Doctoral Dissertation Research: Factors Affecting Forest Development and Stand Dynamics in Oak Forests in the Eastern U.S.

博士论文研究：影响美国东部橡树林森林发展和林分动态的因素

• 批准号: 1434260
• 负责人: Kurt Kipfmueller
• 金额: $ 1.6万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1434260&HistoricalAwards=false
• 关键词: Doctoral; Dissertation; Research; Factors; Affecting

This doctoral dissertation research project will examine the factors contributing to the observed decline in oak (Quercus) species regeneration across the deciduous forests of the eastern United States. Using a variety of field-based and analytical methods, this project will investigate the multiple factors that may be contributing to decline rates in oak regeneration, including disturbance regime modifications, climatic change, land-use history legacies, and abiotic environmental conditions. Project results will provide much-needed insights into the complex dynamics occurring in oak forests across the eastern U.S., and they will increase theoretical knowledge regarding the ecosystem effects of land-use legacies and multiple, interacting forest drivers, such as canopy disturbances and drought events. Because oak forests offer important ecological, economic, and social benefits to society by producing food and habitat for wildlife, supporting associated vegetative communities, providing valuable timber, and offering scenic opportunities for recreation, this project will assist in the conservation of these benefits by providing information and insights regarding the mechanisms that are reducing the range of oak-dominated forests. The project also should suggest possible forest-management plans to prevent the loss of this important genus. The project will offer special education and training opportunities for undergraduate students who will assist with both field data collection and laboratory analysis. Results from this project will be disseminated broadly through scholarly publications and presentations and through educational outreach activities at land-management offices in the study area. 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.Having dominated eastern deciduous forests for the past 5,000 years, the ecological, commercial, and societal importance of oak forests represents a distinctive long-term legacy across the eastern U.S., but oak species throughout the region are failing to regenerate due to the increased abundance of understory shade-tolerant species that prohibit light from reaching oak seedlings and saplings on the forest floor. The goal of this project is to elucidate the relative importance and the site-specific nature of the multiple forest drivers and to identify interactions among different drivers. The doctoral student will use forest-inventory, dendrochronological, and land-survey analysis methods to investigate multiple drivers of this compositional shift across the Driftless Area in southwestern Wisconsin, an area undergoing significant decreases in oak regeneration. She will examine land surveys from the 1840s and 1940s alongside modern forest inventory data to identify the forest development trajectories occurring throughout the study area. She will employ dendroecological methods to document canopy disturbance histories and to quantify the relationship between climate and radial tree growth. She will use structural equation modeling to analyze the relative influence of land-use legacies, canopy-disturbance history, climate, and site-specific abiotic factors on oak regeneration.

这个博士论文研究项目将研究导致美国东部落叶林中橡树（栎属）物种再生下降的因素。 使用各种基于实地的分析方法，该项目将调查可能导致橡树再生率下降的多种因素，包括干扰制度的修改，气候变化，土地利用历史遗产和非生物环境条件。 项目结果将为美国东部橡树林中发生的复杂动态提供急需的见解，它们将增加关于土地使用遗留问题和多种相互作用的森林驱动因素（如林冠干扰和干旱事件）的生态系统影响的理论知识。 由于橡树林为野生动物提供食物和栖息地，支持相关的植物群落，提供有价值的木材，并提供娱乐的风景机会，为社会提供重要的生态，经济和社会效益，本项目将通过提供有关减少橡树占主导地位的森林范围的机制的信息和见解，帮助保护这些利益。 该项目还应提出可能的森林管理计划，以防止这一重要属的损失。 该项目将为本科生提供特殊教育和培训机会，帮助他们进行实地数据收集和实验室分析。该项目的成果将通过学术出版物和演讲以及研究地区土地管理办公室的教育推广活动广泛传播。 作为博士论文研究改进奖，该奖项还将为有前途的学生提供支持，使其能够建立强大的独立研究事业。过去5,000年来，橡树林在东部落叶林中占据主导地位，其生态，商业和社会重要性代表了美国东部独特的长期遗产，但是，由于林下耐荫物种的增加，阻止了光线到达森林地面上的橡树幼苗和树苗，整个地区的橡树物种无法再生。 该项目的目标是阐明多种森林驱动因素的相对重要性和特定地点的性质，并确定不同驱动因素之间的相互作用。博士生将使用森林资源清查，树木年代学和土地调查分析方法，以调查在威斯康星州西南部的漂流区，这一组成转变的多个驱动因素，该地区正在经历橡树再生显着减少。她将研究19世纪40年代和1940年代的土地调查以及现代森林清查数据，以确定整个研究区域的森林发展轨迹。 她将采用树木生态学的方法来记录树冠干扰的历史，并量化气候和径向树木生长之间的关系。 她将使用结构方程模型来分析土地利用遗产，树冠干扰历史，气候和特定地点的非生物因素对橡树再生的相对影响。