Forest composition, structure, and disturbance history of the Alan Seeger Natural Area, Huntington County, Pennsylvania

Abstract

on wet stream bottoms, Tsuga-Pinus on wet to mesic stream terraces, mixed mesophytic species within a mesic upland cove, and mixed Quercus on mesic to dry upland slopes. Based on tree recruitment and radial growth patterns, low-intensity exogenous disturbances occurred every 30-60 yr during the presettlement era. Extensive logging during the mid- I 840s was evident throughout the area, and, along with subsequent disturbances, had a profound effect on current forest composition and structure. Tree species responded differently to major anthropogenic disturbance, in terms of growth rate and canopy positioning. In general, Pinus strobus L., Liriodendron tulipifera L. and Quercus responded favorably to disturbance, whereas Acer, Betula alleghaniensis Britton and Tsuga canadensis (L.) Carr recovered more slowly. Current forest age structures reflect different disturbance patterns and rates of recovery, and were categorized as either even-aged, uneven-aged consisting of 2 distinct even-aged cohorts, or uneven-aged with extended recruitment (multiple small-scale disturbances). Successional patterns currently exhibited in all forests may be drastically altered in the future from overbrowsing by whitetailed deer (Odocoileus virginianus) and/or intense shrub competition on tree regeneration.