Wildfires often burn across boundaries affecting multiple jurisdictions, landowners and levels of government. Wildfire co-management across jurisdictions is expected to increase in complexity as wildfire severity, size, and frequency increase due to climate change, and growing populations bring more people into close proximity with wildfire. A systematic method to assess jurisdictional complexity for wildfire management is needed to effectively allocate resources and plan for future wildfire management conditions. Here, we developed an open-source framework of decision rules to count jurisdictions and landowners by coupling nearly 9,000 historic wildfire footprints that occurred across 43 U.S. states between 1999 and 2020 with geospatial jurisdictional data. We found that the number of annual wildfires greater than 500 acres has increased through time, with a proportional increase in the number of the highly complex (>7 jurisdictions; >3 levels of government) wildfires. Most wildfires burned 2–3 jurisdictions and 1 or 2 land ownerships, and the most common co-managed wildfires occurred on federal and private lands. On average, the western United States, specifically the Mediterranean California ecoregion, has more jurisdictionally complex wildfires, but the eastern United States, namely the Appalachian Mountains, has localized areas that experienced multiple wildfires with high and varied jurisdictional complexity. The prairies of Texas contained the largest extent of average low complexity wildfires. Of the 43 states that contained a wildfire, 41 had a census place that was burned or within 5 miles of a wildfire boundary, and overall, the annual number of census places near wildfires appears to be increasing through time. We demonstrate a framework that can be used to quantify jurisdictional complexity from observed wildfire boundaries and provide a baseline for discussing jurisdictional complexity at a national, regional, and sub-regional scale. This framework may also be adapted to other hazards or multi-jurisdictional phenomena that have geospatial boundary objects.

中文翻译：

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绘制野火管辖区的复杂性揭示了区域共同管理的机会

野火经常跨越边界燃烧，影响多个司法管辖区、土地所有者和各级政府。随着气候变化导致野火严重程度、规模和频率增加，以及人口增长使更多人近距离接触野火，跨司法管辖区的野火共同管理预计将变得更加复杂。需要一种系统方法来评估野火管理管辖区的复杂性，以有效分配资源并规划未来的野火管理条件。在这里，我们开发了一个决策规则的开源框架，通过将 1999 年至 2020 年间美国 43 个州发生的近 9,000 个历史野火足迹与地理空间司法管辖区数据相结合，来统计司法管辖区和土地所有者。我们发现，每年面积超过 500 英亩的野火数量随着时间的推移而增加，高度复杂（> 7 个管辖区；> 3 级政府）野火的数量也成比例增加。大多数野火烧毁了 2-3 个司法管辖区和 1 或 2 个土地所有权，最常见的共同管理野火发生在联邦和私人土地上。平均而言，美国西部，特别是地中海加州生态区，发生的野火地域复杂程度更高，但美国东部，即阿巴拉契亚山脉，局部地区经历了多次野火，地域复杂性高且多样。德克萨斯州的大草原是平均低复杂性野火范围最大的地区。在发生山火的 43 个州中，有 41 个州的人口普查点被烧毁或距离野火边界 5 英里以内，总体而言，每年靠近野火的人口普查点数量似乎随着时间的推移而增加。我们展示了一个框架，可用于根据观察到的野火边界来量化领土复杂性，并为在国家、区域和次区域范围内讨论领土复杂性提供基线。该框架还可以适用于具有地理空间边界对象的其他灾害或多管辖区现象。