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

这一博士论文研究项目旨在通过重新创建1978年由Marston首次收集的野外数据集来分析俄勒冈州海岸多个流域内河流木材及其伴随参数的变化，以检查自20世纪80年代初停止采伐以来木材的存在和运输。由于北方斑点猫头鹰被指定为濒危物种，以及西北森林计划法规的实施，森林保护和管理工作的停止归因于增加的森林保护和管理。这种森林保护和随后的植树造林对河流系统的影响目前尚不清楚。30年后，研究人员预计，这些河流木材中的一些已经移动，一些保留下来，一些新的木材已经进口。本研究试图通过对两个现场数据集的比较来回答三个研究问题。(1)1978年至2010年，俄勒冈州海岸山脉流域的河流木材的体积、大小和类型发生了怎样的变化？(2)自1978年以来，这些流域的河流木材发生了哪些河道形态的变化？(3)自1978年以来，植树造林的效果如何改变了河流木材的景观？第四个研究问题认为，使用遥感数据来确定森林流域中是否存在河流木材是目前劳动密集型野外采集方法的替代方法。(4)能否通过机载激光雷达数据分析结合地面参考数据来检测河流木材，以及如何利用这些技术更好地监测河流木材的变化并更好地检验河流木材理论？该项目的结果将为在盆地和盆地间尺度上深入了解俄勒冈海岸山脉的河流木材特征提供帮助。这是一个独特的机会，可以研究三十年间河流中木材的动态，以揭示研究地区发生的植树造林过程。研究结果还将帮助人们了解砍伐带来的一些不太明显的影响，例如树木物种的变化，这些变化显著改变了河流中木材的类型和体积。全球迫切需要研究分水岭规模的河流恢复工作。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修复的关键组成部分，即通过清查河流复杂性来量化河流健康。对实现流域尺度河流相木材研究的一个重要贡献是研究了利用激光雷达数据进行木材识别。这项技术在如此茂密的森林环境中的成功将决定激光雷达图像可用于木材检测的范围。通过博士论文研究改进奖支持这项研究将使一个有前途的学生建立一个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.