Doctoral Dissertation Research: A Multi-Scale Analysis of Disturbance Dynamics in Hardwood Forest Communities on the Cumberland Plateau, USA

利用植物区系调查和树木生态学方法对坎伯兰高原次生混交木群落的天然林干扰事件进行研究。这些信息将为小规模自然干扰事件在混交林中个体、种群、群落和生态系统层面形成组成、结构和功能的作用提供见解。在美国东部，大多数间隙尺度的扰动研究都集中在旧生长的遗迹上。由于19世纪和20世纪的自然和人为影响，美国东部的大部分林地都是次生林，混合硬木林。森林扰动动态在原生林和成熟次生林之间可能存在差异。干扰特征和森林响应的差异归因于生物多样性、生物量安排和树龄分布的变化。这项研究将在坎伯兰高原进行，该高原已被列为西半球最多样化和濒危的生态区域之一。不幸的是，缺乏关于坎伯兰高原森林资源和过程的信息。坎伯兰高原生态系统的定量生态信息是当前野生动物栖息地、土地管理、保护和恢复工作所必需的。本研究将首次专门研究坎伯兰高原次生混交林自然间隙尺度干扰的时空格局和森林对这些干扰的响应。研究人员将(1)量化次生混合阔叶林群落的物种组成和林分结构；(2)记录干扰历史和气候对这些群落树木径向生长的影响；(3)量化林隙尺度扰动的时空格局和次生林中不同树种的响应，以确定这些事件对坎伯兰高原阔叶林林分物种组成和结构的影响。了解林分历史和干扰生态学对合理管理森林资源具有重要意义。该项目将量化坎伯兰高原的自然干扰动态和干扰对物种多样性的影响，以帮助该地区目前的保护工作。这个项目的成果将与当地、私人、州和联邦的管理和保护组织共享。树木年轮数据将提供给国际树木年轮数据库，并将增加美国东部存在数据缺口的硬木树种的急需资料。这项研究的结果将在多个学科的专业会议上发表，并将在田纳西州和阿拉巴马州的幼儿园到12年级学生的推广项目中实施。

Floristic inventory and dendroecological methods will be used to investigate natural forest disturbance events in secondary mixed hardwood communities on the Cumberland Plateau. This information will provide insights on the role of small-scale natural disturbance events in shaping composition, structure, and function at the individual, population, community, and ecosystem level in mixed hardwood forests. The majority of gap-scale disturbance studies in the eastern United States have focused on old-growth remnants. Due to natural and anthropogenic influences during the 19th and 20th centuries, most forested lands in the eastern United States are comprised of second-growth, mixed hardwood stands. Forest disturbance dynamics likely differ between old-growth remnants and mature second-growth stands. Differences in disturbance characteristics and forest response are attributed to variations in biological diversity, biomass arrangement, and tree-age distribution. The study will be conducted on the Cumberland Plateau, which has been listed as one of the most diverse and endangered ecoregions in the western hemisphere. Unfortunately, information on forest resources and processes on the Cumberland Plateau is lacking. Quantitative ecological information about Cumberland Plateau ecosystems is needed for current wildlife habitat, land management, conservation, and restoration efforts. This research will be the first to specifically address the spatio-temporal patterns of natural gap-scale disturbances and the forest response to these disturbances in secondary mixed hardwood forests on the Cumberland Plateau. The researchers will (1) quantify species composition and stand structure in secondary mixed hardwood forest communities, (2) document the disturbance history and climatic influences on radial growth of trees these communities, and (3) quantify spatio-temporal patterns of gap-scale disturbances and the response of different tree species in these second-growth stands to determine the influence of these events on species composition and structure in mixed hardwood forest stands on the Cumberland Plateau.Knowledge of stand history and disturbance ecology is important for the proper management of forest resources. This project will quantify natural disturbance dynamics and the influence of disturbance on species diversity on the Cumberland Plateau to aid in current conservation efforts in the region. The results from this project will be shared with local, private, state, and federal management and conservation organizations. Tree-ring data will be contributed to the International Tree-Ring Data Bank and will add much needed information from hardwood tree species in the eastern United States where a data gap exists. The findings of this research will be presented at a number of professional meetings in multiple disciplines and will also be implemented into outreach programs for kindergarten through12th grade students in Tennessee and Alabama.