Forest Research Centre, School of Agriculture, University of Lisbon, Portugal; Department of Forest Engineering, Resources and Management, Oregon State University, Peavy Hall, Corvallis, OR, 97331, USA.
Department of Agricultural and Forest Engineering, Universitat de Lleida, Lleida, 25003, Spain.
J Environ Manage. 2022 Oct 15;320:115920. doi: 10.1016/j.jenvman.2022.115920. Epub 2022 Aug 4.
Despite growing interest in developing extensive fuel treatment programs to prevent catastrophic wildfires in the Mediterranean region, there is little information on the projected effectiveness of fuel treatments in terms of avoided exposure and risk. In Portugal, a fuel management plan aiming to prevent loss of lives, reduce large fires (>500 ha), and reduce annual burned area is under implementation, with particular emphasis on the nation-wide fuel break network (FBN). In this study, we evaluated the effectiveness of the planned FBN in terms of meeting fire management objectives, costs, and benefits. We first estimated the overall effectiveness of the FBN at intersecting modeled large fires (>500 ha) and at reducing exposure to protected areas and residential buildings using wildfire simulation modeling. Then, the fuel break burn-over percentage, i.e. the percentage of fires that are not contained at the FBN, was modeled as a function of pre-defined flame length thresholds for individual FBN segments. For the planned FBN, the results suggested a potential reduction of up to 13% in the annual burned area due to large fires (ca. 13,000 ha), of up to 8% in the annual number of residential buildings exposed (ca. 100 residential buildings), and up to 14% in the annual burned area in protected areas (ca. 2400 ha). The expected burn-over percentage was highly variable among the segments in response to estimated fire intensity, and an average decrease of 40% of the total benefits was estimated. The most important fuel breaks typically showed a higher percentage of fire burn-over, and hence reduction in effectiveness. We also showed that the current implementation of FBN follows a random sequence, suboptimal for all objectives. Our results suggest that additional landscape-scale fuel reduction strategies are required to meet short-term national wildfire management targets.
尽管人们越来越感兴趣地开发广泛的燃料处理计划，以防止地中海地区发生灾难性野火，但关于燃料处理在避免暴露和风险方面的预期效果的信息却很少。在葡萄牙，正在实施一项旨在防止生命损失、减少大型火灾（>500 公顷）和减少年燃烧面积的燃料管理计划，特别强调全国性的燃料阻隔网络（FBN）。在这项研究中，我们评估了计划中的 FBN 在实现火灾管理目标、成本和效益方面的有效性。我们首先使用野火模拟模型来估计 FBN 在拦截模型化的大型火灾（>500 公顷）和减少保护区和住宅建筑物暴露方面的总体有效性。然后，将燃料阻隔带的燃烧超过百分比（即没有在 FBN 内控制的火灾百分比）建模为单个 FBN 段的预定义火焰长度阈值的函数。对于计划中的 FBN，结果表明，由于大型火灾（约 13000 公顷），年燃烧面积可能减少 13%，年暴露的住宅建筑数量可能减少 8%（约 100 座住宅建筑），保护区的年燃烧面积可能减少 14%（约 2400 公顷）。预计在各个 FBN 段之间，由于估计的火灾强度，燃烧超过百分比具有高度的可变性，预计总收益会减少 40%。最重要的燃料阻隔带通常显示出更高的火灾燃烧超过百分比，因此有效性降低。我们还表明，当前 FBN 的实施遵循随机序列，对所有目标都不理想。我们的结果表明，需要采取其他景观尺度的燃料减少策略，以实现短期国家野火管理目标。
