INFLUENCE OF DOGWOOD ANTHRACNOSE ON FLOWERING · PDF file ecology of flowering dogwood (cornus...

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  • ECOLOGY OF FLOWERING DOGWOOD (Cornus florida L.) IN RESPONSE TO

    ANTHRACNOSE AND FIRE IN GREAT SMOKY MOUNTAINS NATIONAL PARK, USA

    By

    ERIC HOLZMUELLER

    A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT

    OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY

    UNIVERSITY OF FLORIDA

    2006

  • Copyright 2006

    by

    Eric Holzmueller

  • iii

    ACKNOWLEDGMENTS

    I would like to express my thanks to my graduate committee chair, Dr. Shibu Jose,

    for his guidance, suggestions, and support in completing this project. Thanks also go to

    my committee members, Drs. Alan Long, Debbie Miller, and Wendell Cropper, for their

    contributions to this study. Special thanks go to committee member Dr. Mike Jenkins for

    his input, help, and support with all phases of this project. I am also deeply grateful to the

    Great Smoky Mountains National Park Inventory and Monitoring Program for providing

    me with data collection assistance, and an office and housing during multiple field

    seasons. I would also like to thank the faculty at the IFAS-Statistics Division for their

    help in data analyses and Ken Ford for his assistance in the potted plant experiment.

    I would like to thank the National Park Service Southeast Region Natural

    Resources Preservation Program, Great Smoky Mountains Association, and the

    University of Florida College of Agriculture and Life Sciences for providing funding for

    this project. Without their financial support, this project would not have been possible.

    Finally I would like to thank my family and friends for their support and encouragement.

  • iv

    TABLE OF CONTENTS page

    ACKNOWLEDGMENTS ................................................................................................. iii

    LIST OF TABLES............................................................................................................. vi

    LIST OF FIGURES ......................................................................................................... viii

    ABSTRACT.........................................................................................................................x

    CHAPTER

    1 INTRODUCTION ........................................................................................................1

    Statement of the Problem..............................................................................................1 Review of Literature .....................................................................................................2

    Cornus florida .......................................................................................................2 Biology of Dogwood Anthracnose........................................................................3 Impacts of Dogwood Anthracnose ........................................................................4 Factors Affecting Dogwood Anthracnose .............................................................5 Ecological Significance of Cornus florida ............................................................6

    Specific Objectives .......................................................................................................7

    2 INFLUENCE OF FIRE ON THE DENSITY AND HEALTH OF Cornus florida L. (FLOWERING DOGWOOD) POPULATIONS IN GREAT SMOKY MOUNTAINS NATIONAL PARK...........................................................................11

    Introduction.................................................................................................................11 Materials and Methods ...............................................................................................15

    Study Site.............................................................................................................15 Field Sampling.....................................................................................................16 Data Analysis.......................................................................................................16

    Results.........................................................................................................................19 Cornus florida Stem Density...............................................................................19 Foliage Health and Crown Dieback ....................................................................20 Stand Structure ....................................................................................................21 Overstory Community Composition ...................................................................21 Understory Community Composition .................................................................22 Importance Values for Understory Species.........................................................22 Tsuga canadensis Stem Density..........................................................................23

  • v

    Discussion...................................................................................................................23 Management Implications ..........................................................................................28 Conclusion ..................................................................................................................29

    3 INFLUENCE OF CALCIUM, POTASSIUM, AND MAGNESIUM ON Cornus florida L. DENSITY AND RESISTANCE TO DOGWOOD ANTHRACNOSE.....39

    Introduction.................................................................................................................39 Materials and Methods ...............................................................................................41

    Study Site.............................................................................................................41 Forest Soil Sampling ...........................................................................................42 Lab Analysis ........................................................................................................42 Potted Plant Experiment ......................................................................................43 Statistical Analysis ..............................................................................................45

    Forest Soil ....................................................................................................45 Potted Plant Experiment...............................................................................45

    Results.........................................................................................................................45 Forest Soil Cation Saturation...............................................................................45 Potted Plant Experiment ......................................................................................46

    Calcium Treatments .....................................................................................46 Potassium Treatments ..................................................................................46 Magnesium Treatments ................................................................................47 Foliar Cation Concentrations .......................................................................47

    Discussion...................................................................................................................48 Conclusion ..................................................................................................................52

    4 INFLUENCE OF Cornus florida L. ON CALCIUM MINERALIZATION IN TWO SOUTHERN APPALACHIAN FOREST TYPES...........................................64

    Introduction.................................................................................................................64 Materials and Methods ...............................................................................................66

    Study Area ...........................................................................................................66 Field Sampling.....................................................................................................67 Laboratory Analysis ............................................................................................68 Statistical Analysis ..............................................................................................68

    Results.........................................................................................................................69 Forest Floor Mass and Depth ..............................................................................69 Soil pH.................................................................................................................69 Initial Exchangeable Ca.......................................................................................70 Ca mineralization.................................................................................................70

    Discussion...................................................................................................................71 Conclusion ..................................................................................................................76

    5 SUMMARY AND CONCLUSION ...........................................................................83

    LIST OF REFERENCES................................