|English Abstract: |
This study aims to assess the radial growth patterns and their responses to climate change of multiple tree species in the subtropical evergreen forest of Ailao Mountains, SW China. Four dominatetreespecies in the Ailao Mountains:Tetracentron sinense, Schimanoronhae, Hartiayunnanensisand Machilus gambleiwere selected.According to the basic principles of dendroclimatology, we sampled incrementcores for multiple tree species nearby Ailao Ecological station. Tree-ring width and d18O in cellulose were measured and correlated with meteorological data. We analyzedthe relationship between tree ring width of T.sinense, S. noronhaeand regionalclimatic variablesandexplored the possibility using tree ring cellulose δ18Oin H. yunnanensisfor cross-dating.The results showed that:
1. Amongsixsampledtree species in Ailao Mountains, tree ringboundaries of T.sinense, S. noronhae, H. yunnanensisand M. gambleiare distinct. Tree-ring width chronologies of T.sinense andS. noronhaewere developed successfully by cross-dating.
2. Comparing accumulated stem radial increments of the four tree species (T. sinense, S. noronhae, H. yunnanensisand M. gamblei), we found that growth rates of all four species werehigher than 2mm/a. The growth rateof H. yunnanensiswas significantly lower than the others.
3. Early growing season (February-March) was the key period for the radial growth of T. sinense. However, the climate condition during July-Septemberof previous yearplayed an important role on the radial growth of S. noronhae.
4. Oxygen isotope (δ18O)showed high inter-series correlations, thus was helpful for cross-dating. Relative humidity is a key factor influence tree ring cellulose δ18Oin this region. May was the key period affecting the δ18Oof T. sinense, while July-September was more important for δ18Oof H. yunnanensis.
5. This study showed that even in the warm andhumid subtropical forest, tree-ring width and wood cellulose δ18Oof tree species still preserve considerable climate information, which has high potential for reconstructing the past climate change.