Climate-growth relationships of Abies nephrolepis and its connection with large-scale climate change in Xiaoxing’an Mountains, northeastern China

Three tree-ring standard chronologies of Abies nephrolepis at different elevations in Fenglin National Nature Reserve from Xiaoxing’an Mountains of northeastern China were developed by using standard dendrochronological methods. Relationships between these three chronologies and local (mainly temperature and precipitation) and largescale climatic factors were analyzed. Results showed that radial growth of A. nephrolepis in this region was mainly limited by air temperature, while the effect of precipitation was relatively weak. Three A. nephrolepis chronologies were negatively correlated with minimum and mean temperatures in the current growth season (P0.01) and total precipitations in March (P0.05). Radial growth of A. nephrolepis in different elevations, however, responded differently to monthly mean temperatures and total precipitations. The effects of climatic factors (monthly temperature and precipitation) on tree growth in high elevations were significantly stronger than that in low elevations. Correlation analysis between three A. nephrolepis chronologies and the index of Pacific Decadal Oscillation (PDO) and Atlantic Multidecadal Oscillation (AMO) indicated that radial growth of A. nephrolepis could be connected with large-scale climate changes in Pacific and Atlantic. A greater effect of AMO on tree growth appeared in low elevation sites, while greater effect of PDO on tree growth was in two high elevation sites. The decline of valley spruce-fir forests in this region in recent years could be related to the phase changes of AMO and PDO, which changed the regime of temperature and precipitation in this region. Higher minimum temperatures in growing season caused by large-scale climate (AMO and PDO) changes decreased net photosynthesis and increased respirations of A. nephrolepis in this area. Thus, the physiological recession of tree growth will appear. In addition, higher temperature may result in the disappearance of patchy permafrosts in valleys, which will decrease water availability of soil in growing seasons. Therefore, spruce-fir forest declines in valleys in this region will occur.