Collaborative Research: Wildfire and Mountain Pine Beetle Outbreaks in Subalpine Forests: Cross-Scale Interactions Under Varying Climate

从阿拉斯加西部到美国西南部，北美西部的针叶林中出现了大量的本土树皮甲虫（Dendroctonus spp.），据信这与气候变暖有关。在科罗拉多州，超过27万公顷的lodgepole松林最近受到山松甲虫（MPB） （D. ponderosae）的侵扰，这引起了公众对甲虫杀死后增加的火灾危险的广泛关注。本研究针对科罗拉多州北部亚高山森林野火、爆发和气候的相互作用及其潜在的跨尺度反馈的四个关键问题：1)季节、年度和多年代际时间尺度的气候变化如何影响MPB在复杂景观中的爆发和蔓延？2)在复杂的景观中，由先前的火灾干扰造成的景观异质性如何影响MPB爆发引起的后续干扰的风险和/或传播？3) MPB事前扰动造成的景观异质性如何影响复杂景观的燃料危害和野火风险？4)气候和景观之间的情境特定事件如何影响野火和MPB爆发的发生和蔓延？该项目将在不同的空间尺度和不同的气候条件下研究野火和树皮甲虫爆发之间可能的反馈。这项研究和相关的外联活动将增进对甲虫死亡对未来火灾风险影响的理解，这是资源管理者、防火社区和生活在树皮甲虫受影响地区的公众目前广泛关注的问题。

Large outbreaks of native bark beetles (Dendroctonus spp.) are occurring throughout coniferous forests of western North America, from western Alaska to the U.S. Southwest and are believed to be related to climatic warming. In Colorado more than 270,000 hectares of lodgepole pine forests have recently been infested by mountain pine beetle (MPB) (D. ponderosae), which has led to widespread public concern about increased fire hazard following beetle kill.This research addresses four key questions about interactions of wildfire, outbreaks and climate and their potential cross-scale feedbacks in subalpine forests in northern Colorado. 1) How does climatic variation at seasonal, annual, and multi-decadal time scales affect the initiation and spread of MPB outbreaks across complex landscapes? 2) How does the landscape heterogeneity created by prior disturbance by fire affect the risk and/or spread of subsequent disturbance by MPB outbreak across complex landscapes? 3) How does the landscape heterogeneity created by prior disturbance by MPB affect the fuel hazard and risk of wildfire across complex landscapes? 4) How do context-specific contingencies between climate and the landscape affect the initiation and spread of wildfire and MPB outbreaks?This project will examine possible feedbacks between wildfires and bark beetle outbreaks across different spatial scales and under varying climatic conditions. The research and associated outreach will improve understanding of the influence of beetle kill on future fire risk, which is of broad current interest to resource managers, the fire mitigation community and the public living in the bark-beetle affected areas.