In subalpine forests of the western United States that historically experienced infrequent, high-severity fire, whether fire management can shape 21st-century fire regimes and forest dynamics to meet natural resource objectives is not known. Managed wildfire use (i.e., allowing lightning-ignited fires to burn when risk is low instead of suppressing them) is one approach for maintaining natural fire regimes and fostering mosaics of forest structure, stand age, and tree-species composition, while protecting people and property. However, little guidance exists for where and when this strategy may be effective with climate change. We simulated most of the contiguous forest in Grand Teton National Park, Wyoming, USA to ask: (1) how would subalpine fires and forest structure be different if fires had not been suppressed during the last three decades? And (2) what is the relative influence of climate change vs. fire management strategy on future fire and forests? We contrasted fire and forests from 1989 to 2098 under two fire management scenarios (managed wildfire use and fire suppression), two general circulation models (CNRM-CM5 and GFDL-ESM2M), and two representative concentration pathways (8.5 and 4.5). We found little difference between management scenarios in the number, size, or severity of fires during the last three decades. With 21st-century warming, fire activity increased rapidly, particularly after 2050, and followed nearly identical trajectories in both management scenarios. Area burned per year between 2018 and 2099 was 1,700% greater than in the last three decades (1989-2017). Large areas of forest were abruptly lost; only 65% of the original 40,178 ha of forest remained by 2098. However, forests stayed connected and fuels were abundant enough to support profound increases in burning through this century. Our results indicate that strategies emphasizing managed wildfire use, rather than suppression, will not alter climate-induced changes to fire and forests in subalpine landscapes of western North America. This suggests that managers may continue to have flexibility to strategically suppress subalpine fires without concern for long-term consequences, in distinct contrast with dry conifer forests of the Rocky Mountains and mixed conifer forest of California where maintaining low fuel loads is essential for sustaining frequent, low-severity surface fire regimes.

中文翻译：

---

荒地火灾管理能否改变美国怀俄明州大提顿国家公园 21 世纪的亚高山火灾和森林？

在美国西部的亚高山森林中，历史上曾发生过罕见的严重火灾，火灾管理能否塑造 21 世纪的火灾制度和森林动态以满足自然资源目标尚不清楚。管理野火使用（即在风险较低时允许闪电点燃的火灾而不是扑灭它们）是维持自然火灾状态和促进森林结构、林龄和树种组成马赛克的一种方法，同时保护人和财产。然而，几乎没有关于该策略在何时何地对气候变化有效的指导。我们模拟了美国怀俄明州大提顿国家公园的大部分连片森林，以询问：(1) 如果在过去的 30 年里没有扑灭火灾，亚高山火灾和森林结构会有什么不同？(2) 气候变化与火灾管理策略对未来火灾和森林的相对影响是什么？我们对比了 1989 年至 2098 年在两种火灾管理情景（管理野火使用和灭火）、两种一般环流模型（CNRM-CM5 和 GFDL-ESM2M）和两种代表性浓度路径（8.5 和 4.5）下的火灾和森林。我们发现在过去三年中，火灾的数量、规模或严重程度在管理方案之间几乎没有差异。随着 21 世纪的变暖，火灾活动迅速增加，特别是在 2050 年之后，并且在两种管理方案中遵循几乎相同的轨迹。2018 年至 2099 年间每年燃烧的面积为 1，比过去三个十年（1989-2017）高出 700%。大片森林突然消失；到 2098 年，原来 40,178 公顷的森林中只剩下 65%。然而，森林仍然相连，燃料充足，足以支持本世纪燃烧的大幅增长。我们的研究结果表明，强调管理野火使用而不是抑制野火的策略不会改变气候引起的北美西部亚高山地区火灾和森林的变化。这表明管理人员可以继续灵活地从战略上抑制亚高山火灾，而不用担心长期后果，这与落基山脉的干燥针叶林和加利福尼亚的混合针叶林形成鲜明对比，在这些林中保持低燃料负荷对于维持频繁、低严重性地表火灾制度。