DEVELOPMENT AND CLIMATIC ANALYSIS OF A 456 YEAR TREE RING CHRONOLOGY FROM NORTHEAST OHIO, USA

Tree-ring series developed from old growth oak forests in Northeast Ohio are sensitive records of past moisture variability and have been used, together with a larger network of chronologies, to reconstruct drought histories on a continental scale. Here we describe the development and extension of ring-width records for Northeast Ohio from living oaks and from timbers in historical buildings. Over four hundred series from 10 old growth remnant forests and 16 historical sites are combined into a regional ring-width chronology that spans AD 1550-2005. These series are positively correlated with summer precipitation, summer Palmer Drought Severity Index and streamflow in the region. The five most-narrow rings (1699, 1748, 1810, 1839 and 1895) are inferred to have been extremely dry summers. Years 1699 and 1810 are linked to high latitude cooling associated with large-scale, volcanic events recognized in ice cores, but of uncertain origin.

Living trees show a general increase in ring-width over the last 150 years that is poorly understood, but may be related to the widespread forest disturbance and recovery after settlement in the early 1800s. Development of this record together with a more regional analysis and mapping of extreme years and long-period trends are ongoing. This work is leading to new insights into understanding drought and forest growth in the North American Midwest.