Natural disturbances have significantly intensified across European forests, with bark beetle outbreaks being the most rapidly escalating disturbance type. Since 2018, the Czech Republic (Central Europe) has become a Europe's disturbance epicentre due to the unprecedented outbreak of spruce bark beetle Ips typographus in the forests dominated by Norway spruce Picea abies. Here we provide novel insights into the impacts and dynamics of this disturbance from 2016 to 2022. The investigation is based on annual forest change maps developed by the classification of optical and Synthetic Aperture Radar satellite imagery. We identified seven major outbreak foci across the country, where the outbreaks culminated between 2018 and 2021. Most of the outbreak waves exhibited a symmetric shape, characterized by a three-year build-up phase, a single culmination year, and the subsequent decline. The substantial proportion of spruce remaining in the outbreak areas after the culmination point implies that resource depletion is an improbable cause for the outbreak's retreat. In the year of retreat, the proportion of spruce in the forest ranged between 26% and 36% in most of the outbreak areas. The disturbance dynamics manifested a transition from the emergence of new tree mortality spots in the early outbreak phase to their short-range expansion, suggesting density-dependent changes in bark beetle dispersal during the studied period. The core disturbance zone, pinpointed in 2022, covered an area of 9,000 ​km2 and experienced a 38% loss in forest cover. Within this area, forest fragmentation increased significantly, leading to a greater forest patch complexity and reduced connectivity among the patches. The presented findings can serve as a glimpse into the future for other European regions, revealing the potential impacts of natural disturbances amplified by climate change.

中文翻译：

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中欧史无前例的树皮甲虫疫情的模式和影响：对未来的一瞥？


自然干扰在欧洲森林中显著加剧，树皮甲虫爆发是升级最快的干扰类型。自 2018 年以来，捷克共和国（中欧）已成为欧洲的干扰中心，因为在以挪威云杉 Picea abies 为主的森林中空前爆发了云杉树皮甲虫 Ips typographus。在这里，我们对 2016 年至 2022 年这种干扰的影响和动态提供了新的见解。该调查基于由光学和合成孔径雷达卫星图像分类开发的年度森林变化图。我们确定了全国七个主要的疫情重点，这些疫情在 2018 年至 2021 年期间达到顶峰。大多数爆发波呈对称形状，其特征是三年的积累阶段、单一的高潮年和随后的下降。在高潮点之后，疫情地区仍有相当一部分云杉残留，这意味着资源枯竭是疫情消退的不可能原因。在退缩的一年里，在大多数疫情地区，森林中云杉的比例在 26% 到 36% 之间。干扰动力学表现为从爆发早期新树木死亡点的出现到其短距离扩张的转变，表明研究期间树皮甲虫扩散的密度依赖性变化。2022 年确定的核心干扰区覆盖面积为 9,000 km2，森林覆盖率损失了 38%。在该区域内，森林破碎化显著增加，导致森林斑块复杂性增加，斑块之间的连通性降低。 所介绍的研究结果可以作为对其他欧洲地区未来的一瞥，揭示气候变化放大的自然干扰的潜在影响。