Frequent-fire forests of the western United States have undergone remarkable changes in structure, composition, and function due to historical exclusion of naturally occurring fire. Mechanized tree thinning to reduce forest density and fuel loads tends to be expensive and cannot be effectively implemented across all lands, and there is increasing interest in managing naturally ignited wildfires for meeting forest restoration objectives. To investigate general effectiveness of resource objective (RO) wildfires for restoring frequent-fire and associated forests of the western United States, we conducted a review of the related peer-reviewed literature. Formal analysis of ecological responses to RO fires is relatively recent, and 21 of the 37 papers (57%) we reviewed were published between the years 2010 and 2018. We found 17 studies that investigated RO fire outcomes in Sierra Nevada forests, while other ecoregions that were represented in the literature included Arizona–New Mexico Mountains, Middle Rockies–Blue Mountains, and the Colorado Plateau. Yosemite National Park was utilized in 14 of the studies we reviewed. We noted several ecoregions where frequent-fire forests occur, but for which published studies on RO fires are lacking. The main focus of research (14 studies) was related to RO fire effects on forest structure, and next in importance was research (12 studies) related to fire severity, extent, and type, with studies of understory vegetation responses and landscape-scale patterns or dynamics also prevalent. Research findings indicated that RO fires were effective for reducing tree density and fire behavior; however, densities often remained above known historical ranges of variation in several studies. Understory responses reported in the literature were mixed with respect to effects on abundance and species richness. Increases in invasive species abundance in areas of high burn severity were consistently reported. Research on landscape patterns indicated that RO fires can increase heterogeneity with respect to vegetation distribution. RO fires can be generally effective for restoration of frequent-fire forests, particularly on landscapes with long histories of fire use and in areas of moderate burn severity. More research is needed to test fire outcomes against specific restoration targets, and additional studies are needed concerning important ecological processes and functions.

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资源目标野火在美国西部森林中的恢复应用：知识回顾的现状

由于历史上对自然火灾的排斥，美国西部的频繁火灾森林在结构，组成和功能上发生了显着变化。机械化的树木稀疏以降低森林密度和燃料负荷往往很昂贵，并且无法在所有土地上有效实施，并且人们越来越关注管理自然点燃的野火以达到森林恢复目标。为了研究资源目标（RO）野火对恢复美国西部频繁发生的大火和相关森林的总体有效性，我们对相关的同行评审文献进行了回顾。对RO火灾的生态响应的形式化分析是相对较新的研究，我们审阅的37篇论文中有21篇（57％）发表于2010年至2018年之间。我们发现有17项研究调查了内华达山脉森林的RO火灾结果，而文献中代表的其他生态区域包括亚利桑那州-新墨西哥山，中洛基山脉-蓝山和科罗拉多高原。我们审查的14项研究均使用了优胜美地国家公园。我们注意到了几个经常发生森林大火的生态区域，但缺乏有关反渗透火的已发表研究。研究的重点（14个研究）与反渗透火对森林结构的影响有关，其次是与火灾严重性，程度和类型有关的研究（12个研究），研究对象是林下植被响应和景观尺度格局或动力学也很普遍。研究结果表明，RO火灾可有效降低树木密度和火灾行为。然而，在一些研究中，密度经常保持在已知的历史变化范围之上。关于丰度和物种丰富度的影响，文献中报道的林下反应是混杂的。持续报道烧伤严重程度高的地区入侵物种的数量增加。对景观格局的研究表明，反渗透火可以增加植被分布的异质性。反渗透火通常可以有效地恢复频繁燃烧的森林，特别是在使用历史悠久的火灾地区和严重烧伤的地区。需要针对特定​​的恢复目标进行更多测试以测试火灾结果，还需要针对重要的生态过程和功能进行更多研究。关于丰度和物种丰富度的影响，文献中报道的林下反应是混杂的。持续报道烧伤严重程度高的地区入侵物种的数量增加。对景观格局的研究表明，反渗透火可以增加植被分布的异质性。反渗透火通常可以有效地恢复频繁燃烧的森林，特别是在使用历史悠久的火灾地区和严重烧伤的地区。需要针对特定​​的恢复目标进行更多测试以测试火灾结果，还需要针对重要的生态过程和功能进行更多研究。关于丰度和物种丰富度的影响，文献中报道的林下反应是混杂的。持续报道烧伤严重程度高的地区入侵物种的数量增加。对景观格局的研究表明，反渗透火可以增加植被分布的异质性。反渗透火通常可以有效地恢复频繁燃烧的森林，特别是在使用历史悠久的火灾地区和严重烧伤的地区。需要针对特定​​的恢复目标进行更多测试以测试火灾结果，还需要针对重要的生态过程和功能进行更多研究。持续报道烧伤严重程度高的地区入侵物种的数量增加。对景观格局的研究表明，反渗透火可以增加植被分布的异质性。反渗透火通常可以有效地恢复频繁燃烧的森林，特别是在使用历史悠久的火灾地区和严重烧伤的地区。需要针对特定​​的恢复目标进行更多测试以测试火灾结果，还需要针对重要的生态过程和功能进行更多研究。持续报道烧伤严重程度高的地区入侵物种的数量增加。对景观格局的研究表明，反渗透火可以增加植被分布的异质性。反渗透火通常可以有效地恢复频繁燃烧的森林，特别是在使用历史悠久的火灾地区和严重烧伤的地区。需要针对特定​​的恢复目标进行更多测试以测试火灾结果，还需要针对重要的生态过程和功能进行更多研究。尤其是在长期使用火灾的环境以及严重烧伤严重的地区。需要针对特定​​的恢复目标进行更多测试以测试火灾结果，还需要针对重要的生态过程和功能进行更多研究。尤其是在长期使用火灾的风景以及严重烧伤严重的地区。需要针对特定​​的恢复目标进行更多测试以测试火灾结果，还需要针对重要的生态过程和功能进行更多研究。