Doctoral Dissertation Research: Fluvial Wood Presence and Dynamics Over a Thirty-Year Interval in Forested Watersheds

本博士论文的研究项目旨在通过对马斯顿于1978年首次收集的野外数据集的重建，分析多个俄勒冈州海岸山脉流域内河流木材及其相关参数的变化，来研究自20世纪80年代初伐木停止以来木材的存在和运输。伐木停止是由于北方的指定而增加了森林保护和管理斑点猫头鹰作为濒危物种和西北森林计划条例的实施。目前尚不清楚这种森林保护和随后的植树造林对河流系统的影响。30年后，研究人员预计，这些河流木材中的一些已经移动，一些仍然存在，一些新的木材已经进口。本研究试图回答三个研究问题的基础上比较两个领域的数据集。(1)1978年至2010年期间，俄勒冈州海岸山脉流域河流木材的体积、大小和类型如何变化？(2)自1978年以来，这些流域由于河流木材而发生了什么样的河道形态变化？(3)自1978年以来，植树造林的效果如何改变了河流森林的景观？第四个研究问题是利用遥感数据确定森林流域中河流木材的存在，作为目前劳动密集型实地收集方法的替代方法。(4)通过机载激光雷达数据分析结合地面参考数据可以检测到河流木材吗？如何使用这些技术来更好地监测河流木材的变化并更好地测试河流理论？该项目的结果将提供洞察河流木材特性在俄勒冈州海岸范围内的盆地和盆地间的规模。这是一个独特的机会，检查动态的木材在河流中超过三十年的时间间隔，揭示了造林的过程中发生的研究领域。研究结果还将有助于了解皆伐采伐的一些不太明显的影响，例如树种的变化会显著改变河流中木材的类型和数量。迫切需要在全球范围内开展流域规模的河流恢复工作的研究。世界各地的研究人员可能会很好地接受这项工作所呈现的恢复的关键组成部分，即通过河流复杂性的清单来量化河流健康。实现流域尺度河流木材研究的一个重要贡献是使用激光雷达数据木材识别的检查。这种技术在这种极度树木繁茂的环境中的成功将决定激光雷达图像可用于木材检测的程度。通过博士论文研究改进奖对这项研究的支持将使有前途的学生能够建立强大的环境研究事业。

This doctoral dissertation research project seeks to examine both the presence and transport of wood since logging ceased in the early 1980s by analyzing changes in fluvial wood and accompanying parameters within multiple Oregon Coast Range watersheds through the recreation of a field dataset first collected in 1978 by Marston.The cessation is attributed to increased forest conservation and management due to the designation of the Northern Spotted Owl as an endangered species and the implementation of Northwest Forest Plan regulations. The effects of this forest conservation and subsequent afforestation on the river systems are currently unclear. Thirty years later, the researcher expects that some of this fluvial wood has moved, some has remained, and some new wood has been imported. This study seeks to answer three research questions based on the comparison of the two field datasets. (1) How have the volume, size, and type of fluvial wood changed in Oregon Coast Range watersheds between 1978 and 2010? (2) What stream channel morphology changes have occurred due to fluvial wood in these watersheds since 1978? (3) How have the effects of afforestation changed the landscape of fluvial wood since 1978? The fourth research question regards the use of remotely sensed data to determine the presence of fluvial wood in forested watersheds as an alternative to the current labor intensive field collection methods. (4) Can fluvial wood be detected through airborne LiDAR data analysis coupled with ground-reference data, and how can these techniques be used to better monitor fluvial wood changes and better test fluvial theory?The results of this project will provide insight into fluvial wood characteristics in the Oregon Coast Range on a basin and inter-basin scale. This is a distinctive opportunity to examine the dynamics of wood in rivers over a thirty year interval to reveal the process of afforestation that has occurred in the study area. The results will also provide understanding into some less obvious impacts of clear cut harvesting, such as changes in tree species that significantly alter the types and volumes of wood in the rivers. There is an urgent need for research in watershed-scale river restoration efforts globally. Researchers worldwide might very well embrace the key component of restoration which this work renders which is, quantifying stream health through inventory of river complexity. An important contribution to achieving watershed-scale fluvial wood research is the examination of using LiDAR data for wood identification. Success of this technique in such an extremely wooded environment will determine the extents that LiDAR imagery may be used for wood detection. The support of this research through a Doctoral Dissertation Research Improvement award will enable a promising student to establish a strong environmental research career.