Tree ring cellulose δ¹⁸O of Fokienia hodginsii in northern Laos: A promising proxy to reconstruct ENSO?

A tree ring cellulose δ¹⁸O chronology of Fokienia hodginsii from 1951 to 2002 is established by four cores from four different trees to explore its potential for reconstructing climatic variations in northern Laos. This chronology is the first tree ring δ¹⁸O chronology from Laos as well as the first for this species. We compare variations of tree ring cellulose δ¹⁸O and ring width between cores. The results suggest that the δ¹⁸O time series are more strongly correlated between different trees than ring width time series are. In addition, correlation analysis shows a significantly negative correlation between tree ring cellulose δ¹⁸O and the May-October Palmer Drought Severity Index (PDSI), while the tree ring width indices have a poor correlation with PDSI. The spatial correlation analysis between tree ring cellulose δ¹⁸O and global sea surface temperature and the time series correlation analysis between tree ring cellulose δ¹⁸O and the Multivariate El Niño-Southern Oscillation (ENSO) Index (MEI) during the investigated period (1951-2002) reveal that ENSO has an important effect on tree ring cellulose δ¹⁸O in Laos. Our results indicate that the tree ring cellulose δ¹⁸O of Fokienia hodginsii is a promising proxy to reconstruct PDSI in Southeast Asian countries, such as Laos, and to discuss their teleconnections with global atmospheric circulations such as ENSO.