With increased frequency and intensity of drought occurrence in the changing climate, the drought resilience of forest trees is of widespread interest. Particularly, it is not clear as to how the resilience differs between tree species and whether or not such resilience changes over time. Understanding tree resilience to drought requires observations not only from recent events but also from the historical past, information of which is usually hardly available. Here we defined historical drought based on isotope data and compared drought resilience in Juniperus tibetica and Abies spectabilis forest in the central Himalayas in five extreme droughts during the past two centuries. We found that juniper trees had a stronger resistance than fir trees in the three extreme droughts in the nineteenth century but this pattern reversed in the two drought events in the twentieth century. The length of response time to droughts and recovery time to pre-drought state were shorter in juniper trees than in fir trees. The proportion of declining trees showed a decreasing trend in fir trees but not in juniper trees. Our results indicate that the species-specific resilience might be related to the anisohydric (junipers) and isohydric (firs) strategies of stomatal regulation in response to droughts plants. The differences in species-specific drought resilience should be taken into account when developing forest management policies against the influence of extreme droughts in future.

随着气候变化中干旱发生的频率和强度的增加，森林树木的抗逆能力受到广泛关注。特别地，尚不清楚树种之间的弹性如何不同以及这种弹性是否随时间变化。要了解树木对干旱的抵抗力，不仅需要从最近的事件中获得观察结果，而且还需要从历史上获得观察结果，而这些信息通常很难获得。在这里，我们根据同位素数据定义了历史干旱，并比较了藏Jun和阔叶冷杉的干旱复原力在过去两个世纪中，喜马拉雅山中部的森林经历了五次极端干旱。我们发现，在19世纪的三场极端干旱中，杜松树的抵抗力强于枞树，但在20世纪的两次干旱事件中，这种格局发生了逆转。杜松树的干旱响应时间和恢复到干旱前状态的时间比杉树短。下降的树木比例在杉木树中呈下降趋势，而在杜松树中则没有下降趋势。我们的结果表明，物种特异性的抗逆性可能与响应干旱植物的气孔调节的异水（杜松）和异水（firs）策略有关。