University of Nevada, Reno Dendrochronological Potential of Bermuda Cedar A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geography by Jehren A. Boehm Dr. Adam Csank/Thesis Advisor December, 2019 THE GRADUATE SCHOOL We recommend that the thesis prepared under our supervision by Entitled be accepted in partial fulfillment of the requirements for the degree of , Advisor , Committee Member , Graduate School Representative David W. Zeh, Ph.D., Dean, Graduate School i Abstract The Bermuda cedar, Juniperus bermudiana, is an endangered species endemic to the Bermuda Islands. Likely speciating from a common ancestor of mainland and Caribbean junipers, the Bermuda cedar thrives in the limestone soil and breaks the salty Atlantic wind for less hardy flora. From the time of its establishment on the isolated archipelago until the 15th century, no mammals treaded beneath the Bermuda cedar canopy. The first human use for Bermuda cedar was to repair ships that had wrecked on the treacherous reefs igniting a craze for the valuable lumber. After multiple waves of deforestation and large shifts in land use, conservation of the Bermuda cedar was always an issue and eventually was prioritized by the late 20th century. By 1950 between 90-95% of Bermuda cedars, already competing with multitudes of introduced species, were defoliated and killed by an outbreak of invasive scale leaf insects that were accidentally introduced. Roughly 1% of Bermuda cedars that lived in the 1930’s are still growing today. As a culturally important forestry product since the 17th century an accurate chronology is vital to tell the story of Churches, historic structures and to reconstruct weather and climate that has impacted the Bermuda Islands over the last centuries. To date there has been no successful attempt to create a chronology from this species for historical timber dating or climate reconstruction. Construction of a regional chronology for the island of Bermuda was attempted with 110 cores, 1 partial section, and 1 full section. Using computer assisted cross-dating with independent radiocarbon testing, a statistically robust regional chronology was not successfully created with the samples provided. While a faint common signal was detected amongst Bermuda cedar across the ii territory, more compiled cross sections and geochemical analysis are required to produce a statistically robust regional chronology. iii TABLE OF CONTENTS ABSTRACT .................................................................................................................... i LIST OF TABLES ........................................................................................................ iv LIST OF FIGURES: ........................................................................................................v INTRODUCTION ...........................................................................................................1 STUDY GEOGRAPHY ..................................................................................................5 METHODS ................................................................................................................... 12 RESULTS ..................................................................................................................... 29 DISCUSSION ............................................................................................................... 39 CONCLUSIONS ........................................................................................................... 46 REFERENCES .............................................................................................................. 49 APPENDIX A ............................................................................................................... 52 APPENDIX B ............................................................................................................... 62 iv LIST OF TABLES Table 1 .......................................................................................................................... 35 Table 2 .......................................................................................................................... 65 v LIST OF FIGURES: Figure 1 ...........................................................................................................................3 Figure 2 ...........................................................................................................................6 Figure 3 ...........................................................................................................................7 Figure 4 ...........................................................................................................................8 Figure 5 ......................................................................................................................... 10 Figure 6 ......................................................................................................................... 15 Figure 7 ......................................................................................................................... 16 Figure 8 ......................................................................................................................... 17 Figure 9 ......................................................................................................................... 18 Figure 10 ....................................................................................................................... 20 Figure 11 ....................................................................................................................... 23 Figure 12 ....................................................................................................................... 24 Figure 13 ....................................................................................................................... 30 Figure 14 ....................................................................................................................... 32 Figure 15 ....................................................................................................................... 33 Figure 16 ....................................................................................................................... 36 Figure 17 ....................................................................................................................... 37 Figure 18 ....................................................................................................................... 38 Figure 19 ....................................................................................................................... 45 Figure 20 ....................................................................................................................... 52 Figure 21 ....................................................................................................................... 53 Figure 22 ....................................................................................................................... 54 vi Figure 23 ....................................................................................................................... 55 Figure 24 ....................................................................................................................... 56 Figure 25 ....................................................................................................................... 57 Figure 26 ....................................................................................................................... 58 Figure 27 ....................................................................................................................... 59 Figure 28 ....................................................................................................................... 60 Figure 29 ....................................................................................................................... 61 1 Introduction Motivating science questions This attempt at creating a chronology of Bermuda cedar began as an offshoot of a dendro-provenancing study looking at the timber trade between Bermuda and Continental North America in the 18th and 19th centuries (Kirsten Greer et al., 2019). The National Museum of Bermuda took interest in the ability of dendrochronology to date structural timbers with annual precision and requested a chronology be attempted from the few remaining specimens of Bermuda cedar that still grow in the territory today. Having a master chronology of Bermuda cedar would allow them to date historic structures on Bermuda that were built from local timber. The Conservation Services of Bermuda also saw value in developing a chronology. From their perspective a chronology of Bermuda cedar would aid them in identifying trees that had survived and recovered from the ecological disaster created when scale leaf insects Lepidosaphes newsteadii, Carulaspis minima, and Diapsis carueli defoliated all but a few Bermuda cedars in the 1940s (Challinor & Wingate, 1971; Walker, 1998). The accidental introduction of exotic insects that feed on the photosynthesizing scales of Junipers led to a profound decline in the Bermuda cedar population which had not inherited any resistance from its mainland relatives. A first attempt at reforesting the territory with the related Juniperus virginiana was hopeful to reintroduce a canopy