Abstract Catastrophic floods and large debris flows are natural hazards common in mountain areas. They cause injuries and impact the radial growth of trees growing in the affected basins. Reconstructing how these catastrophic events impact trees by using dendrochronology improves our understanding of natural hazards. The 1996-Biescas (Central Spanish Pyrenees) flood was a catastrophic event causing the loss of many lives in a campsite located on an active alluvial fan. We investigated using tree rings how this catastrophic flood impacted planted trees (poplars, cedars) located in the campsite. Conspicuous scars in the stem were more abundant in cedar trees (75%) than in poplar (36%) trees. Scarred cedar trees formed traumatic resin ducts after the flood. In cedar tree perimeter influenced the size of the wound formed after the flood, but this was not observed in poplar. On average, 63% of trees showing scars formed them in the side of the stem (N-NW) where the impact of the flood was assumed to be strongest. We also detected sharp reductions of tree-ring width after the flood (–56% and –16% in poplar and cedar, respectively). However, this was not found when using basal area increment, which suggests there was an age effect on the post-flood growth changes. The two species mean chronologies were also more coupled after the flood in agreement with an increased responsiveness to climate, particularly a higher dependence of growth on June precipitation. To adequately reconstruct responses to flood and to assess the actual vulnerability of forests to debris flow impacts tree features such as species, age, growth rate and responsiveness to climate must be considered.

中文翻译：

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洪水过后的树木生长：基于树轮重建 1996-Biescas 灾难的影响

摘要 特大洪水和大型泥石流是山区常见的自然灾害。它们会造成伤害并影响受影响盆地中树木的径向生长。通过使用树木年代学重建这些灾难性事件如何影响树木，可以提高我们对自然灾害的理解。1996 年的比斯卡斯（西班牙比利牛斯中部）洪水是一场灾难性事件，在位于活跃冲积扇上的露营地造成许多人丧生。我们使用年轮调查了这场灾难性的洪水如何影响露营地内种植的树木（杨树、雪松）。雪松树 (75%) 的茎中明显的疤痕比杨树 (36%) 更丰富。洪水过后，伤痕累累的雪松树形成了创伤性的树脂管道。雪松树的周长影响了洪水后形成的伤口的大小，但这在杨树中没有观察到。平均而言，有 63% 的树木在树干的一侧（N-NW）形成了疤痕，在那里被认为洪水的影响最强。我们还检测到洪水后树木年轮宽度急剧减少（杨树和雪松分别为 –56% 和 –16%）。然而，在使用基础面积增量时没有发现这一点，这表明对洪水后的生长变化存在年龄影响。这两个物种的平均年表在洪水之后也更加耦合，这与对气候的响应增加一致，特别是生长对 6 月降水的依赖性更高。为了充分重建对洪水的响应并评估森林对泥石流影响的实际脆弱性，必须考虑树木的特征，如物种、年龄、生长速度和对气候的响应。