AN ABSTRACT OF THE THESIS OF Christina St John for the degree of Master of Science in Sustainable Forest Management presented on October 29, 2018. Title: Addressing Seedling Production Challenges for Hispaniolan Pine and Snowberry Abstract approved: ______________________________________________________ Anthony S. Davis The use of native plants in restoration and afforestation has increased worldwide as their benefits to habitat quality, ecosystem services and local community well-being become widely known. In many restoration and afforestation sites, the most cost-effective and efficient way to establish plants is to use seedlings. Unfortunately, there is a lack of propagation knowledge on how to germinate and grow high- quality seedlings for many native plant species, limiting their production in nurseries and their use in restoration and afforestation. The objectives for this research were to develop protocols for producing two native species important to restoration and afforestation, Hispaniolan pine (Pinus occidentalis) and snowberry (Symphoricarpos albus). Chapter 2 describes a two-part study to develop protocols to germinate and reduce seedborne fungi on P. occidentalis. It was found that the germination of P. occidentalis was unaffected by seed moisture content or cold stratification length and a 1-hour soak in hydrogen peroxide followed by a 1-hour rinse in running water was effective at reducing seedborne fungi without negatively effecting germination. Chapter 3 describes a study on the effect of nursery irrigation on the survival, morphology and physiology of P. occidentalis that experienced various levels of drought. Hispaniolan pine seedlings were subjected to moderate or severe drought preconditioning or were well watered (no preconditioning), then seedlings experienced no drought, moderate drought and severe drought after a simulated planting. Moderate drought preconditioning produced seedlings with higher rates of survival on droughty sites without a decrease in seedling growth when compared to seedlings with no preconditioning or severe drought preconditioning. Chapter 4 describes a study that investigated S. albus seed coat permeability to water and the effect of seed moisture content on stratification requirements needed to break dormancy. Symphoricarpos albus has a water-permeable seed coat. The stratification treatments performed were ineffective at breaking seed dormancy and recommendations for future study are presented. These results will contribute to a growing body of knowledge on how to propagate high-quality seedlings using low-cost and nontechnical methods available to nurseries throughout the world. ©Copyright by Christina St John October 29, 2018 All Rights Reserved Addressing Seedling Production Challenges for Hispaniolan Pine and Snowberry by Christina St John A THESIS submitted to Oregon State University in partial fulfillment of the requirements for the degree of Master of Science Presented October 29, 2018 Commencement June 2019 Master of Science thesis of Christina St John presented on October 29, 2018 APPROVED: Major Professor, representing Sustainable Forest Management Head of the Department of Forest Engineering, Resources and Management Dean of the Graduate School I understand that my thesis will become part of the permanent collection of Oregon State University libraries. My signature below authorizes release of my thesis to any reader upon request. Christina St John, Author ACKNOWLEDGEMENTS I would like to thank Oxbow Farm and Conservation Center for funding this research and allowing me to pursue my passion. A special thanks to Bridget McNassar, Talinna Appling, and the Native Plant Nursery staff for their help, guidance and use of their nursery. I would like to thank all my committee members for their support during an eventful graduate experience. Thank you to my advisor, Dr. Anthony Davis, for being supportive when research projects needed to be rethought and when life outside of grad school got complicated. Thank you to Dr. Jon Souder and Dr. Rakesh Gupta for their support on my committee. Also, a special thanks to Dr. Sabry Elias for his helpful advice on germination studies and hours of seed biology and testing lessons. Thank you to Dr. Jeremy Pinto, Wilman Placido Made and David Allen for supplying the seeds for this project, Scott Orr and Scott Kolpak for the use of their equipment and lab space and Jim Kiser for his equipment support and always checking up on me. The analysis of this data would not have been possible without Ariel Muldoon and Lisa Ganio. Many thanks for Dr. Amy Ross-Davis for her helpful edits. I also want to thank members of the Davis lab group, whose support during moves, research crises, cleaning new workspaces and personal issues was invaluable and kept me strong. A huge thank you to the entire cardiovascular surgery, nursing and rehabilitation staff at Samaritan Health Services who kept me alive and allowed me to fully recover my health this year. Also, a remembrance to one unknown cow, the unsung hero who keeps my blood flowing in the right direction. I am grateful to Sabine Deristen and all nursery workers in Haiti and around the world who inspire us to grow a better world. And, of course, my heartfelt gratitude to my parents and my wonderful partner Barry, who are always by my side when life gets difficult. CONTRIBUTION OF AUTHORS Christina St John and Anthony S. Davis designed the studies. Christina St John collected the data and analyzed it with the assistance of Ariel Muldoon. Christina St John wrote this thesis, with critical revisions by Anthony S. Davis and Amy Ross-Davis. TABLE OF CONTENTS Page 1 General Introduction .................................................................................................................. 1 Hispaniolan pine ................................................................................................................. 4 Snowberry .......................................................................................................................... 6 Literature Cited ................................................................................................................... 8 2 Developing germination protocols for Hispaniolan pine (Pinus occidentalis Swartz) ............... 11 Abstract .............................................................................................................................. 11 Introduction ........................................................................................................................ 12 Dormancy in Western Hemisphere Pines .............................................................. 12 Seed Treatments to Overcome Dormancy ............................................................ 13 Seedborne Pathogens and Their Control .............................................................. 15 Methods ............................................................................................................................. 20 Imbibition Study .................................................................................................... 20 Moisture Content and Cold Stratification Study ................................................... 20 Sanitation Study .................................................................................................... 22 Statistical Analysis ................................................................................................. 22 Results ................................................................................................................................ 24 Imbibition Study .................................................................................................... 24 Moisture Content and Cold Stratification Study ................................................... 24 Sanitation Study .................................................................................................... 25 Discussion ........................................................................................................................... 26 Conclusion ............................................................................................................. 30 Literature Cited ................................................................................................................... 31 3 The effects of preconditioning on survival, growth and water relations of Pinus occidentalis seedlings experiencing drought stress ...................................................................................................... 42 Abstract .............................................................................................................................. 42 Introduction ........................................................................................................................ 43 TABLE OF CONTENTS (Continued) Page Methods ............................................................................................................................. 49 Drought Preconditioning ....................................................................................... 49 Simulated Drought Stress ...................................................................................... 51 Statistical Analysis ................................................................................................. 53 Results ................................................................................................................................ 54 Drought Preconditioning