Synchrony patterns of radial growth of Qinghai spruce (Picea crassifolia) across elevational gradients in the eastern Qilian Mountains

Abstract

Investigating the growth synchrony of a tree species across spatiotemporal scales could enhances the understanding of species' climatic responses, which is particularly critical for addressing future ecological risks under climate change. However, studies on the growth synchrony of Picea crassifolia across elevation remain largely unclear in the Qilian Mountains. The tree cores of 592 P. crassifolia were collected from nine forest sites in the eastern Qilian Mountains to investigate the tree growth synchrony and its climatic drivers. The growth synchrony of P. crassifolia was the highest at 3100–3200 m during 1975–2005 but showed a significant decline with time. Although it was lower, the growth synchrony of P. crassifolia remained stable at 2712–2800 m and 2900–2960 m. At high elevations, current January precipitation, temperature in preceding August, and precipitation and temperature variability in preceding July explained 89 % of the changes in growth synchrony. At low elevations, variability of drought in October and the temperature during spring-summer accounted for 42 % of the synchrony changes. At middle elevations, only the variability of summer temperature and the drought in July explained 17 % of the synchrony changes. The high explanatory power of climatic factors for the synchrony changes at high and low elevations indicates that forest management strategies should pay increased attention to the ecological responses in these regions under changing climatic conditions.