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

松毛虫Dendroctonus spp.发生在北美西部，从阿拉斯加西部到美国西南部的针叶林中，被认为与气候变暖有关。在科罗拉多州，超过27万公顷的松林最近受到山松甲虫的侵扰，这引起了公众对甲虫死亡后火灾危险增加的广泛关注。本研究针对科罗拉多州北部亚高山森林中野火、疫情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进行了研究。1)气候在季节、年度和数十年尺度上的变化如何影响MPB在复杂景观中的爆发和传播？2)先前火灾干扰造成的景观异质性如何影响随后MPB在复杂景观中爆发的干扰风险和/或传播？3)MPB先前干扰造成的景观异质性如何影响复杂景观中的燃料危险和野火风险？4)气候和景观之间的特定背景事件如何影响野火和MPB爆发的发起和传播？本项目将研究不同空间尺度和不同气候条件下野火和树皮甲虫爆发之间的可能反馈。这项研究和相关的推广将提高对杀死甲虫对未来火灾风险的影响的了解，这是资源管理者、火灾缓解社区和生活在受树皮甲虫影响地区的公众目前广泛感兴趣的问题。

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.