ELWHA RIVER REVEGETATION 2013: A PLANT PERFORMANCE STUDY by Crescent Calimpong A thesis submitted in partial fulfillment of the requirements for the degree of Master of Environmental Horticulture University of Washington 2014 Program Authorized to Offer Degree: School of Environmental and Forest Sciences Table of Contents List of Figures .................................................................................................................................................. iii List of Tables ................................................................................................................................................... iii Appendix ........................................................................................................................................................... iv ACKNOWLEDGEMENTS .................................................................................................................................. v ABSTRACT ......................................................................................................................................................... 1 KEYWORDS ....................................................................................................................................................... 1 INTRODUCTION ............................................................................................................................................... 1 BACKGROUND .................................................................................................................................................. 3 SITE LOCATION ................................................................................................................................................ 4 HISTORY ............................................................................................................................................................. 5 Native People .................................................................................................................................................................................. 6 Anadromous Fish .......................................................................................................................................................................... 7 Restoration ...................................................................................................................................................................................... 7 SITE CONDITIONS ........................................................................................................................................... 9 Tributaries .................................................................................................................................................................................... 11 Study Site ....................................................................................................................................................................................... 11 Seeding ........................................................................................................................................................................................... 14 STUDY DESIGN ............................................................................................................................................... 15 Research Questions ................................................................................................................................................................... 15 HYPOTHESIS ................................................................................................................................................... 15 METHODS ........................................................................................................................................................ 15 Selection of woody plants and prescriptions ................................................................................................................. 15 Research Design//Plant Tagging ........................................................................................................................................ 16 Vegetation Monitoring ............................................................................................................................................................. 17 Survivorship and Plant condition ....................................................................................................................................... 17 Measurements of growth ....................................................................................................................................................... 18 Large-woody debris .................................................................................................................................................................. 18 Soil Methods ................................................................................................................................................................................. 19 Gravimetric Water Content ................................................................................................................................................... 19 Soil Particle Analysis ................................................................................................................................................................ 20 DATA ANALYSIS ............................................................................................................................................. 20 RESULTS ........................................................................................................................................................... 21 Plant survivorship ..................................................................................................................................................................... 21 Plant Vigor .................................................................................................................................................................................... 23 Plant Growth ................................................................................................................................................................................ 23 Soil Moisture Content ............................................................................................................................................................... 23 Soil Particle Analysis ................................................................................................................................................................ 28 Normalized data ......................................................................................................................................................................... 29 Large-woody debris .................................................................................................................................................................. 31 DISCUSSION ..................................................................................................................................................... 32 Soil Particle Analysis ................................................................................................................................................................ 36 Soil Moisture Content ............................................................................................................................................................... 39 Large-woody debris .................................................................................................................................................................. 40 Areas for further research ..................................................................................................................................................... 40 SUMMARY AND CONCLUSIONS ................................................................................................................. 42 REFERENCES ................................................................................................................................................... 43 APPENDIX ........................................................................................................................................................ 48 ii List of Figures Figure 1. Map of the Elwha River Watershed and former Lake Mills. ............................................... 3 Figure 2. Monthly precipitation averages Elwha Ranger Station. ....................................................... 5 Figure 3. Photo of the valley floor prior to inundation of Lake Mills. Photo courtesy of the Clallam County Historical Society. ........................................................................................................ 10 Figure 4. Map of the sites and plots. .............................................................................................................. 12 Figure 5. Five woody species of the Elwha River watershed. ............................................................. 13 Figure 6. Field technician using a compass to determine plant selection and re-location. ... 17 Figure 7. P. monticola within .5 m of LWD. ................................................................................................. 19 Figure 8.