Climate change is increasingly favouring the occurrence of extreme weather events, affecting species distribution and tree growth. It has been proposed that mixed forests are more resistant to drought spells and heat waves than corresponding monocultures. We sampled tree cores in nine plots along a latitudinal gradient of the Italian Peninsula (Trentino, Molise and Calabria). The objective of the study was to identify radial growth responses in mixed-species and pure plots of European beech and silver fir to climate dynamics and extreme events. Pointer years, as well as correlation and response functions, were used to analyse the climate–growth relationships in mixed-species and pure plots. Climate–growth relationships showed differences between mixed-species and pure plots only at the regional level. In particular, Trentino differed from Molise and Calabria, when considering maximum temperatures. In Trentino, winter (for silver fir) and summer (for both species) temperatures had a less negative impact on the radial growth of trees, in comparison with Molise and Calabria. Nevertheless, correlations between the radial growth and drought indices, and the principal component analysis, showed that plots were relatively unresponsive to summer drought. These results can be important for the implementation of operational techniques that increase the adaptation of silver fir and European beech to climate change, as well as for assisted migration.

中文翻译：

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意大利半岛银杉和欧洲山毛榉混合物种和纯林林分的年际径向生长对气候变化和极端事件的敏感性

气候变化越来越有利于极端天气事件的发生，影响物种分布和树木生长。有人提出，混交林比相应的单一栽培更能抵抗干旱和热浪。我们沿着意大利半岛（特伦蒂诺、莫利塞和卡拉布里亚）的纬度梯度对九个地块的树芯进行了采样。该研究的目的是确定欧洲山毛榉和银杉的混合物种和纯地块对气候动态和极端事件的径向生长响应。指针年以及相关和响应函数被用于分析混合物种和纯地块中的气候-增长关系。气候-增长关系仅在区域层面显示混合物种和纯地块之间的差异。特别是，在考虑最高温度时，特伦蒂诺与莫利塞和卡拉布里亚不同。在特伦蒂诺，与莫利塞和卡拉布里亚相比，冬季（银杉）和夏季（两种物种）温度对树木径向生长的负面影响较小。然而，径向生长和干旱指数之间的相关性以及主成分分析表明，地块对夏季干旱的反应相对较弱。这些结果对于实施提高银杉和欧洲山毛榉对气候变化的适应能力的操作技术以及辅助迁移非常重要。与莫利塞和卡拉布里亚相比。然而，径向生长和干旱指数之间的相关性以及主成分分析表明，地块对夏季干旱的反应相对较弱。这些结果对于实施提高银杉和欧洲山毛榉对气候变化的适应能力的操作技术以及辅助迁移非常重要。与莫利塞和卡拉布里亚相比。然而，径向生长和干旱指数之间的相关性以及主成分分析表明，地块对夏季干旱的反应相对较弱。这些结果对于实施提高银杉和欧洲山毛榉对气候变化的适应能力的操作技术以及辅助迁移非常重要。