Doctoral Dissertation Research: Fire Regimes, Forest Succession, and the Varying Effects of Fire Suppression Across the Central Range of Whitebark Pine

白皮松是喀斯喀特山脉和落基山脉高地的象征，是支持复杂野生动物网络的关键物种，也是整个美国西部高海拔生态系统的重要组成部分。不幸的是，在过去的世纪，由于自然和人为原因，该物种在其分布范围内经历了急剧下降。灭火通常是牵连作为一个促成因素，其下降，但广泛的差距存在于过去的火灾制度和结构的白皮松森林的知识在大部分的物种范围。本博士论文研究将使用多尺度方法来阐明过去的火灾活动与白皮松森林的组成和结构之间的复杂相互作用，在不同的生物物理环境和大尺度气候变化的背景下。具体而言，以下研究问题的答案将寻求：什么是历史范围内的变化在整个中央分布的物种的白皮松森林的火灾制度？这些森林中火灾活动时空变化的驱动机制是什么？灭火如何影响以不同干扰制度和生物物理环境为特征的森林结构？本研究的研究地点将设在从蒙大拿州西南部到俄勒冈州喀斯喀特山脉的几个国家森林和荒野地区的三到四个流域内。在每个站点，森林结构和组成数据将通过林分调查和树木生态学采样获得，火灾历史数据将通过收集部分横截面从火灾后留下疤痕的树木，障碍物，并在情节和周围地区的材料。这些数据将被用来描述每个站点的立场和干扰的历史，探索潜在的过程，导致这些模式，并比较和对比这些模式在时间和空间。这项研究将填补现有火灾历史遗址网络中的物理空白，以及对混合严重程度火灾制度、它们所维持的生态系统以及它们所经历的最近生态变化的理解中的理论空白。这项研究将提供一个框架，以促进管理计划的发展，以保护这一下降的物种和它所支持的生态系统。收集的所有数据将在可公开访问的国际树轮数据库和国际多代理古火数据库中存档，该项目产生的所有出版物和报告的副本将分发给每个参与的国家森林办事处和白皮松生态系统基金会。该项目将支持多个本科生在现场和实验室设置，加强他们未来的就业机会。 展示样本将作为解释对象提供给所有参与的国家森林办公室，以帮助教育公众关于火在白皮松生态系统中的作用。一名中学科学教师也将协助该项目的各个方面，从而积累树木生态学研究和白皮松生态学方面的经验，他将与学生分享。

Whitebark pine is a symbol of the high country of the Cascades and Rocky Mountains, a keystone species that supports an intricate network of wildlife, and a vital component of high-elevation ecosystems throughout the western United States. Unfortunately, this species has experienced dramatic declines throughout its range over the past century due to both natural and anthropogenic causes. Fire suppression is commonly implicated as a contributing factor to its decline, yet extensive gaps exist in the knowledge of past fire regimes and structure of whitebark pine forests over much of the species range. This doctoral dissertation research will use a multi-scale approach to elucidate the complex interactions between past fire activity and the composition and structure of whitebark pine forests in the context of different biophysical settings and broad-scale climate variability. Specifically, answers to the following research questions will be sought: What were the historical ranges of variability in the fire regimes of whitebark pine forests throughout the central distribution of the species? What are the driving mechanisms for spatial and temporal variations in fire activity in these forests? How has fire suppression affected the structure of forests characterized by diverse disturbance regimes and biophysical settings? The study sites for this research will be set within three to four watersheds in each of several National Forests and Wilderness Areas along and east-west transect set from southwestern Montana to the Cascades of Oregon. At each site, forest structure and composition data will be obtained through stand surveys and dendroecological sampling, and fire history data will obtained by collecting partial cross sections from fire scarred trees, snags, and down material within the plot and the surrounding area. These data will be used to describe the stand and disturbance history of each site, explore the potential processes that led to these patterns, and compare and contrast these patterns both over time and space. This research will fill both a physical gap in the network of available fire history sites and a theoretical gap in the understanding of mixed-severity fire regimes, the ecosystems they maintain, and the recent ecological changes they have undergone. This research will provide a framework to facilitate the development of management plans to preserve this declining species and the ecosystems it supports. All of the data collected will be archived at the publicly accessible International Tree-Ring Data Bank and the International Multiproxy Paleofire Database, and copies of all publications and reports produced from this project will be disseminated to the offices of each National Forest involved and the Whitebark Pine Ecosystem Foundation. This project will support multiple undergraduate students in field and laboratory settings, strengthening their future employment opportunities. Display samples will be offered as interpretive objects to all National Forest offices involved to help educate the public about the role of fire in whitebark pine ecosystems. A middle school science teacher will also assist in all aspects of this project, thereby garnering experiences in dendroecological research and whitebark pine ecology that he will share with his students.