Doctoral Dissertation Research: Long-Term Reconstruction of Oak Mast in the Southern Appalachian Region

栎树(Quercus spp.)在美国东南部的阿巴拉契亚山脉南部，大多数年份都以橡子的形式生产水果。然而，在某些年份，橡子(也被称为桅杆)的产量对一个地区的所有橡树来说都特别重。这些极端的桅杆事件对树木来说是一种巨大的资源消耗，它们对野生动物和野生动物动态产生了深远的影响。开发阿巴拉契亚山脉南部桅杆的详细纵向记录提供了信息，使人们能够科学地检查较长期的桅杆周期的动态，以及是否因气候变化或其他因素而发生了任何变化。这一博士论文研究项目将使用树状年代学桅杆重建的新方法来探索阿巴拉契亚山脉南部橡树桅杆的空间方面。将为阿巴拉契亚山脉南部的几个地点绘制百年桅杆历史，这些重建将用于研究桅杆生产的时间趋势，探索气候和桅杆事件之间的联系，并调查桅杆事件的空间动力学。该项目将生成一套长期橡树年表，这些年表在空间上分布在阿巴拉契亚山脉南部。多年表将通过与该地区20个美国历史气候网(USHCN)气象站的个体林分记录进行比较，对气候对树木生长的影响进行空间分析。该项目将广泛促进树状年代学技术的发展。通过该项目开发的长期桅杆重建将使林学家、生态学家和生物地理学家通过回顾过去更好地了解桅杆生态。该项目还将深入了解尺度在自然系统动力学中的作用。对桅杆在不同尺度上的分析将有助于加深对驱动机构在桅杆动力学中作用的理解。野生动物管理者也可以使用桅杆记录来检查桅杆在过去野生动物种群波动中的作用，生态学家也可以使用桅杆记录来研究极端桅杆事件如何影响橡树种群的建立。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。

Oak trees (Quercus spp.) in the southern Appalachians of the southeastern U.S. produce fruit in the form of acorns in most years. During some years, however, the production of acorns (also known as mast) is especially heavy for all oak trees in an area. These extreme mast events represent a significant resource expenditure for the trees, and they have profound impacts on wildlife and wildlife dynamics. The development of detailed longitudinal records of masting in the southern Appalachians is making available information that permits scientific examination of the dynamics of longer-term masting cycles and whether any changes have occurred in response to climate change or other factors. This doctoral dissertation research project will employ new methods for dendrochronological mast reconstruction to explore spatial aspects of masting in oaks in the southern Appalachians. One hundred-year mast histories will be developed for several locations in the southern Appalachians, and these reconstructions will be used to examine temporal trends in mast production, to explore links between climate and mast events, and investigate the spatial dynamics of mast events. The project will generate a set of long-duration oak chronologies that are spatially distributed throughout the southern Appalachians. Multiple chronologies will enable a spatial analysis of the effect of climate on tree growth by comparing individual stand records with twenty U.S. Historical Climate Network (USHCN) meteorological stations throughout the region. This project will contribute broadly to the development of dendrochronological techniques. The long-term mast reconstructions developed through this project will allow foresters, ecologists, and biogeographers to better understand mast ecology by looking back in time. The project also will add insights into the role of scale in the dynamics of natural systems. The analysis of masting at different scales will enhance understandings of the roles of driving mechanisms in mast dynamics. The mast records also can be used by wildlife managers to examine the role of mast in past wildlife population fluctuations and by ecologists to examine how extreme mast events contribute to oak-establishment pulses. 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.