WIDTH AND OXYGEN ISOTOPE COMPOSITION OF TREE RINGS AS A PROXY FOR RECENT SOUTHERN INDIANA CLIMATE
Trees contain many proxies for past climate. Annual outward growth produces internal rings that are distinguishable from the previous year and contain important physical and chemical information. The rings provide many clues that help uncover the history of past conditions --- ring width, ring density, and chemical information including stable isotopes of oxygen, hydrogen, and carbon--- each of which are a consequence of climate parameters such as precipitation, humidity, and temperature.
In the spring of 2004, a collaborative effort between IU geologists and ISU geographers was initiated. Cores from 33 tree and 9 cross sections from 2 species (Quercas robur and Lirodendron tulipifera) were colleceted at the Lilly-Dickey Preserve. The site was chosen for its relatively abundant old growth for the region, enabling the record to be extended to the past 120 years. Paleoclimate analysis is underway using ring thickness and d18O of cellulose.