• Key message Non-selective thinning of a hybrid aspen coppice stands via corridor or cross-corridor cutting impacts residual trees differently depending on their competitive status. Suppressed residual trees’ metabolic profile indicates increased stress level, especially after cross-corridor thinning. • Context Early thinning with regular corridor harvests is proposed for the management of post-harvest re-sprouted hybrid aspen ( Populus tremula L. × P. tremuloides Michx.) coppice stands. The selection of remaining trees is not size-based and their physiological acclimation to the post-thinning conditions is unknown. • Aims To analyse differences in secondary metabolite profile between thinning treatments and trees competitive status. • Methods We used an HPLC-qTOF mass spectrometer to analyse the leaf extracts of dominant and suppressed trees from stands with different thinning intensities: un-thinned control with basal area of 15.4 ± 1.52 m 2 ha −1 , corridor thinning with basal area of 8.5 ± 0.46 m 2 ha −1 and cross-corridor thinning with basal area of 3.9 ± 0.34 m 2 ha −1 . • Results Competitive status and thinning treatment both had significant effects on the contents of compounds. Higher exposure to irradiance increased the contents of flavonoids and hydroxycinnamates. Corridor thinning treatments doubled the foliar contents of secondary metabolites and lowered macronutrient contents in competitively suppressed residual trees. Dominant residual trees were not affected in this respect. • Conclusion Forest management practice and competitive status can significantly modify the metabolite profile in tree leaves. After corridor thinning of a young aspen coppice stand, the small-sized residual trees may initially respond with increased allocation to leaf chemical defence rather than to productivity.

中文翻译：

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杂种白杨叶片次生代谢物受密林竞争状态和早期变薄的影响

• 关键信息 通过廊道或跨廊道对混合白杨林进行非选择性间伐对剩余树木的影响取决于它们的竞争状况。被抑制的残余树木的代谢特征表明压力水平增加，尤其是在跨走廊变薄之后。• 背景 建议在收获后重新发芽的杂交白杨（Populus tremula L. × P. tremuloides Michx.）矮林丛中进行定期间伐的早期间伐。剩余树木的选择不是基于大小的，它们对间伐后条件的生理适应是未知的。• 目的 分析间伐处理和树木竞争状态之间次生代谢物特征的差异。• 方法 我们使用 HPLC-qTOF 质谱仪分析了来自不同间伐强度林分的优势树和抑制树的叶子提取物：未间伐对照，基面积为 15.4 ± 1.52 m 2 ha -1 ，廊道间伐，基面积为8.5 ± 0.46 m 2 ha -1 和跨走廊减薄，基础面积为 3.9 ± 0.34 m 2 ha -1 。• 结果 竞争状态和稀释处理都对化合物的含量有显着影响。较高的辐照度会增加类黄酮和羟基肉桂酸酯的含量。走廊间伐处理使次生代谢物的叶面含量增加了一倍，并降低了竞争性抑制的残留树木中的常量营养素含量。在这方面，优势残留树不受影响。• 结论 森林管理实践和竞争状况可以显着改变树叶中的代谢物谱。在对年轻的白杨矮林进行廊道间伐后，小型残留树木最初可能会增加分配给叶片化学防御而不是生产力。