Abstract The expected increase in drought severity and frequency as a result of anthropogenic climate change leads to concerns about the ability of native tree species to cope with these changes. To determine the susceptibility of Fagus sylvatica (European beech) and Quercus robur (pedunculate oak) – the two dominant deciduous tree species in Central Europe – to drought, we quantified the climate sensitivity and drought-response of radial growth for both species using an array of dendroecological methods. Tree-ring data were collected from a site east of Coburg, Bavaria which had shown pronounced stress-symptoms (early leaf coloration) during the record drought of 2018. Climate-growth relationships were used to establish the sensitivity of radial growth to multiple climatic variables. The impact of specific drought events on tree growth was quantified using tolerance indices. In addition, we employed a principal component gradient analysis (PCGA) and remote sensing data (MODIS Normalized Difference Vegetation Index (NDVI)) to delineate the species specific drought responses. Using these methods we were able to show a clear difference in drought susceptibility between beech and oak. Beech displayed a higher sensitivity to temperature and the standardized precipitation evapotranspiration index (SPEI) and showed lower resistance and resilience to drought events than oak. In particular, beech was unable to fully recover from the 2003 drought, after which it expressed a stark growth decline, i.e. drought legacies, which was not observed for oak. The PCGA revealed a clear differentiation in the grouping of drought responses between beech and oak, supporting the findings of the climate-growth analysis and the tolerance indices. Correlations of NDVI and ring-width indices (RWI) indicated that under normal climatic conditions NDVI variability is linked to the start of the growing season. This is in contrast to drought years, such as 2003, where summer NDVI mirrored the drought response of beech and oak. These results reveal beech to have both a higher sensitivity to summer temperature and SPEI and a higher susceptibility to drought events. Although, in the past high plasticity and adaptability to drought have been attributed to both beech and oak, our study assigns beech a higher risk than oak to suffer from anticipated increases in drought frequency and intensity as a consequence of climate change.

中文翻译：

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与橡木相比，山毛榉对干旱的敏感性更高

摘要 由于人为气候变化导致干旱严重程度和频率的预期增加，导致人们担心本地树种应对这些变化的能力。为了确定中欧两种主要落叶树种 Fagus sylvatica（欧洲山毛榉）和 Quercus robur（有花序橡树）对干旱的敏感性，我们使用阵列量化了这两个物种径向生长的气候敏感性和干旱响应树木生态学方法。年轮数据是从巴伐利亚州科堡以东的一个地点收集的，该地点在 2018 年创纪录的干旱期间表现出明显的压力症状（早期叶片着色）。气候-生长关系被用来确定径向生长对多个气候变量的敏感性. 使用耐受指数量化特定干旱事件对树木生长的影响。此外，我们采用主成分梯度分析 (PCGA) 和遥感数据 (MODIS 归一化差异植被指数 (NDVI)) 来描绘特定物种的干旱响应。使用这些方法，我们能够显示山毛榉和橡木之间的干旱敏感性存在明显差异。与橡木相比，山毛榉对温度和标准化降水蒸散指数 (SPEI) 表现出更高的敏感性，并且对干旱事件的抵抗力和恢复力较低。特别是，山毛榉无法从 2003 年的干旱中完全恢复，此后它表现出明显的生长下降，即干旱后遗症，这在橡木中没有观察到。PCGA 揭示了山毛榉和橡树之间的干旱反应分组的明显差异，支持气候增长分析和耐受指数的发现。NDVI 和环宽指数 (RWI) 的相关性表明，在正常气候条件下，NDVI 的变化与生长季节的开始有关。这与干旱年份形成对比，例如 2003 年，夏季 NDVI 反映了山毛榉和橡木的干旱响应。这些结果表明山毛榉对夏季温度和 SPEI 具有更高的敏感性，并且对干旱事件的敏感性更高。虽然，在过去，山毛榉和橡木都具有高可塑性和对干旱的适应性，