Abstract Regional-scale mountain pine beetle (Dendroctonus ponderosae) outbreaks in the first decade of the 2000s affected millions of hectares of lodgepole pine (Pinus contorta) in western North American forests. In Colorado, 1.4 million ha exhibited high mortality. These events prompted questions about whether historical outbreaks reached the scale of this most recent event. We aimed to reconstruct past mortality events in lodgepole pine forests in the northern Colorado Front Range and to determine whether these were of similar extent to the 2000s outbreak. We identified logs of mountain pine beetle-killed trees based on visually identifiable signs of beetle infestation including lower bole breakage, egg galleries, exit holes, and the presence of blue stain. We collected cross-sections, developed tree ring chronologies and determined death dates through tree ring analysis. We detected five mortality events since the 1860s, including widely distributed mortality in the 1910s that was geographically as extensive as the 2000s outbreak in our study area. Trees killed were on average 232 years of age and 36 cm in diameter. In our study area, it takes about 200 years for a lodgepole pine to reach the size suitable for mountain pine beetle attack. We conclude that mountain pine beetle infestation signs remain useful for identifying mountain pine beetle-caused tree mortality for over a century and that well-distributed mountain pine beetle-caused mortality has occurred in the past in the northern Colorado Front Range. Future reconstructions of bark beetle-caused mortality may benefit from integrating the use of beetle symptomatology with growth releases. The inclusion of stand demography and fire history will present a holistic picture of how disturbance interactions create the mosaic of forest landscapes. Awareness of the disturbance histories in forests and the legacies of past events advances understanding of their ecology and will inform researchers and managers in developing management strategies to foster sustainable delivery of ecosystem services and maintain resiliency as climate change manifests.

中文翻译：

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重建科罗拉多前山脉黑松林中山松甲虫的历史爆发

摘要 在 2000 年代的前十年，区域规模的山松甲虫 (Dendroctonusponderosae) 暴发影响了北美西部森林中数百万公顷的黑松 (Pinus contorta)。在科罗拉多州，140 万公顷土地的死亡率很高。这些事件引发了关于历史爆发是否达到最近事件的规模的问题。我们旨在重建科罗拉多前线北部黑松林中过去的死亡事件，并确定这些事件的程度是否与 2000 年代的爆发相似。我们根据甲虫侵染的视觉可识别迹象（包括下部果核破损、卵廊、出口孔和蓝斑的存在）确定了被山松甲虫杀死的树木的原木。我们收集了横截面，制定了年轮年表并通过年轮分析确定了死亡日期。自 1860 年代以来，我们检测到五起死亡事件，包括 1910 年代广泛分布的死亡事件，其地理范围与我们研究区域的 2000 年代爆发一样广泛。被杀死的树木平均树龄为 232 年，直径为 36 厘米。在我们的研究区，一棵黑松大约需要 200 年的时间才能达到适合山松甲虫攻击的大小。我们得出的结论是，一个多世纪以来，山松甲虫侵染迹象对于确定山松甲虫引起的树木死亡率仍然有用，并且过去在科罗拉多前山脉北部发生了分布均匀的山松甲虫引起的死亡率。未来重建树皮甲虫引起的死亡率可能会受益于甲虫症状学的使用与生长释放的结合。包含林分人口统计学和火灾历史将呈现干扰相互作用如何创造森林景观马赛克的整体图景。了解森林中的干扰历史和过去事件的遗产可以促进对其生态的理解，并将为研究人员和管理人员制定管理策略提供信息，以促进生态系统服务的可持续提供并在气候变化显现时保持弹性。