Age Structure and Successional Dynamics of a Presettlement-Origin Chestnut Oak Forest in the Pennsylvania Piedmont

Abstract

MIKAN, C. J., D. A. ORWIG AND M. D. ABRAMS (School of Forest Resources, Forest Resources Laboratory, Pennsylvania State University, University Park, PA 16802). Age structure and successional dynamics of a presettlement-origin chestnut oak forest in the Pennsylvania Piedmont. Bull. Torrey Bot. Club 121: 13-23. 1994.-This study investigated the community ecology of an old-growth Quercus prinus L. forest on a dry talus slope in southeastern Pennsylvania. Quercus prinus trees up to 367 years in age dominated the canopy layer. Acer rubrum L., Betula alleghaniensis Britton, Betula lenta L. and Nyssa sylvatica Marsh. occupied a small share of canopy space but dominated understory positions. Acer rubrum was the only canopy species present in significant numbers in the sapling layer. Presettlement forests of the region were dominated by Quercus velutina Lam., Quercus alba L., Castanea dentata (Marsh.) Borkh. and Carya spp. Following European settlement, frequent cutting and burning associated with the charcoal iron industry promoted oak coppice stands during the 19th century and prevented the development of a shade tolerant understory. Age determinations indicated that Q. prinus recruited continuously from 1625 until 1920. However, radial growth analysis indicated that peak recruitment of both the oak and mixed mesophytic tree species was associated with past disturbances. Cessation of frequent cutting, reduced occurrence of fire and the loss of C. dentata facilitated establishment of A. rubrum, B. lenta and B. alleghaniensis in the understory early this century. Results of this study indicate the potential for replacement of oak by more tolerant species on this and similar dry sites in the northern mid-Atlantic region which are traditionally considered to be physiographic or edaphic climaxes.