AGE STRUCTURE AND SUCCESSIONAL DYNAMICS OF A PRESETTLEMENT-ORIGIN CHESTNUT OAK FOREST IN THE PENNSYLVANIA PIEDMONT

This study investigated the community ecology of an old-growth Quercus prinus L. forest on a dry talus slope in southeastern Pennsylvania. Q uercus prinus trees up to 367 years in age dominated the canopy layer. Acer rubrum L., Betula alleghaniensis Britton, Betula lenta L. and Ny ssa sylvatica Marsh. occupied a small share of canopy space but domina ted understory positions. Acer rubrum was the only canopy species pres ent 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 determin ations 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. rub rum, B. lenta and B. alleghaniensis in the understory early this centu ry. Results of this study indicate the potential for replacement of oa k by more tolerant species on this and similar dry sites in the northe rn mid-Atlantic region which are traditionally considered to be physio graphic or edaphic climaxes.