Ager Alan A, Day Michelle A, McHugh Charles W, Short Karen, Gilbertson-Day Julie, Finney Mark A, Calkin David E
USDA Forest Service, Pacific Northwest Research Station, Western Wildland Environmental Threat Assessment Center, 75210 Coyote Road, Pendleton, OR 97801, USA.
Oregon State University, College of Forestry, Department of Forest Ecosystems and Society, 3200 SW Jefferson Way, Corvallis, OR 97331, USA.
J Environ Manage. 2014 Dec 1;145:54-70. doi: 10.1016/j.jenvman.2014.05.035. Epub 2014 Jul 2.
Substantial investments in fuel management activities on national forests in the western US are part of a national strategy to reduce human and ecological losses from catastrophic wildfire and create fire resilient landscapes. Prioritizing these investments within and among national forests remains a challenge, partly because a comprehensive assessment that establishes the current wildfire risk and exposure does not exist, making it difficult to identify national priorities and target specific areas for fuel management. To gain a broader understanding of wildfire exposure in the national forest system, we analyzed an array of simulated and empirical data on wildfire activity and fuel treatment investments on the 82 western US national forests. We first summarized recent fire data to examine variation among the Forests in ignition frequency and burned area in relation to investments in fuel reduction treatments. We then used simulation modeling to analyze fine-scale spatial variation in burn probability and intensity. We also estimated the probability of a mega-fire event on each of the Forests, and the transmission of fires ignited on national forests to the surrounding urban interface. The analysis showed a good correspondence between recent area burned and predictions from the simulation models. The modeling also illustrated the magnitude of the variation in both burn probability and intensity among and within Forests. Simulated burn probabilities in most instances were lower than historical, reflecting fire exclusion on many national forests. Simulated wildfire transmission from national forests to the urban interface was highly variable among the Forests. We discuss how the results of the study can be used to prioritize investments in hazardous fuel reduction within a comprehensive multi-scale risk management framework.
在美国西部的国有森林中，对燃料管理活动进行大量投资是一项国家战略的一部分，该战略旨在减少灾难性野火造成的人员和生态损失，并打造具有火灾恢复力的景观。在国有森林内部和之间对这些投资进行优先排序仍然是一项挑战，部分原因是目前不存在对当前野火风险和暴露情况的全面评估，这使得难以确定国家优先事项并针对特定区域进行燃料管理。为了更广泛地了解国有森林系统中的野火暴露情况，我们分析了一系列关于美国西部82个国有森林的野火活动和燃料处理投资的模拟数据和实证数据。我们首先总结了近期的火灾数据，以研究各森林在点火频率和烧毁面积方面的差异与燃料减少处理投资的关系。然后，我们使用模拟模型来分析燃烧概率和强度的精细尺度空间变化。我们还估计了每个森林发生特大火灾事件的概率，以及国有森林上引发的火灾向周边城市界面的蔓延情况。分析表明，近期烧毁面积与模拟模型的预测结果吻合良好。该模型还说明了各森林之间以及森林内部燃烧概率和强度变化的程度。在大多数情况下，模拟的燃烧概率低于历史水平，这反映了许多国有森林存在火灾排除现象。国有森林向城市界面的模拟野火蔓延在各森林之间差异很大。我们讨论了如何在全面的多尺度风险管理框架内，利用研究结果对危险燃料减少投资进行优先排序。
