Forest development after succesive clearcuts in the Southern Appalachians

Abstract

A 16.1-ha watershed (Watershed 13, Coweeta Hydrologic Laboratory) was clearcut in 1939–1940 and again in 1962. Forest inventories were made in 1934, 1948, 1952, 1962, 1969, 1977 and 1984. Density, basal area, and size-class distribution of stems before the initial clearcut and during various stages of regrowth, were determined for each species. The even-aged, coppice forest of 1984 had a density and basal area of 2330 stems ha −1 and 20.83 m 2 ha −1, respectively, compared to 1934 values of 2632 stems ha −1 and 25.01 m 2 ha −1. Importance values, IV's [(relative density and relative basal area)/2], of mesic species, e.g., Betula lenta and Liriodendron tulipifera, have increased tremendously over the past fifty years due to their vital attributes (regeneration from sprouts and/or buried seeds, seed dispersal, fast growth, etc.) which have been favored by past disturbances, including clearcutting and chestnut blight. Importance values of Acer rubrum, Quercus coccinea and Q. prinus have increased moderately while IV's of Castanea dentata, C. pumila, Pinus rigida, Quercus alba and Q. rubra have decreased. The negative exponential function appropriately describes the size-class distribution of stems for all species combined for each census. Size-class distributions of individual species may (e.g., Acer rubrum) or may not (e.g., Liriodendron tulipifera) fit this function for any inventory, primarily due to differences in shade tolerance and growth rate among species. Present (1984) composition and structure (including vertical structure) are also presented according to three community types within this watershed: Cove Hardwoods, Mixed Oak, and Oak-Pine.