DENDROCHRONOLOGICAL ANALYSIS OF EASTERN HEMLOCK IN ERIE, PA

Eastern Hemlock is found throughout most of the northeastern United States and Canada and is most common on slopes and rocky areas. However, no known dendrochronological work has been performed on this species to examine its reaction to climatic and geologic events. Here, we report our initial results of an ongoing study aimed at building a master chronology using Eastern Hemlock for Erie, PA. The ultimate goal for this project is to determine the effects of temperature, precipitation, and climatic events on Eastern Hemlock in Erie County, PA. We have begun collecting cores from three Hemlock stands in Erie: Wintergreen Gorge, Asbury Woods, and Scott Park; 10 samples are being collected from each site. Once collected, cores are lightly sanded and individual tree rings are measured and counted under a binocular dissecting microscope. Initial results from samples collected from Wintergreen Gorge show average ring width is 1.65 mm. The largest recorded ring is 6 mm wide and the shortest is less than .5 mm wide. Maximum age of trees at Wintergreen gorge is approximately 135 years; we predict that ages of trees from other stands will provide similar maximum ages indicating that any developed master chronology using Eastern Hemlock in Erie may only be useful for approximately the last 100 years. Additional work will involve plotting tree ring data will be placed on a skeleton plot and in the Cofecha statistical program which will transfer the measurement data into a visual representation of the climatic and geologic effects on tree growth in graph form. Although we are ultimately only probing very shallow geologic time with our study, this work can provide a framework for future dendrochronological research on the Eastern Hemlock in the northeast United States and Canada, and may provide comparative data for similar analyses of other tree species in Erie County.