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 Kauai 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.

As Director of Science and Conservation for the National Tropical Botanical Garden, Nina oversees the strategic development of science and conservation at the Juliet Rice Wichman Botanical Research Center (BRC) at NTBG’s headquarters on Kauai. Nina came to NTBG in 2019 from a position as Professor and Curator of vascular plants and Director of Science at the Natural History Museum of Denmark, University of Copenhagen, where she continues to be adjunct professor. She is also affiliated with the EECB graduate specialization at the University of Hawaii at Manoa. Following her PhD from the University of Copenhagen, Nina held research fellowships at the Royal Botanic Gardens Kew in the UK and the University of Minnesota. Nina’s research is interdisciplinary and centered on the origin, distribution and conservation of plant diversity and the relationship between people and plants including the role of botanical gardens and collections.

Dr. Ragone was appointed Director of the Breadfruit Institute in 2003 and has worked at the National Tropical Botanical Garden since 1989. She is an authority on the conservation and use of breadfruit, conducting horticultural and ethnobotanical studies on this important Pacific staple crop for 30 years. Her extensive fieldwork on more than 50 islands in Micronesia, Polynesia, and Melanesia enabled NTBG to establish the world’s largest collection of breadfruit. The Breadfruit Institute was created to promote the conservation, study, and use of breadfruit for food and reforestation.

Current research involves collaborative projects in breadfruit agroforestry systems and regenerative agriculture, developing  in vitro methods to conserve and distribute breadfruit cultivars; nutritional salinity studies; molecular and morphological studies to understand taxonomic relationships, origin, and distribution of breadfruit; and ethnobotanical studies on traditional uses of breadfruit in Polynesia and Micronesia.

Dr. Ragone is an Adjunct Professor at the University of Hawai’i in the Department of Tropical Plant and Soil Sciences. She is the author of more than 1000 publications on breadfruit, ethnobotany, horticulture, and native plant conservation. Dr. Ragone holds a Ph.D. and an M.S. in Horticulture from the University of Hawai’i, and a B.S. from Virginia Tech.

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Mr. Michael “Mike” DeMotta has served as head curator for living collections for NTBG organization since the latter part of 2006. He previously served as Horticulturist and then Manager of Living Collections at NTBG’s Limahuli Garden and Preserve.

Mr. DeMotta was born and raised in Honolulu and attended the University of Hawai’i. His interest in horticulture was inherited from his family, and he began growing orchids and ferns at the age of 12. His exposure in school to Hawaiian studies and the art of hula led to a keen interest in native Hawaiian plants, which he began growing in earnest in 1997. During this time he developed many of his own techniques to germinate plants from seeds and cuttings which were otherwise difficult to grow.

In addition to curating the collections for all of NTBG’s gardens and preserves, and overseeing plant records, Mike is responsible for other activities in the Lawa’i Valley Conservation and Horticulture Center, including plant production.

Tobias Koehler joined NTBG’s staff in February 2016 as director of its gardens on the South Shore of Kaua’i. 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 Hawai’i 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 Ha‘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, UH of Hilo, and UH of Manoa 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 Ha‘ena.

Mr. Michael “Mike” Opgenorth came to NTBG in February 2015 with a wide set of skills. In addition to his lifelong background in horticulture, Mr. Opgengorth holds a bachelor’s degree in business administration. He also earned an academic minor in Plant Production/Plant Management from the College of Tropical Agriculture and Human Resources at the University of Hawai’i.

Prior to joining the NTBG team as director of the organization’s Maui garden, Mr. Opgenorth served in numerous capacities at the Hawai’i Department of Agriculture where he worked with a wide range of stakeholders at all levels in Hawai’i’s agriculture community. In his spare time, he works as a tropical plant advisor for a garden lifestyle application, identifying plants from all over the tropical world as well as plant diseases and plant pests.

Heather George joined NTBG as Director of Philanthropy in March 2019. Ms. George has over 20 years of experience working with environmental non-profit organizations as a fundraiser and event coordinator. She is passionate about environmental conservation, science-based resource protection, and communicating the importance of the natural world. Prior to NTBG, Ms. George served as Grants Manager for Waterkeeper Alliance. Previously based in Southern California, she is a graduate of UCLA and has lived on Kauai since 2014.

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.

Mr. Wichman joined NTBG’s staff in 1976, after graduating from NTBG’s Horticultural Internship program. He spent his early career developing Limahuli Garden. During his time as Director there, he obtained a Special Subzone designation in the Conservation District for the entire Limahuli Valley, restored ancient taro terraces, developed a collection of rare and endangered native Hawaiian plants, opened the garden to educational tours, and added the 989-acre Limahuli Preserve. Subsequently Limahuli was named the Best Natural Botanical Garden in the United States by the American Horticultural Society.

In addition to his work in conservation and education, he has led efforts to perpetuate and preserve native Hawaiian culture with projects such as a four-year Indigenous Communities Mapping Initiative Project at Limahuli.

When he assumed leadership of the overall organization as CEO and Director in 2003, and later as President, Mr. Wichman brought renewed focus to NTBG’s conservation and horticulture efforts, and to the native Hawaiian culture.

On January 1, 2019, Mr. Wichman stepped down from the CEO and Director positions but retained the role of President.

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