FINAL REPORT Regenerating Longleaf Pine on Hydric Soils: Short- and Long-term Effects on Native Ground-Layer Vegetation SERDP Project SI-1303 June 16, 2009 Joan L. Walker U.S. Forest Service Southern Research Station Susan Cohen U.S. Forest Service Southern Research Station Distribution Statement A:Approved for Public Release, Distribution is Unlimited This report was prepared under contract to the Department of Defense Strategic Environmental Research and Development Program (SERDP). The publication of this report does not indicate endorsement by the Department of Defense, nor should the contents be construed as reflecting the official policy or position of the Department of Defense. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the Department of Defense. SI -1303 Regenerating Longleaf Pine on Hydric Soils: Short- and Long-term Effects on Native Ground-Layer Vegetation Final Report Principal Performers Joan L. Walker U.S. Forest Service Southern Research Station, Clemson, SC Susan Cohen U.S. Forest Service Southern Research Station, RTP, NC Prepared by Joan L. Walker, US Forest Service, Research Plant Ecologist Benjamin O. Knapp, Clemson University, Research Assistant April 22, 2009 1 TABLE OF CONTENTS Page LIST OF ACRONYMS ..................................................................................................... iii LIST OF FIGURES .............................................................................................................v LIST OF TABLES............................................................................................................ vii ACKNOWLEDGEMENTS............................................................................................... ix EXECUTIVE SUMMARY .................................................................................................x 1. Introduction......................................................................................................................1 1.1. Project Context and SERDP Relevance........................................................................1 1.2. Research Questions, Technical Objectives, General Approaches ................................2 1.3. Organization of this report............................................................................................3 2. General Technical Background........................................................................................5 2.1. The longleaf pine ecosystem: habitat loss, Threatened and Endangered (T&E) species, management challenges...................................................5 2.2. Artificial regeneration of longleaf pines.......................................................................5 2.3. Site preparation for artificial regeneration....................................................................6 2.4. Site preparation for pine plantations on to somewhat poorly drained sites ..................7 2.5. Long-term effects of plantation establishment on ground cover composition and structure.............................................................................................9 3. Short-term effects of Longleaf Pine Plantation Establishment......................................11 3.1 Field Experiment Overview: study sites, experimental design, and experimental treatments ........................................................................................11 3.2 Treatment effects on longleaf pine mortality and growth through 20 months ............18 3.2.1 Introduction...............................................................................................................18 3.2.2 Data collection and analytical methods ....................................................................19 3.2.3 Results.......................................................................................................................21 3.2.4 Discussion.................................................................................................................22 3.2.5. Management Implications........................................................................................24 3.3 Relationship of longleaf pine seedling survival and growth to microsite conditions altered by site preparation treatments.........................................................30 3.3.1 Introduction...............................................................................................................30 3.3.2 Data collection and analysis......................................................................................32 3.3.3 Results.......................................................................................................................33 3.3.4 Discussion.................................................................................................................36 3.3.5 Conclusion ................................................................................................................40 3.4. Ground layer vegetation responses to moderate site preparation methods on North Carolina flatwoods sites................................................................50 3.4.1 Introduction .......................................................................................................50 3.4.2 Methods .............................................................................................................51 3.4.3 Results ...............................................................................................................54 3.4.4 Discussion..........................................................................................................58 3.4.5 Conclusion.........................................................................................................61 3.5. Site preparation treatments in wet coastal plain stands affect prescribed 2 fire behavior in young plantations ..............................................................................97 3.5.1 Introduction .......................................................................................................97 3.5.2 Methods .............................................................................................................97 3.5.3 Results .............................................................................................................100 3.5.4 Discussion........................................................................................................102 3.5.5 Conclusion.......................................................................................................103 4. Long-term effects of Longleaf Pine Plantation Establishment....................................115 4.1 Composition and structure of managed pine stands compared to reference longleaf pine sites on Camp Lejeune in the outer coastal plain of North Carolina, USA............................................................................................................115 4.1.1 Introduction .....................................................................................................115 4.1.2 Methods ...........................................................................................................116 4.1.3 Results .............................................................................................................120 4.1.4 Discussion........................................................................................................121 4.1.5 Conclusion.......................................................................................................122 4.2 Using existing growth models to predict RCW habitat development following site preparation: pitfalls of the process and potential growth response .........................................................................................................132 4.2.1 Introduction .....................................................................................................132 4.2.2 Methods ...........................................................................................................133 4.2.3 Results and Discussion....................................................................................135 4.2.4 Conclusion.......................................................................................................138 5. Implications for endangered, threatened, at-risk species (TERS) at MCB Camp Lejeune ................................................................................................146 5.1 Plantation management and restoring RCW foraging habitat ...................................146 5.2 Potential impacts of site-preparation on threatened, endangered, and at-risk species....................................................................................................148 6. Monitoring Experimental Plots....................................................................................154 6.1 Longleaf pines............................................................................................................154 6.1.1 Monitoring objectives......................................................................................154 6.1.2 Field methods ..................................................................................................154 6.1.3 Schedule ..........................................................................................................154