The ecotone between a hardwood forest and a Rhododendron catawbiense heath bald was investigated at Craggy Gardens, North Carolina. Vegetation analysis indicates that an almost pure stand of beech trees (Fagus grandifolia) is encroaching on the heath community on the southeastern slope of Craggy Flats. The rate of invasion of beech is estimated to be 3 meters per year. At this rate, it can be predicted that beech forest will replace the heath bald in 50-75 years. This study contradicts the hypothesis that high elevation heath balds dominated by Rhododendron catawbiense represent stable climax communities.
Invasion may be facilitated by some process of interference between beech and rhododendron. At the contact zone of these two communities, many rhododendron shrubs directly below beech trees were dying and showed yellowing of leaves and reduced twig growth. Reproduction of beech is occurring by means of root sprouts. As beech roots move into the rhododendron community, rhododendron degenerates in the contact zone, opening the area to young developing beech sprouts.