Skip to content
University of Maryland LibrariesDigital Repository at the University of Maryland
    • Login
    View Item 
    •   DRUM
    • Theses and Dissertations from UMD
    • UMD Theses and Dissertations
    • View Item
    •   DRUM
    • Theses and Dissertations from UMD
    • UMD Theses and Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Distribution and Dynamics of the Evergreen Understory Layer in Central Appalachian Highland Forests

    Thumbnail
    View/Open
    umi-umd-1677.pdf (5.733Mb)
    No. of downloads: 1353

    Date
    2004-07-13
    Author
    Chastain, Robert Arthur
    Advisor
    Townsend, Philip A
    Metadata
    Show full item record
    Abstract
    Evergreen understory layer communities dominated by Rhododendron maximum L. and/or Kalmia latifolia L. may exert significant controls on regeneration of overstory trees, carbon sequestration, and nutrient retention in central Appalachian forests, but their distribution and ecological importance are poorly understood at the regional scale. The distribution, temporal dynamics, and biomass of the evergreen understory layer were examined in the Ridge and Valley and Allegheny Plateau physiographic provinces in the mid-Atlantic Highlands using plot data, remote sensing, dendrochronology, and modeling. First, leaf-off satellite remote sensing and topographic data were applied to map the spatial extent and distribution of R. maximum and K. latifolia with better than 80 percent accuracy. Second, plot data were used to determine the relevant environmental factors and species associations related to the distributions of K. latifolia and R. maximum and assess their influence on forest vertical structure. Cluster analysis and ordination revealed that topo-edaphic gradients and intensity of gypsy moth defoliation were associated with differences in the distribution of these two shrub species within and between the two study areas, and midstory volume was significantly lower where evergreen understory coverage was continuous. Third, variation in K. latifolia and R. maximum growth rates were examined using remote sensing change detection and dendrochronology, and trends were compared to the timing of climatic fluctuations and gypsy moth defoliation of canopy trees. Remote sensing showed that patterns of evergreen understory growth vigor correlated with both defoliation and topographically mediated drought stress. Dendrochronology revealed considerable within-site variability among individual shrubs. However, both releases and suppressions in growth were associated with the timing of gypsy moth defoliation for K. latifolia in both provinces and for R. maximum in the Allegheny Plateau. Finally, carbon sequestration and nutrient storage impacts of these species were estimated by modeling their current aboveground biomass and ecosystem storage influences on several test watersheds. The inclusion of K. latifolia and R. maximum in the ecosystem model NuCSS indicated increases of up to 4825 kg/ha of carbon and 224 kg/ha of nitrogen storage, including notable increases of carbon and nitrogen in the forest floor and soil pools.
    URI
    http://hdl.handle.net/1903/1713
    Collections
    • Biology Theses and Dissertations
    • MEES Theses and Dissertations
    • UMD Theses and Dissertations

    DRUM is brought to you by the University of Maryland Libraries
    University of Maryland, College Park, MD 20742-7011 (301)314-1328.
    Please send us your comments.
    Web Accessibility
     

     

    Browse

    All of DRUMCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister
    Pages
    About DRUMAbout Download Statistics

    DRUM is brought to you by the University of Maryland Libraries
    University of Maryland, College Park, MD 20742-7011 (301)314-1328.
    Please send us your comments.
    Web Accessibility