Daxinganling New Forest Area Pinus Sylvestris Tree-ring ¦Ä <sup> 13 </ Sup> C Climate Significance

Tree-ring has been widely used in the filed of global climate change due to its advantages of accuracy for cross-dating, well continuity, high-resolution and high sensitivity to environmental changes. Tree-ring stable carbon isotope has been an importan technique in paleoclimate research because of its higher accuracy and sensitivity.Being the significant transition belt between East Asian monsoon area and west arid area, and the north of 400 mm isohyets of China, Daxing'anling Mountains are great important to the regional response of global climate change. We analyze the climatic significance of twoδ13C annual series (BZ1-1, BZ1-3) of Pinus Sylvestris var.mongolica in Xinlin Region of north Daxing'anling, to reveal the interrelation between tree-ring stable carbon isotope and climatic factors and the influence of climatic conditions to tree-ring stable carbon isotope change, and to reconstruct the climate history of this region, providing a reference for climate reconstruction using stable carbon isotope methods in other regions.According to the correlation analysis of tree-ring 813C of Pinus Sylvestris var.mongolica and climatic factors of Xinlin, we find that there has a positive correlation betweenδ13C and mean monthly temperature, mean monthly maximum temperature, mean monthly minimum temperature and sunshine duration(esp. in summer, late spring and early autumn), as well as a negative correlation between 813C and average relative humidity and average wind speed. And the complex correlation betweenδ13C and precipitation is worth paying attention to(δ13C has a negative correlation with summer and autumn precipitation while a positive correlation with winter snowfall before growing season). Multiple regression analysis shows that theδ13C annual change is mainly controled by temperature(mean monthly maximum temperature)and water factors(including precipitation and humidity), reflecting the growing character of Pinus Sylvestris var.mongolica and the climatic features of this important transition belt. And it possibly indicates that there has obvious differences between the two 813C series and their respective response to climate factors due to their wood ages and the different site habitats. Finally, we reconstruct the mean maximum temperature of May to September from 1900 to 2002 and the average relative humidity of June to August from 1955 to 2002, and it's proved to be credible and desirable by tests.