ECO-CBET: Collaborative Research: Effect of surface-fuel attributes and forest-thinning patterns on wildfire, carbon storage, and advancing forest restoration

2318717（Cobian）。近年来，严重的野火严重破坏了森林覆盖的山区流域，这些流域储存碳，供应西部各州的水，并提供许多共同利益。虽然周期性的低至中等严重程度的野火是美国西部森林的自然组成部分，但由于燃料负荷过多和气候变暖，该地区有太多的地区正在燃烧。因此，森林管理的一个关键目标往往是采用旨在减少严重火灾风险的做法。这些做法统称为森林恢复，包括间伐和移除或咀嚼耐火性较低的较小树木，同时留下较大的，间距更大的树木。一种常见的恢复方法是采用机械间伐，然后进行咀嚼，改变森林冠层结构和表面燃料负荷和特征。虽然它是已知的，通过咀嚼改变树木和其他植被的排列和密度会影响火灾行为，但缺乏对咀嚼燃料的属性如何影响随后的火灾严重性的定量了解。该项目的目标是开发燃料处理对火灾行为的影响的度量标准，跨越一系列的空间和时间尺度。该项目将有助于更好地了解管理决策产生的地表可燃物属性如何影响火灾行为和严重程度，从而影响森林生物量碳储存。虽然这些变化可以显着影响火灾行为，但它们对咀嚼类型和程度的敏感性尚不清楚。本研究的三个主要目标是：（1）确定在机械燃料处理后，异质和多尺度表面燃料负载和属性对这些燃料燃烧时的温度、火焰长度和火的蔓延的重要性;（2）在对比的微气象条件下，开发和评估给定这些不同燃料属性的森林野火严重性和蔓延的预测工具;以及（3）证明旨在减少高严重性野火发生和影响的不同燃料处理的碳储存和相关效益。该研究将使用实验室规模的燃烧实验，现场测量，包括控制燃烧在间伐和咀嚼站在混合针叶林，和荒地火灾和碳储存的建模。从实验，建模和现场规模的控制燃烧的评估结果将被用来确定在地面燃料的火灾严重性的关键驱动因素后变薄。该研究的主要贡献将是更好地了解管理决策产生的地表燃料属性如何影响火灾行为和严重程度，从而影响森林生物量碳储存。研究结果将改善火焰长度，火蔓延和碳平衡和存储在凋落物，矿质土壤和更深的风化层的建模。这项研究将使决策者和利益相关者与正在推进景观恢复的组织建立伙伴关系，为预测他们的投资如何影响野火严重程度提供急需的改进。该奖项反映了NSF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。

2318717 (Cobian). In recent years, high-severity wildfires have severely damaged forested mountain watersheds that store carbon, supply western-states’ water, and provide many co-benefits. While periodic low- to medium-severity wildfires are a natural part of western U.S. forests, too much of the area is burning at high severity owing to excessive fuel loads and a warming climate. Therefore, a critical goal of forest management is often the introduction of practices designed to reduce the risk of high severity fires. These practices, known collectively as forest restoration, involve thinning and removing or masticating the less-fire-resistant, smaller trees, while leaving larger, more widely spaced trees. A common restoration approach is applying mechanical thinning followed by mastication which changes the forest-canopy structure and surface-fuel loading and characteristics. While it is known that changing the arrangement and density of trees and other vegetation through mastication affects fire behavior, there is a lack a quantitative understanding of how attributes of masticated fuels affect subsequent fire severity. The goal of this project is to develop metrics of the impact of fuel treatments on fire behavior across a range of spatial and temporal scales. This project will contribute to improved understanding of how surface-fuel attributes, resulting from management decisions, influence fire behavior and severity and thus forest biomass carbon storage.Mechanical thinning followed by mastication changes the forest-canopy structure and surface-fuel loading and characteristics. While these changes can impact fire behavior significantly, their sensitivities to the type and degree of mastication are not well understood. The three main goals of the study are: (1) To establish the importance of heterogeneous and multiscale surface-fuel loadings and attributes, following mechanical fuel treatments, on the temperature, flame length, and spread of fire as these fuels burn; (2) To develop and assess predictive tools for wildfire severity and spread in the forest given these different fuel attributes, under contrasting micro-meteorological conditions; and (3) To demonstrate carbon-storage and related benefits from different fuel treatments designed to reduce the occurrence and impacts of high-severity wildfires. The study will use bench-scale combustion experiments, field measurements involving controlled burns in thinned and masticated stands in a mixed-conifer forest, and modeling of wildland fire and carbon storage. Results from experiments, modeling, and assessment of field-scale control burns will be used to identify key drivers of fire severity in ground fuels following thinning. Primary contributions of the study will be improved understanding of how surface-fuel attributes, resulting from management decisions, influence fire behavior and severity and thus forest biomass carbon storage. Results will improve modeling of flame length, fire spread and carbon balance and storage in the litter, mineral soil, and deeper regolith. This research will engage decision maker and stakeholder partnerships with organizations that are advancing landscape restoration, providing much-needed improvements in projection of how their investments may affect wildfire severity.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.