Staff

Tami is a CPA whose career has focused on accounting, finance, and taxes. She has a Bachelor of Business Administration from Florida Atlantic University and has lived and worked on Kauaʻi since 1987. Her experience ranges from working 20 years in public accounting with an emphasis on tax and non-profit audits and another 12 years working in the for-profit corporate world before joining the NTBG team in 2014 as the Controller. In 2019 she took over as CFO when Janet Mayfield became the CEO. Ms. Rollins also has served on many non-profit boards over the years.

Janet Mayfield held the position of President and Chief Executive Officer at National Tropical Botanical Garden (NTBG) since 2019 and has dedicated over 25 years to NTBG. She faced an unexpected and life-altering medical event in August of 2025 and after careful consideration, made the deeply personal decision to step down as CEO and transition into a new role as Special Advisor to the CEO. This shift allows her to continue contributing to NTBG while prioritizing her health and well-being.

Janet’s leadership has been foundational to NTBG’s success, and while this transition marks the closing of one chapter, her passion and wisdom will continue to help guide NTBG forward. She will serve in this advisory role until her planned retirement in late 2025, ensuring a smooth and thoughtful transition.

As Director of Science and Conservation for the National Tropical Botanical Garden, Tiffany oversees the strategic development of science and conservation at the Juliet Rice Wichman Botanical Research Center (BRC) at NTBG’s headquarters on Kauaʻi. Tiffany came to NTBG in 2024 from a position as Professor and Head of Department of Species Interaction Ecology in Leipzig, Germany where she continues to have an affiliation. Following her PhD from the University of Pittsburgh, Tiffany held positions and adjunct appointments at the University of Florida, the National Center for Ecological Analysis and Synthesis, Washington University in St. Louis, the Missouri Botanical Garden, and Chicago Botanic Garden. Tiffany is passionate about ecological research and new technologies that can be directly applied to conservation and restoration of plant biodiversity.

Tobias Koehler joined NTBG’s staff in February 2016 as director of its gardens on the South Shore of Kauaʻi. A member of NTBG’s senior management team, he is responsible for the activities within the McBryde and Allerton Gardens, including horticultural care and visitor program, as well as facilities upkeep for these gardens and NTBG’s adjacent headquarters campus.

Mr. Koehler spent nearly a decade in the private sector as an environmental planner, project manager, and operations manager. In addition to his extensive experience in the for-profit world, he has a strong background in non-profit management as well as in marketing, business development, business process improvement, budgeting, financial management, resource management, and contracting.

After completing an undergraduate degree in biology from the University of California at Berkeley and conducting botanical research in Panama and French Polynesia, Mr. Koehler relocated to Hawaiʻi and earned a Master’s degree in botany and one in business administration.

Since January 2020, Lei Wann has been the Director of Limahuli Garden and Preserve. Her ancestral ties to Limahuli and passion to care for Hā‘ena has created a deep connection that shines strongly in her leadership. She is able to share knowledge of the past while bringing in modern research.

Lei Wann went to school at the University of Waikato, the University of Hawaiʻi at Hilo, and the University of Hawaiʻi at Mānoa with degrees in Anthropology, Pacific Island Studies, and Elementary Education. She began her career in conservation, then spent many years in education leading and developing aina based curriculum for keiki at Kawaikini NCPCS and Kamehameha Schools. Currently, she is carrying on her kuleana at Limahuli Garden and Preserve by teaching and perpetuating the biocultural traditions of Hā‘ena.

Michael “Mike” Opgenorth has been the Director of NTBG’s Kahanu Garden and Preserve in Hāna, Maui, since 2015. Mike earned his undergraduate degree in Business Management with a minor in Plant Production/Plant Management from the University of Hawaiʻi at Mānoa. He later achieved his Ph.D. in Horticultural Science from the Natural History Museum of Denmark, University of Copenhagen. Mike’s research focuses on plants of the Pacific, particularly rare and culturally significant species. Using an interdisciplinary approach, his work investigates documentation of plant diversity, human relationships to plants, and their cultivation.

Natalie King joined NTBG as Director of Philanthropy in August 2024, leading our community of steadfast members, donors, funders, and volunteers. With over a dozen years of experience in philanthropy, Natalie holds an educational background in journalism, cultural anthropology, and museum studies. Growing up on Oʻahu, her deep connection to nature and community inspired her passion for biodiversity and biocultural conservation.

Before joining NTBG, Natalie served as Senior Director of Individual Giving at Shedd Aquarium, where she played a pivotal role in advancing philanthropic efforts. She has also led philanthropic initiatives at the Girl Scouts of Greater Chicago and Northwest Indiana, the Smart Museum at the University of Chicago, and the Alpha Phi Foundation.

David is passionate about bringing people and plants together. He served as the Director of Education & Engagement for the California Native Plant Society (CNPS) where he led public programs and campaigns to foster transformative change for people-plant relationships. He led statewide campaigns to build awareness and action for pivotal environmental issues in California, including wildfire, plant poaching, native plant horticulture, and Indigenous stewardship.

Before CNPS, David served as the Director of Visitor Experience at California Botanic Garden. He led the implementation of the first interpretive master plan, oversaw a robust communications calendar, brought the retail nursery online, steered large-scale public events and led the rebranding of the organization. David is continually indebted to mentors from California and Baja California Native communities who have guided his commitment and passion for plant advocacy. David received his BFA from the Rhode Island School of Design and began his career with a formative internship at the Harvard Museum of Natural History, where he got to bring together his love of art and environmental communications.

Brian has nearly two decades of experience working at multiple botanical gardens and various museum settings. Most recently, he was at Fairchild Tropical Botanic Garden, where he co-led The Fairchild Challenge through program development, fundraising and marketing. He previously taught at State College of Florida, Manatee-Sarasota and co-led its Biotechnology Outreach Program. Brian received his Ph.D. in Botany from the University of Wisconsin- Madison, where he studied the evolutionary history and conservation genetics of the Caribbean Basin cardinal airplant. Brian also has his M.S. in Biology through Florida International University and Fairchild’s graduate program. As an FIU alumnus, he is excited by the collaborative opportunities between The Kampong and the International Center for Tropical Botany. Brian volunteered in The Peace Corps in Nicaragua as a Community Environment Promoter after receiving his B.A. in Biology at Colby College.

As Director, he is thrilled to provide leadership and direction to The Kampong – a living botanical garden and museum. He is excited to lead the team in connecting people to plants through enriching experiences focused on discovery, education, horticulture and scientific research.