A tree-ring width chronology developed from Pinus tabulaeformis tree-rings of Hasi Mountain was employed to analyze responses of tree-ring to different climatic metrics.Correlation analyses between tree-ring chronology and precipitation and temperature suggest that tree growth is both limited by precipitation and temperature,and moisture is the principal limiting factor of tree-ring width.To find a suitable moisture index to be reconstructed,three moisture indices considering precipitation and evaporation even water balance are chosen to be analyzed.The results suggest that the PDSI is an appropriate index as predictor of tree-ring width and can be used to reconstruct in this area.
[Objective] The aim was to analyze the correlation between tree-ring width of Picea crassifolia in the east of Qilian Mountains and the precipitation, temperature and the normalized difference vegetation index (NDVI). [Method] The correlation analysis and the regression analysis were used in this study. [Result] The tree-ring width was significantly correlated with the autumn precipitation and the spring average NDVI. The conversion equation between tree-ring width and spring NDVI (R2 = 48.5% , R2adj =46.2% , F =21.627, P <0.001) was developed and NDVI sequence was reconstructed during the period 1915 -2007. The drought in the 1920s was pronounced. Vegetation cover in the Qilian Mountains increased during the period 1922-1934, 1940-1957, 1965-1969, 1984-1988 and 1995-1997, but decreased during 1935 -1939, 1958 -1964, 1970 -1983, 1989 -1994 and 1998 -2005. [Conclusion] The reconstructed NDVI showed the drought evolution in the study area.
