The sensitivity of tree growth to climate is conditioned by several variables, often intermingled, such as the origin of the forest (natural vs. artificial), tree age, tree size and tree-to-tree competition. The effect of these variables is usually inferred from average growth series obtained at the stand level, thus ignoring the differences at the individual tree level and their drivers. Our objective is to disentangle the effects of stand origin, age, size, competition and social status on the sensitivity of tree growth to climate, including the effects of extreme climatic events, such as droughts, on resistance and resilience, and also to show the advantages of using a tree-level approach. To this end, we compared four stands of with contrasting characteristics: young afforested, young of natural origin, old afforested and old of natural origin. We analyzed differences in growth sensitivity to climate at both stand and tree levels to compare both approaches. Our results show the great complexity of the relationships of the variables considered with the sensitivity of growth to climate. All these variables are important and with strong interactions between them, which makes their effects not unidirectional and strongly dependent on the site conditions. While the stand approach hides these interactions, the tree-level approach makes it possible to analyze them in detail. In general, the sensitivity of growth to climate increases with age, diameter, afforested origin, decreasing competition and higher social status; growth resistance increases with age, decreasing diameter, afforested origin, decreasing competition and higher social status; and growth resilience increases with age, diameter, natural origin, decreasing competition and higher social status. We show the usefulness of the analysis of data at individual tree level, which, combined with the joint analysis at stand level, allows us to obtain more accurate and detailed information.

中文翻译：

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从林分到树木水平的分析可以阐明年龄、大小、起源和竞争对自然和人工造林的欧洲赤松林树木生长对气候敏感性的影响


树木生长对气候的敏感性受到多个变量的影响，这些变量通常是混合在一起的，例如森林的起源（自然与人工）、树龄、树木大小和树与树之间的竞争。这些变量的影响通常是从林分水平获得的平均生长序列推断出来的，从而忽略了个体树木水平及其驱动因素的差异。我们的目标是理清林分起源、年龄、大小、竞争和社会地位对树木生长对气候敏感性的影响，包括干旱等极端气候事件对抵抗力和恢复力的影响，并展示使用树级方法的优点。为此，我们比较了四种具有对比特征的林分：年轻造林林、年轻自然来源林、老造林林和老自然来源林。我们分析了林分和树木水平上生长对气候敏感性的差异，以比较这两种方法。我们的结果表明，所考虑的变量与增长对气候的敏感性之间的关系非常复杂。所有这些变量都很重要，并且它们之间具有很强的相互作用，这使得它们的影响不是单向的并且强烈依赖于场地条件。虽然立场方法隐藏了这些相互作用，但树级方法使得详细分析它们成为可能。一般来说，生长对气候的敏感性随着年龄、直径、造林起源、竞争的减少和社会地位的提高而增加；生长阻力随着年龄、直径的减小、绿化起源、竞争的减少和社会地位的提高而增加；生长弹性随着年龄、直径、自然起源、竞争的减少和社会地位的提高而增加。 我们展示了单树级别数据分析的有用性，与林分级别的联合分析相结合，使我们能够获得更准确和详细的信息。