Ecosystem response to the repeated interaction of disease and fire

该奖项的重点是对加州大苏尔地区火灾与森林疾病——橡树猝死病之间相互作用的长期研究。虽然火灾是加利福尼亚健康森林生态的重要组成部分，但橡树猝死病是一种最近引入的疾病，在过去的20年里，它已经杀死了加利福尼亚沿海地区数百万棵树。被疾病杀死的树木作为燃料，可能会增加火灾着火、蔓延和强度增加的风险。虽然火灾和疾病都造成广泛的树木死亡，但每种干扰类型都会对森林产生不同类型的影响和恢复。为此，本研究旨在确定多种和改变的干扰如何相互作用，以确定再生植物群落的组成，并塑造未来干扰的严重程度、频率和时间。野火的威胁在加利福尼亚和美国西部许多社区的政策决策中起着重要作用。随着越来越多的人居住在森林内或森林附近，扑灭野火的成本急剧增加。了解疾病和火灾如何相互作用影响森林，对于扑灭火灾、保护社区以及在灾难性火灾和疾病爆发后帮助森林恢复至关重要。大苏尔森林的病火相互作用将在一个8万公顷的地块网络上进行研究，该地块网络于2006年建立，用于研究橡树猝死。2008年和2016年，整个地块网络发生了大火，为大规模研究疾病与火灾的相互作用提供了机会。大苏尔样地网络的初步结果表明，这些森林生态系统正朝着疾病和火灾之间复杂相互作用的新干扰体制发展，影响了对任何一种干扰都有弹性的乔灌木物种。由于疾病的存在，野火严重程度的增加可能会增加不易受疾病影响的树种的死亡率，改变森林组合和生物地球化学循环，并最终为火灾和疾病的联合干扰如何在整个景观中重新出现创造条件。研究方法包括对长期田间样地的植被、病原菌和土壤养分进行监测，对病原菌进行实验室定量分析，建立统计模型。拟议的研究计划预计，由于大苏尔橡树猝死造成的树木死亡率将持续多年，从而影响燃料负荷和随后的自然火灾制度。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This award focuses on the long-term study of interactions between fire and a forest disease, Sudden Oak Death, in the Big Sur region of California. While fire is an important part of the ecology of healthy California forests, Sudden Oak Death is a recently introduced disease that has killed millions of trees in coastal California over the past 20 years. Disease-killed trees serve as fuel and may increase the risk for the ignition, spread, and increased intensity of wildfires. While fire and disease both cause extensive tree death, each disturbance type results in different types of impacts and recovery of forests. To that end, the proposed research seeks to determine how multiple, and altered, disturbances interact to determine the composition of the regenerating plant community and shape the severity, frequency, and timing of future disturbances. The threat of wildfire plays a major role in policy decisions in many communities throughout California and the western United States. The cost of fighting wildfires has increased dramatically as more people live in locations in and near forests. Understanding how disease and fire interact to impact forests is important in fighting fires, protecting communities, and in aiding the recovery of forests after catastrophic fire and disease outbreak.Disease-fire interactions in Big Sur forests will be examined across an 80,000 ha plot network that was established in 2006 to study Sudden Oak Death. Large fires burned across the plot network in 2008 and in 2016, providing an opportunity to study disease-fire interactions at a very large scale. Initial results from the Big Sur plot network indicate that these forest ecosystems are moving toward novel disturbance regimes with complex interactions between disease and fire, impacting tree and shrub species that are otherwise resilient to either disturbance. Increases in wildfire severity due to the presence of disease can increase mortality of tree species not susceptible to disease, alter forest assemblages and biogeochemical cycles, and ultimately, create the context for how the joint disturbances of fire and disease and will re-emerge across the landscape. The research approach includes monitoring the vegetation, pathogens, and soil nutrients of the long-term field plots, laboratory quantification of pathogens, as well as statistical modeling. The proposed research plan anticipates that the dramatic tree mortality due to Sudden Oak Death in Big Sur will continue for many years, thereby influencing fuel loading and subsequently natural fire regimes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.