Reconstruction Of Eco-climate Indicators In Northern Mountain Of Jing-Ji Area Based On Tree Ring Data

The correlation analyses between chronologies of Pinus tabulaeformis,Picea jezoensis and Larix gmelini in Saihanba, the upstream of Luanhe River, Maojingba and Songshan and the climate factors were established to research into the different effects caused by temperature, precipitation and soil temperature.The experimental simulations of individual DBH growth process of different kind of trees were investigated using three kinds of theory growth function (Logistic, Richards and Gompertz),and the DBH was respectively obtained from the measured tree-width and the chronology in a period.The growth trend during the period showed:slow-fast-slow. The Richards theory growth function becomes the optimal equation of simulation in these areas.The growth trends generated by chronologies were consistent with the actual measured ones, they would become the substitute data in some research area.Different chronologies of different kinds of trees in different areas showed different relationship with the climate factors.The results of correlation coefficents between chronologies and different factors showed that chronologies had a obviously negative correlation with soil temperature, and mean temperature in main growing season (May-August), while positive correlation with the mean precipitation in the same period. It's meaningful in ecology to select last October to this September as the annual scale. The mixed chronologies by many kinds of trees were better indices than the chronologies just by the single ones to concretely and accurately react the climate changes.Establish the correlationship between four eco-climate indicators and chronologies, and then reconstruct the aridity index which is more comparable than the others from 1928-2009. The warm index, the cold index and the aridity index would get higher with the latitude getting lower, while the humidity index becomes lower.Compare with the disasters, the reconstructed curve displays significant cycles of 5-11 years.And because of the end of humid period in 2009, the next few years the local areas will be drought.