Doctoral Dissertation Research: A Multiscale Analysis of Natural and Human Influences on the Variability of Subalpine Forest Fire History in Rocky Mountain National Park

火是美国西部森林的主要生态因子，因此对森林生态系统的保护和管理具有重要意义。了解森林火灾的频率、大小和严重程度的特征，统称为火灾状况，对于理解和管理西部森林景观是至关重要的。研究人员通过重建过去的火灾来进行火灾历史研究，以确定特定森林类型或区域的火灾状况细节。虽然对美国西部的一些森林类型和地区的火灾状况有详细的了解，但在从怀俄明州南部到新墨西哥州北部的南部落基山脉的亚高山(海拔较高)森林中，人们对火灾状况和人类活动对火灾状况的影响知之甚少。这项博士论文研究项目的目的是为亚高山森林解决以下问题：(1)火灾事件的自然频率、大小和严重程度是什么？(2)不同尺度上对火灾状况的影响是什么，由此导致的火灾状况的空间变化是什么？(3)人类灭火措施如何以及在哪里改变了自然火灾状况？为了解决这些问题，学生将结合树生态(树木年轮)和基于地理信息系统的方法来重建落基山国家公园六个亚高山森林流域近400年的火灾历史。将研究火灾历史记录中的空间和时间变化，以确定由于当地地形、区域气候和人类土地利用实践的影响而在不同尺度上的变化。这些多尺度分析将有助于确定亚高山森林火灾变化的自然范围，不同尺度上影响的相对重要性，以及人类对该森林生态系统的影响。本研究的结果将促进对亚高山森林生态系统动态的认识，这是森林生态系统管理的核心。对灭火活动造成的过度森林燃料积累的关切，加上2002年火季的广泛和严重燃烧，以及该区域森林地区最近人口的急剧增加，导致需要采取森林管理行动，以实现恢复森林和减轻火灾危险的目标。为了准确地确定需要采取各种管理行动的林区，为了集中有限的森林管理资源，需要详细的火灾历史信息。在规划森林火灾恢复和缓解项目方面，该项目将为落基山国家公园和周围的阿拉帕霍-罗斯福国家森林提供重要的决策信息。该项目将为两名本科生的科学发展提供机会，他们将作为研究助理参与该项目。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立研究生涯。

Fire is a major ecological agent in the forests of the western United States, and as a result, it important for forest ecosystem preservation and management. Knowledge of forest fire characteristics of frequency, size, and severity, collectively referred to as the fire regime, is essential to understand and manage western forest landscapes. Researchers conduct fire history research by reconstructring past fires in order to identify fire regime specifics for a particular forest type or zone. Whereas detailed knowledge of the fire regime exists for some forest types and zones of the western United States, in the subalpine (higher elevation) forests of the Southern Rocky Mountains ranging from southern Wyoming to northern New Mexico, relatively little is know about the fire regime and the impact of human activities on the fire regime. The objectives of this doctoral dissertation research project are to address the following questions for subalpine forests: (1) What is the natural frequency, size and severity of fire events? (2) What are the influences on the fire regime at different scales, and what are the resulting spatial variations in the fire regime? (3) How and where have human fire suppression practices altered the natural fire regime? To address these questions, the student will combine dendroecological (tree-ring) and geographic information system-based methods to reconstruct the last approximately 400 years of fire history for six subalpine forest drainage basins in Rocky Mountain National Park. Spatial and temporal variations in this fire history record will be examined to determine variations at different scales as a result of influences from local topography, regional climate, and human land-use practices. These multi-scale analyses will help define the natural range of variability of fire in subalpine forests, the relative importance of influences at different scales, and human impacts on this forest ecosytem.The results of this study will advance knowledge about subalpine forest ecosystem dynamics, which is central to forest ecosystem management. Concern over excessive forest fuel accumulation as a result of fire suppression activities combined with the extensive, severe burning of the 2002 fire season and a recent dramatic increase in human population in the forested areas of the region has resulted in demand for forest management action to achieve goals of forest restoration and fire hazard mitigation. To accurately identify forest areas in need of various management actions and in order to focus limited forest management resources, detailed fire history information is needed. In the context of planning forest fire restoration and mitigation projects, this project will provide important information for decision making for both Rocky Mountain National Park and the surrounding Arapaho-Roosevelt National Forest. This project will provide an opportunity for the scientific development of two undergraduate students who will work on the project as research assistants. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career.