RAPID: Collaborative Research: The 2016 Yellowstone Fires: early indicators of ecosystem transitions in a changing fire regime.

RAPID：合作研究：2016 年黄石火灾：火灾状况变化中生态系统转变的早期指标。

• 批准号: 1720620
• 负责人: Brian Harvey
• 金额: $ 5.7万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-04-01 至 2019-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1720620&HistoricalAwards=false
• 关键词: RAPID; Collaborative; Research; 2016; Yellowstone

Forests in the western US are facing warmer temperatures and larger, more severe wildfires than at any time in recorded history. Lodgepole pine forests of Yellowstone National Park (Wyoming) are well adapted to large, severe wildfires, which have burned at 100 to 300-yr intervals during the past 10,000 years. However, the interval between fires is shortening, making it likely that young forests will re-burn before fully recovering from previous fires. How forests will respond to more frequent fire and warmer, drier conditions is not known. Wildfires during summer 2016 burned young forests (less than 30 years old) that grew after the momentous 1988 Yellowstone Fires. These recent fires produced an unexpected opportunity to study the characteristics of short-interval fires and their effects on western pine forests. Sampling soon after severe fire is necessary because the time to find field evidence of burn severity is very short after the fire, and most tree seedlings establish during the first year after the fire. This RAPID award will measure burn severity, tree establishment and carbon storage in young forests that burned in 2016. Results will be immediately useful to regional forest managers, and mini-documentary videos will explain effects of increasing fire activity on western forests to a wide audience. Field data also will be used to improve computer models of forest growth and to assess burn-severity patterns across the US northern Rocky Mountains.Field studies in areas burned in the 1988 fires that burned again in 2106 will test three hypotheses. (1) Short-interval fires will reduce forest resilience because burns will be of high severity, and post-fire conifer regeneration and carbon storage will be substantially reduced. (2) Post-fire climate will amplify consequences of short fire-return intervals such that post-fire conifer establishment will be substantially reduced (or fail) in re-burns where conditions are warm and dry. (3) Regionally, the proportion of high-severity fire will be greater in short-interval than long-interval fires, but landscape patterns of high-severity fire will be similar. Burn severity, tree regeneration and carbon storage will be measured during summer 2017 in 0.25-ha plots following standard protocols. A seed addition experiment will be conducted to separate effects of seed supply from post-fire climate conditions on tree seedling establishment. Plot-based burn-severity data will be used to validate satellite-based burn-severity metrics and to map spatial patterns of burn severity in short-interval fires across the Northern Rockies. This study will help scientists and managers understand conditions likely to change forest ecosystems fundamentally in a future with more fire.

美国西部的森林正面临着有史以来最温暖的气温和规模更大、更严重的野火。黄石国家公园（怀俄明州）的黑松林非常适应大规模、严重的野火，在过去一万年里，野火每隔 100 至 300 年就会燃烧一次。然而，火灾之间的间隔正在缩短，使得年轻的森林有可能在从之前的火灾中完全恢复之前重新燃烧。森林将如何应对更频繁的火灾和更温暖、更干燥的条件尚不清楚。 2016 年夏季的野火烧毁了 1988 年黄石公园大火后生长的年轻森林（树龄不到 30 年）。最近的这些火灾为研究短时间火灾的特征及其对西部松林的影响提供了意想不到的机会。严重火灾后立即取样是必要的，因为在火灾发生后找到烧伤严重程度的现场证据的时间很短，而且大多数树苗在火灾发生后的第一年就长成。该 RAPID 奖项将衡量 2016 年燃烧的幼林的烧毁严重程度、树木生长和碳储存。结果将立即对区域森林管理者有用，迷你纪录片视频将向广大观众解释西部森林火灾活动增加的影响。现场数据还将用于改进森林生长的计算机模型，并评估美国落基山脉北部的烧毁严重程度模式。对 1988 年大火烧毁并于 2106 年再次烧毁的地区进行的现场研究将检验三个假设。 (1) 短时间火灾会降低森林的恢复力，因为烧伤会非常严重，火灾后针叶树的再生和碳储存将大幅减少。 (2) 火灾后气候将放大短火灾返回间隔的后果，使得在温暖和干燥的条件下重新燃烧时，火灾后针叶树的生长将大大减少（或失败）。 （3）从区域来看，短间隔火灾的比例会大于长间隔火灾，但高严重火灾的景观格局相似。烧伤严重程度、树木再生和碳储存将在 2017 年夏季按照标准协议在 0.25 公顷的土地上进行测量。将进行种子添加实验，以区分种子供应和火灾后气候条件对树苗生长的影响。基于地块的烧伤严重程度数据将用于验证基于卫星的烧伤严重程度指标，并绘制北落基山脉短间隔火灾烧伤严重程度的空间模式。这项研究将帮助科学家和管理者了解未来更多火灾可能从根本上改变森林生态系统的条件。