Dendrochronological investigation of disturbance history for a native American site in Northwestern Pennsylvania

Dendrochronological methods were used to identify the disturbance history of a Late Woodland Seneca Iroqouis settlement in northwestern Pennsylvania. The impacts of aboriginal disturbance on the landscape are widely speculative and few studies have attempted to characterize these disturbances. Increment cores taken from a 426 year old white oak forest remnant yielded information on the disturbance regime on this site during Native American (Late Woodland 1550-1700; Historic 1700-1800) and European (post 1800) settlement periods. Disturbances during the early and late native periods were more synchronous and of lower intensity (increase in growth rate) with a disturbance free interval (DFI) of 26.2 ± 4.0 years and 11.0 ± 0.7 years (mean ± SE), respectively. The shorter return interval during the later native period is attributed to the increased population pressure at this site due to immigration of natives in the face of European expansion from the eastern seaboard. The disturbance regime following European settlement is significantly longer with a DFI of 28.5 ± 2.8 years, representing the selective removal of merchantable timber for the sawmill located at the site. Although investigated, no climatic variables showed significant correlation with tree growth to explain these patterns. This study represents a rare opportunity to document the changes in disturbance regime between two drastically different cultures and land uses.