Analysis of fire suppression and increasing environmental variability on wildfire intensity

野火正在以几代人未曾见过的规模和强度燃烧，对流域、生态系统和人类社区具有潜在的破坏性影响。调查人员计划分析400年来的树木年轮火灾记录和1000年的热敏考古文物，以确定今天的火灾是否比历史上更热。经过一个多世纪的灭火，森林里充斥着灌木丛、枯死的燃料和过于茂密的树木。温暖的气温和严重的干旱使这些森林极易燃烧。由于这些混杂的因素，很难区分环境变化和灭火对野火的相对贡献。将最近在凉爽天气条件下发生的火灾与仅在灭火前燃料中燃烧的火灾进行比较，将使这些科学家能够将环境变化的影响与灭火的影响区分开来。这个项目训练美洲原住民学生，并使土地管理者能够更好地分配资源用于减轻野火的活动。经过一个世纪的灭火，许多森林以落叶、枯枝和树木的形式积累了燃料，幼树和灌木的密度也越来越高。更热的温度和普遍的干旱使这些积累的燃料更容易燃烧，并正在推动包括龙卷风在内的极端火灾行为。越来越大的“大火”影响了供水、生态系统，摧毁了成千上万的房屋。在这些背景下，很难分析环境变化和灭火的相对贡献，因为它们是同时运行的。然而，了解两者的相对重要性将有助于土地管理者和政策制定者分配资源以缓解这种情况。在这个项目中，研究人员使用了文物年代测定和木炭分析中的热敏考古代理的创新集成，以及树木年轮科学，以确定仅靠一个世纪的灭火积累的燃料是否足以推动火灾强度的增加，这在过去500-1000年里是前所未有的。他们调查灭火前经常烧毁的遗址(灭火前遗址)，以及在灭火一个世纪后在凉季条件下烧毁的遗址(灭火后遗址)。通过专注于冷季灭火后火灾，可以通过隔离灭火和燃料对火灾事件的温度和持续时间的影响来减少环境变化的影响。这项研究的结果有助于土地利用和火灾规划，使政策制定者能够更好地权衡森林集约化间伐和规定燃烧的机会成本与。环境缓解和家庭保护。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Wildfires are burning at scales and intensities not seen in generations with potentially devastating impacts on watersheds, ecosystems, and human communities. Investigators plan to analyze 400 years of tree-ring fire records and 1,000 years of heat sensitive archeological artifacts to determine if fires today are burning hotter than they have historically. After more than a century of fire suppression, forests are full of undergrowth, dead fuel, and overly dense stands of trees. Warmer temperatures and severe drought make these forests explosively combustible. It is difficult to disentangle the relative contributions of environmental change and of fire suppression to wildfires because of these confounding factors. Comparing recent fires under cool weather conditions versus those that only burned in pre-fire suppression fuels will enable these scientists to separate the influences of environmental change from those of fire suppression. This project trains Native American students and enables land managers to better allocate resources to activities that mitigate wildfires.As a result of a century of fire suppression, many forests have accumulated fuels in the form of leaf litter, dead and down branches and trees, and an increasing density of young trees and shrubs. Hotter temperatures and pervasive droughts make these accumulated fuels more combustible and are driving extreme fire behavior including fire tornados. Increasingly large "megafires" have impacted water supplies, ecosystems, and destroyed thousands of homes. It is difficult to parse the relative contributions of environmental change and fire suppression in these contexts because they are operating simultaneously. However, knowing the relative importance of each would aid land managers and policy makers to allocate resources to mitigate the situation. In this project researchers use an innovative integration of heat sensitive archaeological proxies in artifact dating and charcoal analysis, and tree-ring science to determine if fuels accumulated from a century of fire suppression alone are enough to drive increases in fire intensity that are unprecedented in last 500-1,000 years. They investigate sites that burned frequently prior to fire suppression to establish a baseline for historical conditions (pre-suppression sites) and sites that burned in cool-season conditions after a century of fire suppression (post-suppression sites). By focusing on cool-season post-suppression fires, the impact of environmental change can be reduced by isolating the impacts of fire suppression and fuels on the temperature and duration of fire events. The results of this study contribute to land-use and fire planning by allowing policymakers to better weigh the opportunity costs of intensive forest thinning and prescribed burning versus. environmental mitigation and home protection.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.