Bark beetle outbreaks are a significant cause of high tree mortality rates, dramatically impacting the resilience of forests. Understanding the triggers and impacts of these outbreaks is critical for effective forest management strategies. In this context, we studied windfall and bark beetle outbreaks in the period 2015–2021 in the southern part of Kurilskiy Nature Reserve, North Pacific Ocean region. Massive bark beetle outbreaks on Kunashir Island were not previously studied. The dominant tree species are Yezo spruce () and Sakhalin fir (), which collectively form spruce-fir forests on Kunashir Island. Glehn spruce (), although less common on the island, forms pure spruce forests. Typically, spruce bark beetle () attacks Yezo and Glehn spruce, and fir bark beetle () attacks Sakhalin fir. Significant tree mortality was observed in the aftermath of a substantial bark beetle outbreak, induced by gale-force winds. The total disturbance area was 620.5 ha, which is about 4% of the study area, 72% of the windfall area, and 28% of the bark beetle-infested area.

中文翻译：

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北太平洋地区国后岛多种针叶林中两种树皮甲虫的侵染格局

树皮甲虫的爆发是树木死亡率高的一个重要原因，极大地影响了森林的恢复力。了解这些爆发的触发因素和影响对于有效的森林管理战略至关重要。在此背景下，我们研究了 2015 年至 2021 年期间北太平洋地区库里尔斯基自然保护区南部的意外收获和树皮甲虫爆发情况。此前并未对国后岛大规模树皮甲虫爆发进行过研究。优势树种为虾夷云杉 ( ) 和库页岛冷杉 ( ) ，共同形成国后岛上的云杉-冷杉林。格伦云杉（Glehn spruce）虽然在岛上不太常见，但却形成了纯净的云杉林。通常，云杉树皮甲虫 () 攻击叶佐云杉和格伦云杉，冷杉树皮甲虫 () 攻击库页岛冷杉。在强风引发的树皮甲虫大量爆发后，观察到树木大量死亡。总干扰面积为620.5公顷，约占研究面积的4%，意外收获面积的72%，树皮甲虫出没面积的28%。