GC33B-1287
Change of Tree-ring δ13C, δ18O and Water Use Efficiency of Loblolly Pine in Southeastern US in Response to Drought
Wednesday, 16 December 2015
Poster Hall (Moscone South)
Wen Lin1, Asko Noormets1, John King2, Ge Sun3, Steve G. McNulty2 and Jean-Christophe Domec4, (1)North Carolina State University Raleigh, Raleigh, NC, United States, (2)North Carolina State University at Raleigh, Department of Forestry and Environmental Resources, Raleigh, NC, United States, (3)USDA Forest Svc, Eastern Forest Environmental Threat Assessment Center, Raleigh, NC, United States, (4)USDA Forest Srvc-EFETAC, Raleigh, NC, United States
Abstract:
As a key parameter in carbon and water cycles of terrestrial ecosystems, water use efficiency is affected by isotopic signatures of the sources, climate, species- and site-specific characteristics such as mesophyll conductance(
Barbour et al., 2010) and stand structure (
Moreno-GutiÉRrez et al., 2012) . However, the magnitude of their effects and interactions are not well understood. Contributing to 36% of the sequestered forest carbon in the conterminous United States, the southern forests of USA are dominated by loblolly pine plantations. The objective of this study is to understand the response of loblolly pines to drought in terms of intrinsic water use efficiency and water source. We analyzed the δ13C and δ18O of α-cellulose extracted from latewood (summerwood) of tree rings produced in wet and dry years in 50 sites from southeastern USA and found that loblolly pines from different locations responded differently to droughts. Here we present our primary results in evaluating the effects of local climate variables, progeny of loblolly pines, and geographic locations on intrinsic water use efficiency.
