Zhang Peng, Jiao Liang, Wei Mengyuan, Wu Xuan, Du Dashi, Xue Ruhong
College of Geography and Environment Sciences, Northwest Normal University, Lanzhou, 730070, China.
Key Laboratory of Resource Environment and Sustainable Development of Oasis, Gansu Province, Lanzhou, 730070, China.
Int J Biometeorol. 2022 Dec;66(12):2449-2462. doi: 10.1007/s00484-022-02368-1. Epub 2022 Oct 6.
In the context of continued global climate change, the intensity and frequency of droughts have increased to varying degrees in many places. Due to the complexity of drought events, the mechanisms by which trees respond to drought are not well understood. In this study, we analyzed the growth trends of Qinghai spruce (Picea crassifolia) at different elevations in the western part of Qilian Mountains and the dynamic response to climate change. We also compared the differences in radial growth of trees at different elevations in response to drought events in the growing and non-growing seasons based on resistance (Rt), recovery (Rc), and resilience (Rs). The results showed that (1) trees at all three elevations were limited by drought stress and the lower the elevation the more sensitive the trees were to drought. (2) The response of middle- and low-elevation trees to the standardized precipitation evaporation index in June of that year was stable. (3) Growing season drought limits radial growth of trees more than non-growing season drought, and Rt is smaller and Rc is larger at low elevations. With increasing drought severity, trees at all three elevations exhibited a trend of decreasing Rt and Rs and increasing Rc. (4) There were significant differences in the growth trends of trees at the three elevations. Therefore, we should continuously pay attention to the dynamics of the forest ecosystem in the western part of Qilian Mountains and take improved measures to cope with the adverse effects of drought on Qinghai spruce.
在全球气候变化持续的背景下，许多地方干旱的强度和频率都有不同程度增加。由于干旱事件的复杂性，树木对干旱的响应机制尚未得到很好的理解。在本研究中，我们分析了祁连山西部不同海拔青海云杉（Picea crassifolia）的生长趋势以及对气候变化的动态响应。我们还基于抗性（Rt）、恢复力（Rc）和弹性（Rs），比较了不同海拔树木在生长季和非生长季对干旱事件的径向生长差异。结果表明：（1）三个海拔的树木均受到干旱胁迫限制，海拔越低树木对干旱越敏感。（2）中低海拔树木对当年6月标准化降水蒸发指数的响应较为稳定。（3）生长季干旱比非生长季干旱对树木径向生长的限制更大，低海拔地区Rt较小而Rc较大。随着干旱程度加剧，三个海拔的树木均呈现出Rt和Rs减小、Rc增大的趋势。（4）三个海拔树木的生长趋势存在显著差异。因此，我们应持续关注祁连山西部森林生态系统动态，并采取改进措施应对干旱对青海云杉的不利影响。
