Comparing Climate Growth of Oak and Tulip Poplar Species in Bernheim Forest, Kentucky, USA Using Dendrochronological Methods

Jordan Sharp and Jacob Brown Department of Geographical and Environmental Sciences, University of Louisville Title: Comparing Climate Growth of Oak and Tulip Poplar Species in Bernheim Forest, Kentucky, USA using Dendrochronological Methods Abstract: With climate change, the state of Kentucky is expected to face increases in hydrological variability and extremes. To understand more about future projections, past climatic conditions can be analyzed with proxy-based data sources. Tree-rings provide annual to sub-annual resolution that can be used for proxy-based climate reconstructions. Kentucky, however, lacks tree-ring data and this leaves the state understudied from a high temporal and spatial resolution paleo perspective. In order to use tree-rings for climate reconstructions in Kentucky, climate sensitive sites and species must be identified and evaluated. The objective of the current study is to compare the climate-growth response of two populations of differing tree species: oak (QUSP) and tulip poplar (LITU) from Bernheim Arboretum and Research Forest near Louisville, KY. To compare these species, dendrochronological methods were used to measure annual tree growth and compiled these data points into two working chronologies. The chronologies show the annual average response from all the trees in the study site over time and the importance of the previous year’s climate on the current year’s climate on the growth of trees. The results of the analysis shows that both species showed sensitivity to climate until the 1970’s and then had a shift in temporal stability, indicating a change in their relationship to climate variables. The temporal instability and lack of climate sensitivity in recent decades shown in the climate growth analysis for Bernheim forest will have implications for further analysis when building a climate reconstruction for the state of Kentucky as reconstructions require temporal stability.