Hotter droughts are becoming a major threat to forest growth in water-limited regions. Species interactions have long been acknowledged as an important component modulating ecosystem functions, including mediating their vulnerability to climate-related stresses. However, quantifying the impact of species interactions on forest growth in response to drought remains a challenge. Using the tree ring data of two species in two pure forests and two coniferous and broad-leaved mixed forests with different degrees of mingling in southern Siberia within the period of 1960–2017, we found that mixed forests with higher mingling have a higher ability to withstand the effect of extreme drought events, which is especially beneficial to the resistance and resilience of broad-leaved trees. Larch trees showed a remarkable consistency in their resistance and resilience to extreme drought events in both pure and mixed stands, suggesting their ability to promote the growth of neighboring white birch without reducing their own growth. The growth of white birch trees was enhanced in mixed forests and showed a significant trend of increasing resistance and resilience with increasing mingling. Our results provide further evidence of a decreasing duration of the legacy effect with increasing mingling for both coniferous and broad-leaved trees, which might explain the improved tolerance to drought of trees in mixed forests compared to those in pure forests in water-limited hemiboreal southern Siberia. Our study implies that changes in forest structure might help forests respond to hotter droughts in water-limited regions.

更热的干旱正在成为水资源有限地区森林生长的主要威胁。长期以来，物种相互作用一直被认为是调节生态系统功能的重要组成部分，包括调节它们对气候相关压力的脆弱性。然而，量化物种相互作用对应对干旱的森林生长的影响仍然是一个挑战。利用 1960-2017 年西伯利亚南部两个纯林和两个不同混交程度的针阔混交林中的两个树种的年轮数据，我们发现，混交程度越高的混交林对抵御极端干旱事件的影响，特别有利于阔叶树的抗逆性和恢复力。落叶松树在纯林和混合林中对极端干旱事件的抵抗力和复原力表现出显着的一致性，这表明它们能够在不降低自身生长的情况下促进邻近白桦的生长。白桦树的生长在混交林中得到增强，并且随着混交的增加呈现出明显的抗逆性和抗逆性增加的趋势。我们的研究结果进一步证明，随着针叶树和阔叶树的混合增加，遗留效应的持续时间会缩短，这可能解释了混交林中树木的耐旱性比水资源有限的半寒带南部纯林中的耐旱性有所提高。西伯利亚。我们的研究表明，森林结构的变化可能有助于森林应对水资源有限地区更热的干旱。