Analysis of the tree-ring width chronologies of Pinus koraiensis and Larix olgensis on Changbai Mountains,Northeast China

Tree-ring samples of Pinus koraiensis and Larix olgensis were studied along an altitudinal gradient on the northern slope of Changbai Mountains,Northeast China,and ring-width residual chronologies were developed for four sites at low and high elevations.Annual ring-width variability was different between elevation sites.For Pinus koraiensis,low elevation chronology had higher mean sensitivity(MS),standard deviation(SD) and signal-to-noise ratio(SNR),while high elevation chronology of Larix olgensis had higher mean sensitivity(MS),standard deviation(SD) and signal-to-noise ratio(SNR).Therefore,Pinus koraiensis growing at low elevation sites and Larix olgensis growing at high elevation sites had better climatic signals.Correlation analysis was used to study the relationships between tree-ring widths and mean monthly temperature and total monthly precipitation.The results showed that the growth of Pinus koraiensis at low elevations was affected by previous temperature and precipitation,and that at high elevations was only affected by temperature of current year.Temperature in the previous year played an important role in Larix olgensis' growth at low elevation sitea,while temperature and precipitation of current year made great contribution to Larix olgensis' growth at high elevation sites.With the increase of altitude precipitation increased,and more precipitation was related with low temperature.Consequently,tree growth was also affected by temperature with its indirect effect on the duration of growing season.Thus,the temperature was the most important factor influencing Larix olgensis,and showed that there was lag-effect of the growth response to climate force of low elevation.