VEGETATIVE STRUCTURE AND COMPOSITION OF SOUTHERN APPALACHIAN RIPARIANFORESTS

Vegetative characteristics of twelve Southern Appalachian riparian for ests were sampled as part of a larger study which examined functional attributes of riparian zones. Riparian forests were representative of the mixed mesophytic forest, eastern hemlock forest, and transitions b etween these types. Early- and mid-successional stages were generally dominated by an overstory of pioneering shade-intolerant species and h ad an even-aged structure. The diameter distribution of these relative ly young stands of mixed species was typically inverse J-shaped. Late- successional and old-growth stages were dominated by shade-tolerant or moderately tolerant overstory species and were uneven-aged. Diameter distribution in these older stands approximated a rotated sigmoid curv e. Rhododendron (Rhododendron maximum L.) was the dominant understory species and controlled understory and midstory composition. Characteri zation of riparian forests in different stages of succession will help understanding of vegetative processes and forms the basis of subseque nt ecological studies of riparian functional dynamics.