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

这项研究项目将重现落基山脉北部部落土地上针叶混交林中过去数千年的历史火灾。类似的森林广泛分布在北美西部的内陆地区，但人们对它们的历史火灾动力学知之甚少，更不知道人类可能如何影响这些火灾。最近的大火以及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修复工作，旨在降低火灾风险和危险。与此同时，美国西部的野火扑灭成本已经上升到每年超过10亿美元，现在消耗了美国林务局预算的近一半。迫切需要更好地了解应用燃料处理的历史背景，以降低美国西部混合严重森林类型的火灾风险。在部落土地上，更好地了解森林管理的历史背景的必要性尤其引人注目，部落成员和森林管理者对保持历史连续性和将具有重要文化意义的做法纳入其管理战略具有强烈的兴趣。该项目将阐明古代和现代人类影响对火灾制度和针叶混交林的作用。项目成果将提供对影响当前森林林分特征的因素的机械性理解。该项目将有助于就古代和现代人类活动对温带森林的影响进行科学辩论。该项目将加强对面对不断变化的气候条件和土地利用的生态恢复能力的基本了解，并将促进对经历多种自然和人为压力的生态系统进行基于科学的管理。该项目将通过雇用十多名本科生和两名研究生，包括美洲原住民学生和部落学院的学生，帮助教育和培训新一代火灾和森林管理人员和研究人员。该项目还将帮助建立部落学院的研究能力。该项目将解决与过去和未来对火和森林生态系统的控制有关的下列问题：落基山脉北部针叶林的火势有多大变化？更干燥的混交林是否天生就比中生针叶林对最近火灾活动、虫害暴发和土地利用变化的增加更具弹性？旨在恢复针叶混交林中基线生态系统动态的处理是否代表了历史、自然和人为干扰过程？从过去的火-人-气候相互作用中吸取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支持未来森林管理的森林复原力？研究人员将结合从湖泊沉积物和树木年轮中重建的火灾和植被历史来回答这些问题，这些历史是从早期人类活动密集的配对地点和基本上与早期人类活动隔绝的配对地点网络中提取的。他们将把这些火灾的历史比作几个世纪以来气候的重建。该项目将阐明影响生态系统变化的自然和人为因素之间的相互作用，以便为支持森林复原力的恢复和管理战略提供信息，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.