E Mau ana Ka ‘Ohl’a – Perpetuating ‘Ohi’a

New fungal pathogens are threatening the most ecologically and culturally important native tree in Hawai‘i, ‘ōhi‘a (Metrosideros spp.).

Seana Walsh and Dustin Wolkis, National Tropical Botanical Garden

New fungal pathogens are threatening the most ecologically and culturally important native tree in Hawai‘i, ‘ōhi‘a (Metrosideros spp.). Two undescribed taxa of Ceratocystis cause Rapid ‘Ōhi‘a Death (ROD), destroying large stands of ‘ōhi‘a forest on Hawai‘i Island. In preparation for the potential future spread of ROD across the state, seeds of all Metrosideros taxa on all the Hawaiian islands need to be collected, banked, and reciprocated, for resistance testing and for use in potential, future reintroductions. One of the main challenges in initiating a coordinated effort to collect seeds on Kaua‘i is deciding how much seed to collect and from which locations. Seed zones, geographically delineated areas within which seed from originating zone can be transferred to help ensure material is ecologically appropriate for the local environment, were not established in Hawai‘i. Staff from the National Tropical Botanical Garden (NTBG) and Hawai‘i Department of Land and Natural Resources, Division of Forestry and Wildlife, worked together to create generalized provisional seed zones for the island of Kaua‘i. Further, a proposal submitted to the Hawai‘i Tourism Authority by NTBG, to collect, bank and reciprocate seed collections, was supported. Across all 10 seed zones and all four Metrosideros taxa native to Kaua‘i, our collection goal for 2018 is between 6 and 20 million seeds, through both single and bulk seed collections, from over 1,000 individual trees. This work is currently underway.