RAPID: Collaborative Research: In-situ forest ecosystem response to wildfire

野火在美国西部森林中的频率和持续时间都在增加，因为火灾季节更长，燃料负荷更大，长期干旱和强烈的热浪。2020年，野火烧毁了美国俄勒冈州现有的研究森林，为研究火灾如何以及为什么杀死一些树木而不是其他树木创造了机会。这项研究将调查和跟踪遭受不同程度烧伤的森林树木的命运，确定树木死亡和存活的原因，并利用这些知识来确定野火对美国西部类似系统森林恢复的影响。了解树木如何在火灾和干旱中生存对于土地所有者和决策者制定管理计划以减轻森林压力和减少野火的风险和影响非常重要。该项目将为博士后研究人员提供培训，并有助于更广泛地了解火灾和森林结构如何影响碳和水循环。该研究将提供有关树木对不同火灾严重程度的敏感性、树木性状如何与烧伤严重程度相互作用以影响生存的关键知识，以及个体尺度上树木死亡率的变异性如何影响更大的生态系统过程，主要是净碳平衡。 这项研究将量化生态系统的响应和恢复在火灾严重程度的梯度，以回答这个重要的研究问题：野火对森林生态系统碳储量和通量，恢复力和死亡率在树，林分和生态系统水平的直接（数周）和短期（1年）的影响是什么？火灾后的数据将与现场现有的20年连续火灾前数据进行比较，包括涡度协方差、气象学、树冠下通量、自动土壤呼吸和成熟树木的液流。能够描述火灾后树木死亡和生态系统恢复的机制，对于利用基于过程的模型预测现在和未来更大规模的火灾影响非常重要。该奖项反映了NSF的法定使命，并被认为值得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来支持。

Wildfire is increasing in frequency and duration in Western US forests because of longer fire seasons, greater fuel load, prolonged drought, and intense heat waves. In 2020, wildfires burned existing research forests in Oregon, USA, creating the opportunity to study how and why fire kills some trees but not others. This research will investigate and track the fate of forest trees that suffered varying degrees of burn severity, determine reasons for tree death and survival, and use the knowledge to determine the impact of wildfire on forest recovery in similar systems across the western US. Knowing how trees survive fire and drought is important for land owners and policy makers in developing management plans for alleviating forest stress and for reducing the risk and impact of wildfire. This project will provide training for a postdoctoral researcher, and contribute to a broader understanding of how fire and forest structure affect carbon and water cycling.This research will provide critical knowledge about sensitivity of trees to varying fire severity, how traits of trees interacts with burn severity to impact survival, and how variability in tree mortality at the individual scale affects larger ecosystem processes, primarily net carbon balance. This research will quantify ecosystem response and recovery across a gradient of fire severity to answer this important research question: What are the immediate (weeks) and short-term (1 year) impacts of wildfire on forest ecosystem carbon stocks and fluxes, resilience, and mortality at tree, stand, and ecosystem levels? Post-fire data will be compared with the existing 20 years of continuous pre-fire data from the site, including eddy covariance, meteorology, subcanopy fluxes, automated soil respiration and sap flow on mature trees. Being able to characterize mechanisms for tree death and ecosystem recovery following fire is important for making predictions with process-based models of the impacts of fire at larger scales now and in the future.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.