, with roots that may have grown to encircle the boulders.
  • Tree windthrow is common, leaving patches of exposed mineral soil and gaps in the canopy.
  • Other species in the canopy and subcanopy can include Tilia americana var. heterophylla, Fagus grandifolia, Acer saccharum, Acer spicatum, Tsuga canadensis, and Picea rubens.
    
    
• Shrub density is typically high but may vary between occurrences.
  • The shrub stratum is dominated by the tall shrub/sapling Acer spicatum and the short shrubs/saplings Hydrangea arborescens and Euonymus obovatus.
  • Ribes rotundifolium and Ribes cynosbati are conspicuous in the shrub stratum.
  • Other shrubs include Viburnum lantanoides, Sambucus racemosa var. pubens, and Rubus canadensis.
    
    
• Herb cover is moderate to dense, and herb strata tend to be diverse.
  • Herbs and mosses cover the rocks and boulders.
  • Dryopteris intermedia, Stellaria pubera, and the epiphyte Polypodium appalachianum are the most constant species in the stands sampled.
• Other common herbs include Ageratina altissima var. roanensis, Allium tricoccum, Angelica triquinata Arisaema triphyllum ssp. triphyllum, Eurybia chlorolepis, Actaea podocarpa, Diphylleia cymosa, Galium triflorum, Hydrophyllum canadense, Laportea canadensis, Melanthium parviflorum, Oxalis montana, Solidago curtisii, Tiarella cordifolia, and Trillium erectum.

• This community occurs in the Blue Ridge and possibly ranges into the Cumberland Mountains and adjacent Ridge and Valley and Appalachian Plateau provinces.

• This association was found on both the Cades Cove quadrangle and Mount Le Conte quadrangle, and it should occur elsewhere in the park on boulderfields below 5,000 feet elevation.
  
  
• It was sampled on the southwestern portion of the Cades Cove quadrangle, at the headwaters of Forge Knob Branch.
  
  
• On the southwestern portion of the Mount Le Conte quadrangle, this association was sampled southwest of Rocky Spur in the vicinity of Le Conte Creek and also southwest of Balsam Point.
  • This community was also sampled in the central portion of the Mount Le Conte quadrangle, in a north-facing ravine west of Trillium Gap.

• Global Conservation Status Rank: G3 (Last reviewed: 02 15 1999).
  
  
• This community is scattered throughout the high mountains but is fairly uncommon.
  • Unlike many other forest types in the Southern Appalachians, this community has not historically been threatened by logging as much as other types because of the stunted nature of the trees and the relative inaccessibility to loggers of these boulderfields.

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.

Chafin, L. G., and S. B. Jones, Jr. 1989. Community structure of two southern Appalachian boulderfields. Castanea 54:230-237.

Evans, M. 1991. Kentucky ecological communities. Draft report to the Kentucky Nature Preserves Commission. 19 pp.

Major, C. S., C. Bailey, J. Donaldson, R. McCoy, C. Nordman, M. Williams, and D. Withers. 1999. An ecological inventory of selected sites in the Cherokee National Forest. Tennessee Department of Environment and Conservation, Tennessee Division of Natural Heritage. Cost Share Agreement #99-CCS-0804-001. Nashville, TN.

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.

Pyne, M. 1994. Tennessee natural communities. Unpublished document. Tennessee Department of Conservation, Ecology Service Division, Nashville. 7 pp.

Rawinski, T. J. 1992. A classification of Virginia's indigenous biotic communities: Vegetated terrestrial, palustrine, and estuarine community classes. Unpublished document. Virginia Department of Conservation and Recreation, Division of Natural Heritage. Natural Heritage Technical Report No. 92-21. Richmond, VA. 25 pp.

Schafale, M. 1998b. Fourth approximation guide. High mountain communities. March 1998 draft. North Carolina 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.

Schafale, Mike P. Personal communication. Ecologist, North Carolina Department of Environment, Health, and Natural Resources, Division of Parks and Recreation, Natural Heritage Program, Raleigh.

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