Evaluating Impacts of Climate Change on Deciduous Leaf Life Span in Tasmania and Indiana

C.N. KANE AND S.A.M. MCADAM

Purdue University, 915 Mitch Daniels Bvld, West Lafayette, IN 47907, USA

Climate change is shifting phenology in deciduous forests. Spring leaf-out is earlier than a century ago and will continue to advance, but little is known about the effect of climate change on senescence and abscission dates. To better understand this we measured leaf-out date, senescence rates, and leaf fall dates in six diverse, clonally-propagated deciduous tree species in Indiana, USA and Tasmania, Australia. We tracked leaf gas exchange rates, water potential, chlorophyll content and abscission zone formation over the growing season and determined xylem vulnerability to embolism in all trees to better understand if warmer temperatures and longer growing seasons might also lead to more carbon capture as the climate warms. These locations were selected due to a similar latitude but very different climate classifications, with Tasmania experiencing shorter, warmer winters with a minimal chance of frost compared to the long, cold winters of Indiana. We observed an earlier leaf-out in four tree species in the warmer Tasmania leading to significantly longer leaf life span and time frame to sequester carbon while two species showed no response to the warmer environment. Our results indicate that some species will be able to extend there growing season and capture more carbon annually.