Multi-Scale Reconstructions of Human-Climate-Fire Interactions in Mixed-Conifer Forests of the Northern Rockies

这个研究项目将在落基山脉北部部落土地上的混合针叶林中重建过去几千年来的历史火灾。类似的森林在北美西部内陆广泛存在，但人们对它们的历史火灾动态知之甚少，对人类如何影响这些火灾的了解就更少了。最近的大型火灾和对未来几十年火灾活动增加的预测，促使美国的土地管理机构启动了广泛的恢复工作，旨在减少火灾风险和危害。与此同时，美国西部的野火扑灭费用每年已经上升到10亿美元以上，现在消耗了美国林务局预算的近一半。我们迫切需要更好地了解在美国西部混合严重程度的森林类型中应用燃料处理以降低火灾风险的历史背景。在部落土地上，更好地了解森林管理的历史背景尤为迫切，因为部落成员和森林管理者对保护历史连续性和将文化上重要的实践纳入其管理策略有着强烈的兴趣。该项目将阐明古代和近代人类对火情和混合针叶林的影响。项目结果将提供形成当前林分特征的因素的机制理解。该项目将有助于就古代和近代人类活动对温带森林的影响进行科学辩论。该项目将增强对气候条件和土地利用变化下生态恢复力的基本认识，并将促进对遭受多种自然和人为压力的生态系统进行科学管理的发展。该项目将通过雇用十多名本科生和两名研究生，包括美洲土著学生和部落学院的学生，帮助教育和培训新一代的火灾和森林管理人员和研究人员。该项目还将帮助建立一所部落学院的研究能力。该项目将解决以下与过去和未来对火灾和森林生态系统的控制有关的问题：北落基山脉混合针叶林的火灾状况有多可变？干燥的混合针叶林是否天生就比混交针叶林更能适应最近火灾活动、昆虫爆发和土地利用变化的增加？旨在恢复具有历史自然和人为干扰过程代表性的混合针叶林的基线生态系统动态的处理措施？过去火-人-气候相互作用的经验教训如何帮助土地管理者以最终降低灭火成本的方式，在未来的森林管理中支持森林恢复力？研究人员将通过结合从早期人类活动密集的成对地点和基本上与早期人类活动隔离的成对地点采集的湖泊沉积物和树木年轮采样重建的火灾和植被历史来回答这些问题。他们将把这些火灾历史与几个世纪以来的气候重建进行比较。该项目将澄清影响生态系统变化的自然因素和人为因素之间的相互作用，以便为恢复和管理战略提供信息，从而支持森林恢复能力，最终降低野火风险和灾害的成本。

This research project will reconstruct historical fires over the past several thousand years in mixed-conifer forests on tribal lands in the northern Rockies. Similar forests are widespread in the interior of western North America, but little is known about their historical fire dynamics, and even less is known about how humans may have influenced those fires. Recent large fires and projections of increased fire activity in the decades ahead have prompted land-management agencies in the U.S. to initiate widespread restoration efforts aimed at reducing fire risk and hazard. At the same time, wildfire suppression costs in the western U.S. have risen to more than $1 billion annually and now consume nearly one-half of the U.S. Forest Service budget. There is a critical need to better understand the historical context for applying fuel treatments intended to reduce fire risk in mixed-severity forest types across the western U.S. The need to better understand the historical context for forest management is particularly compelling on tribal lands, where tribal members and forest managers have a strong interest in preserving historical continuity and incorporating culturally important practices into their management strategies. The project will clarify the role of ancient and recent human influence on fire regimes and mixed-conifer forests. Project results will provide a mechanistic understanding of factors shaping current forest stand characteristics. The project will contribute to scientific debates concerning the influence of both ancient and recent human activities on temperate forests. The project will enhance basic understanding of ecological resilience in the face of changing climatic conditions and land use, and it will facilitate the development of science-based management for ecosystems experiencing multiple natural and human-caused stressors. This project will help educate and train a new generation of fire and forest managers and researchers by employing more than ten undergraduates and two graduate students, including Native American students and students from tribal colleges. The project also will help build research capacity at a tribal college.This project will address the following questions related to past and future controls on fire and forest ecosystems: How variable were fire regimes in mixed-conifer forests of the northern Rockies? Are drier mixed-conifer forests inherently more resilient than mesic ones to recent increases in fire activity, insect outbreaks, and land-use change? Are treatments aimed at restoring baseline ecosystem dynamics in mixed-conifer forests representative of historical natural and human disturbance processes? How can lessons from past fire-human-climate interactions help land managers support forest resilience with future forest management in ways that ultimately reduce fire suppression costs? The investigators will answer these questions by combining fire and vegetation histories reconstructed from lake sediments and tree rings sampled from a network of paired sites in which early human activity was intensive versus paired sites that were largely isolated from early human activity. They will compare these histories of fire to multi-century reconstructions of climate. This project will clarify interactions between natural and human factors that influence ecosystem change in order to inform restoration and management strategies that support forest resiliency in ways that ultimately reduce the cost of wildfire risk and hazard.