• Vulnerability to xylem cavitation is a strong predictor of drought-induced damage in forest communities. However, biotic features of the community itself can influence water availability at the individual tree-level, thereby modifying patterns of drought damage.
• Using an experimental forest in Tasmania, Australia, we determined the vulnerability to cavitation (leaf P₅₀) of four tree species and assessed the drought-induced canopy damage of 2944 6-yr-old trees after an extreme natural drought episode. We examined how individual damage was related to their size and the density and species identity of neighbouring trees.
• The two co-occurring dominant tree species, Eucalyptus delegatensis and Eucalyptus regnans, were the most vulnerable to drought-induced xylem cavitation and both species suffered significantly greater damage than neighbouring, subdominant species Pomaderris apetala and Acacia dealbata. While the two eucalypts had similar leaf P₅₀ values, E. delegatensis suffered significantly greater damage, which was strongly related to the density of neighbouring P. apetala. Damage in E. regnans was less impacted by neighbouring plants and smaller trees of both eucalypts sustained significantly more damage than larger trees.
• Our findings demonstrate that natural drought damage is influenced by individual plant physiology as well as the composition, physiology and density of the surrounding stand.

中文翻译：

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自然干旱期间的冠层损害取决于物种特性、生理学和林分组成

• 木质部空化的脆弱性是森林群落干旱引起的损害的一个强有力的预测因素。然而，群落本身的生物特征可以影响个体树木水平的水供应，从而改变干旱损害的模式。
• 我们使用澳大利亚塔斯马尼亚的一个实验森林，确定了四种树种对气蚀（叶 P _{50 ）的脆弱性，并评估了 2944 棵 6 年生的树木在经历了极端自然干旱事件后由干旱引起的树冠损害。}我们研究了个体损害与它们的大小以及邻近树木的密度和物种特性之间的关系。
• 两种同时出现的优势树种Eucalyptus delegatensis和Eucalyptus regnans最容易受到干旱引起的木质部空化的影响，并且这两个树种比邻近的次优势树种Pomaderris apetala和Acacia debata 遭受的损害要大得多。虽然两种桉树的叶片 P ₅₀值相似，但E. delegatensis遭受的损害明显更大，这与邻近P. apetala的密度密切相关。E. regnans的损害受邻近植物的影响较小，两种桉树的较小树木比较大的树木遭受的损害要大得多。
• 我们的研究结果表明，自然干旱损害受个体植物生理学以及周围林分的组成、生理学和密度的影响。