Physiognomy and Structure: These are dense shrubland communities found at the highest elevations of the Southern Appalachians.

Floristics: Examples of this vegetation consist of dense shrubs, particularly Rhododendron catawbiense, but substantial examples are also dominated by Kalmia latifolia, Rhododendron carolinianum, or a mixture of other shrubs, including Corylus cornuta, Gaylussacia baccata, Leiophyllum buxifolium, Pieris floribunda, Prunus pensylvanica, Sorbus americana, and Vaccinium corymbosum. One large example, dominated by Alnus viridis ssp. crispa, is also included here. Large areas have also become dominated by Rubus allegheniensis, possibly with other brambles (Rubus canadensis, Rubus idaeus ssp. strigosus) and by mixtures of native grasses with exotic pasture grasses (e.g., Phleum pratense). Heath balds may contain sparse stunted trees barely larger than the shrub canopy.

Dynamics:  The dynamics that created and maintain this vegetation are the subject of a yet unresolved debate. In particular, the relationship between shrub balds and grassy balds is not fully understood. Some interpretations suggest that shrub balds are simply degraded grassy balds, but the situation may be more complicated. On the one hand, most grassy bald occurrences show a strong tendency to succeed to shrub or forest vegetation under present conditions, suggesting that some important maintenance process has been lost. Grazing by native herbivores (elk and bison) and periodic fire have both been suggested as natural mechanisms to keep out woody vegetation. Exposure to wind, snow, ice, and heavy rainfall also retard succession to forest. The presence of shade-intolerant disjunct herb species in some suggests even greater age. Some areas of the spruce-fir system degraded by a combination of logging, slash fires, and grazing resemble grassy or shrub balds, but most do not. The universal cattle grazing in grassy balds by early settlers has further obscured their original character and evidence of processes. Heath balds are more widely regarded as being created or maintained by fire. However, heavy organic accumulations in the soil suggest great age for some. Most show a very limited tendency to succeed to forest, suggesting that the dense shrub layer is highly competitive and that only infrequent fire would be needed to maintain them. As with the grassy balds, spruce-fir forests which burned in historical times do not usually develop vegetation identical to heath balds.