Kylle Roy's research at Tropical HTIRC focuses on understanding how ambrosia beetles spread the Rapid ‘Ōhiʻa Death (ROD) fungal disease, threatening the Hawaiian rainforest. Using chemical ecology, Kylle's goal is to develop early detection tools and strategies to manipulate beetle populations, thereby protecting 'ōhiʻa trees from ROD. Her findings underline the importance of creating beetle management strategies, including the potential use of semiochemical repellents, to curb the spread of this devastating disease.
The ʻŌhiʻa Disease Resistance Program (ʻŌDRP), a collaborative effort involving federal, state, and university entities and led by the Akaka Foundation for Tropical Forests, addresses the widespread Rapid ʻŌhiʻa Death (ROD), a fungal disease that has claimed over a million ʻōhiʻa trees in Hawaiʻi since 2010. Discovering certain ʻōhiʻa genotypes with natural resistance to ROD, the initiative now aims to aid forest restoration by supporting private landowners and conservation managers in propagating these resilient plants.
Tawn Speetjens evaluated fertilizer and hosting treatments required to grow healthy ‘iliahi seedlings in the nursery and what types of hosting schemes are necessary to maximize ‘iliahi seedling survival when planting in in barren monotypic pasture landscapes.
Gorse, a hardy shrub, has overwhelmed Mauna Kea's landscape, necessitating creative control methods led by the DHHL and Dr. JB Friday. To increase biodiversity, koa, sugi pine, and redwood trees have been planted post-herbicide and bulldozing in an effort to outcompete the returning gorse. A notable concern is potential frost damage to koa seedlings, as the planting area experiences subfreezing temperatures. To mitigate this, researchers installed temperature sensors to monitor the benefits of gorse rows for insulation. Despite drought risks, over 80% of the koa seedlings planted in May have thrived, offering promising possibilities for future reforestation projects.
Solomon Champion, a PhD candidate at the University of Hawai‘i at Mānoa, is conducting a detailed genetic study of native Hawaiian sandalwood (Santalum L.) to understand gene flow and relatedness among various species and populations, some of which may be threatened by hybridization. The research focuses on fifteen identified populations of Santalum paniculatum, using samples from wild populations and nurseries, and supplements its analysis with additional samples from the Hawaiian Plant DNA Library.
Approximately 16 sandalwood species (Santalum spp.) occur worldwide and at least four sandalwood species and several varieties are native to the Hawaiian Islands, where it is known as ‘iliahi. ʻIliahi is economically and culturally important because of the heartwood’s aromatic essential oil and high value wood for carving. During the early 19th Century, Hawaiian sandalwood was heavily exploited until supplies were depleted. Two species are now relatively common, including S. paniculatum, which is the only species commercially harvested on a limited scale; however, the species have not regained their former abundance or size.
Sandalwoods (Santalum spp.) grow naturally in climates ranging from warm desert in Australia, to a seasonally dry monsoon climate in India, Eastern Indonesia, and Vanuatu, to a subtropical climate without pronounced dry seasons in Hawai‘i and New Caledonia.
Successful tree improvement programs rely on the ability to screen, select, and breed for specific traits. The speed at which a program achieves its goals is often increased with the help of asexual, vegetative propagation, usually in the form of rooting or grafting.
Koa (Acacia koa) is the premier native hardwood of Hawai‘i and a dominant forest species. It provides endangered species habitat, watershed protection, and most of the timber for Hawaii's forest industry. Hawai‘i's forest industry currently relies on harvesting old-growth koa trees from remnant natural forests, and the current supply does not meet the demand.
A limiting factor for native species restoration at high elevation sites in Hawai‘i is exposure of planted seedlings to winter frost. Frost damage reduces survival until seedlings grow tall enough to escape the frost zone concentrated at the soil surface. Artificial frost protection devices, consisting of a single layer of vertically oriented shade cloth placed on the east side of seedlings, may reduce frost damage associated with less radiative cooling.
There is a growing interdisciplinary movement to integrate place-based knowledge and local practices into resource management in Hawaiʻi through community-based approaches. This research explores the underlying conditions for successful implementation of community-managed forests (CMF) in Hawaiʻi, with a focus on how specific land ownership arrangements and assemblage of actors influence the collaborative resource management process and outcomes.
