Relationship Between Tree-ring Chronology Of Representative Species In Changbai Mountains And Climate Change.

Relationship between tree-ring chronology of representative species in Changbai Mountains and climate change.The purpose of this study is to reconstruct past climate change for the eastern part of northeast China based on a tree ring width network. Correlation analysis and superposed epoch analysis is used to determine the possible climatic signals in the tree ring STD chronology, RES chronology and regional signature years. The mean minimum temperature of current February to September of Changbai mountain area is reconstructed by multiple stepwise regression analysis based on the different standardized chronologies (double detrending and RCS-regional curve detrending).About 9 sampling sites, representing 5 endemic species, were collected. In this study, by analysis of tree-ring structure we try to investigate tree-ring sensitivity to climate in order to offer primary information of reconstructing past climate from the trees in this region. All the 5 species present distinct ring boundaries,few ABS(absent rings) and available for cross-dating. They all past the test by program COFECHA. Statistics for all the 8 tree-ring width residual chronologies also exhibit significant inter-correlation between series and high values of mean sensitivity. Under the background of global warming, there is a changing from positive response to negative response of the radial growth of spruce and larix to temperature at early 20th century. The positive relationship between the growth of lower altitude pine and temperature is relatively stable. This phenomenon suggests that the increasing temperature will have an negative effect on the growth of spruce and larix at the upper tree line in this Changbai mountain area. Also it must be considered when carrying out climate reconstructions in this area.Wavelet analysis was used to analyze the structure of period cycles of the reconstructed summer drought indices series. The abrupt change of average value in 1887 and the abrupt change of standard deviation in 1974 were found in the reconstructed series. The drought indices in May and June have a high correlation coefficient with the strength of polar eddy in North Hemisphere a few months before. A stronger polar eddv indicated a more arid climatic condition of China.