Collaborative Research: The Past, Present, and Future of Boreal Fire Feedbacks

北方森林环绕着地球，包含着地球上一些最大的碳储量。这些碳被锁在树木和土壤中，与大气隔绝。但随着气候变暖，火灾变得越来越普遍——尽管野火在北方地区并不罕见，但燃烧频率的增加已经超出了森林进化所能承受的范围，导致森林损失和永久冻土融化。我们不知道接下来会发生什么。如果森林不能从频繁的火灾中恢复过来，草和灌木可能会接管，进一步增加可燃性。或者它们可能会抑制未来的火灾活动。这个项目对北方地区的火灾进行了独特的研究，通过湖泊沉积物芯调查火灾的深层历史，在那里你可以看到数千年的火灾历史，通过实地调查来确定现在景观的恢复能力，并通过高性能的计算机模型来估计火灾在未来的表现。该项目跨越了许多时间尺度，将计算能力推向了极限，并将为这个生物群落和地球的未来提供预期。该项目将培训研究生、本科生和博士后学者，组织为期两天的科学交流研讨会，并完善用于向高中生教授碳-植被-火灾相互作用的火灾教学模型。该项目将采用综合动态方法，结合现有和新收集的沉积物数据，通过对短间隔火区的同期野外调查，探索北方寒带地区短间隔火灾的古代史。虽然已知现代火灾的频率超过了历史标准，但该项目将进一步确定当前的短间隔火灾是否正在创造新的结构。这些结构是未来火灾行为的基础，因此研究人员将把这些测量结果与现代的、基于物理的火灾行为流体动力学模型结合起来，该模型可以模拟封闭树冠和新型森林结构中的风。此外，该模型将扩展到包括土壤效应，这对北方地区至关重要。这是探索似乎正在出现的真正新颖物种组合和结构的火灾含义的唯一可行方法。总之，这项工作将探索与北方森林火灾行为相关的火灾可能性反馈和结构阈值，并就野火和能量平衡方面告知该地区如何应对气候变暖的预期。该项目将与非营利组织COMPASS合作，为更大的学术界的研究生和科学家组织一个为期两天的科学传播研讨会。他们还将与康科德联盟合作开发一个用于高中教学的模块工具，并与教师一起征求反馈。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。

Boreal forests circle the globe and contain some of the largest carbon stocks on the planet. Locked in the trees and soil, this carbon is sequestered from the atmosphere. But as the climate warms, fires are becoming more and more common – and while wildfire is not unusual in the boreal, the increasing frequency of burning is surpassing what the forests have evolved to tolerate, leading to forest loss and permafrost thaw. We do not know what comes next. It is possible that if the forest fails to recover from high frequency fires, grasses and shrubs may take over, further increasing flammability. Or they may dampen future fire activity. This project takes a unique look at fires in the boreal, by investigating the deep history of fire through lake sediment cores where you can see the history of fire over thousands of years, through fieldwork to determine how resilient the landscape is now, and through high-performance computer models to estimate how fires will behave in the future. The project spans many timescales and pushes computing powers to the limit and will inform expectations of the future for this biome and the planet. The project will train graduate students, undergraduate students, and postdoctoral scholars, organize a two-day science communication workshop, and refine a fire teaching model used to teach high schoolers about carbon-vegetation-fire interactions. Using an integrative and dynamic approach, this project will combine existing and newly collected sediment data to explore the paleohistory of short interval fires in the boreal with co-located fieldwork in short-interval fire areas. Although it is known that modern fire frequency is passing historical norms, this project will go further, to determine if current short interval fires are creating novel structures. Those structures are the basis for fire behavior in the future, so the researchers will then combine those measurements with modern, physics-based fluid dynamics modeling of fire behavior that can simulate wind in close canopies and in novel forest structures Further, this model will be extended to incorporate soil effects, critical in the boreal. This is the only available way to explore the fire implications of truly novel species assemblages and structures that seem to be emerging. Together, this work will explore fire likelihood feedbacks and structural thresholds associated with fire behavior in the boreal forest and inform expectations about how the region will respond, in terms of wildfire and energy balance, to climate warming. The project will work with the non-profit COMPASS to organize a two-day science communication workshop for graduate students and scientists in the larger academic community. They will also work with Concord Consortium to develop a module tool for teaching highschoolers, working with teachers to solicit feedback.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.