Abstract: In this study 160 tree cores were collected from Picea crassifolia in the upper reaches of the Shiyang River. After mounted, polished, cross dated and measured, the tree-ring width chronologies in the study area were developed. The monthly normalized difference vegetation index（NDVI）for the period from January 1982 to December 2006 was created using the GIMMS/NDVI data with the 8 km×8 km resolution from the NASA Goddard Space Flight Center. It was found that the annual NDVI curves were unimodal, the main growth season lasted from May to August, and the annual change of NDVI during the period of 1982-2006 was decreased in a fluctuation way. The relationships among tree-ring width index, NDVI and climatic data were analyzed. The results showed that both tree-ring width index and NDVI were strongly affected by precipitation during the period during non-growth period from September to next April, there was a significant positive correlation between tree-ring width index and precipitation during this period, but a significant negative correlation between NDVI and precipitation. The correlation between NDVI and tree-ring width index in plant growth season was poor, but there was a good negative correlation between them in non-growth season (r=-0.667, p<0.01).

Key words: Picea crassifolia, tree ring, NDVI, precipitation, Shiyang River