关键词: 树木年轮, 径向生长, 气候变化, 青藏高原东南缘

Abstract: To reveal the growth responses of different coniferous species to climatic factors in the southeastern Tibetan Plateau, we used dendrochronological techniques to sample tree-ring cores of the dominant species of alpine coniferous forest in Daofu County, western Sichuan Province, including Abies squamata, Picea likiangensis var. rubescens, Juniperus saltuaria, and Larix potaninii. We developed treering width chronologies of the four species and conducted growth-climate relationship analyses to understand the influence of climatic factors on tree radial growth. The results showed that tree growth responses to climatic factors differed among the four species. The radial growth of A. squamata and L. potaniniiwas significantly positively associated with mean minimum temperature (T_min) during most of the months in previous and current years, while the growth of P. likiangensis var. rubescens and J. saltuaria was not significantly correlated withT_min. Furthermore, relative humidity had strong limiting effect on the radial growth of P. likiangensis var. rubescens from previous October to current March, but had little influence on the growth of other three conifers. Since 1958, the relationship between the growth of A.squamataand the T_min in growing season (June to August) has remained stable, the relationship of radial growth of L. potaniniiandP. likiangensis var.rubescens with theT_min in growing season decreased first and then increased, while the association between J.saltuaria radial growth and growing season T_min has gradually decreased. Those results suggest that climate warming could benefit the development of A. squamata, L. potaninii and P. likiangensis var.rubescens and enhance tree radial growth, but weakly influence the radial growth of J. saltuaria, which may potentially affect stand structure and composition of alpine coniferous forest in this area.

Key words: tree-ring, radial tree growth, climate change, southeastern Tibetan Plateau.