Abstract: Based on the regional chronology established by the four ring-width standard chronologies of Sarcozygium xanthoxylon in the middle of Alashan Desert, we studied the response of Sarcozygium xanthoxylon radial growth to climate change and the wet/dry variation recorded by regional chronology. The results showed that the radial growth of Sarcozygium xanthoxylon was mainly affected by the pre-growing and growing season precipitation (October-December in previous year and April-July in current year). On the interdecadal scale, three dry periods were identified in the middle of Alashan Desert:the early 1920s to early 1930s, the early 1940s, the late 1970s to late 1980s; Four wet periods were the late 1900s to early 1920s, 1930s, the mid-1960s to mid-1970s, the late 1980s to the present. According to the results of wavelet analysis, the regional chronology in the middle of Alashan Desert had significant period cycles of 2-8 a, 11 a and 16-34 a, and the periodic oscillation occurred at the end of 1970s. These results could provide climate change information and decision-making basis for regional environmental evolution and desertification control.

Key words: Alashan Desert, shrub tree-rings, Sarcozygium xanthoxylon, climate response, wet/dry variation