Past Projects

Successful reforestation of native Hawaiian forests requires using genetically appropriate seed sources. This study aims to identify the genetic adaptations of koa trees to environmental conditions in different ecosystems in Hawaii.

We hope to discover whether controlling acacia psyllids can reduce the amount of forking in koa seedlings. If so, this may be a silvicultural solution for growing single-stemmed trees that could someday be made into traditional canoes.

Information on the recent outbreak of native koa looper moth from the Division of Forestry and Wildlife.

A new extension project will demonstrate increased koa growth and productivity gained from planting selected koa trees using the best silvicultural practices. We will establish accessible demonstration plantations and develop a practical user-guide.

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.

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.

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.

For his Master’s thesis research at the University of Hawai‘i at Mānoa, Achyut Raj Adhikari is studying two fungal diseases of Acacia koa.

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This study will help us to better understand the effects of the koa moth, Scotorythra paludicola, how long it takes for a koa stand to fully recover, and to expand the knowledge about koa stand dynamics.

Cross-pollination of koa flowers to develop population of known parentage for studying koa wilt genetic markers at the University of Hawaii.

Koa trees often have low forks and inherently poor stem form, which may limit the potential economic and cultural returns from koa forestry. Gap silvicultural techniques may be used to help maintain apical dominance and thereby improve stem form, allowing the possibility to sustainably manage for high value koa (e.g., canoe logs).

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New research project to understand phenotypic plasticity and adaptation of koa trees by Purdue graduate student.

Research on the genetics of koa growth, form, and wood quality by Purdue University graduate student.

Dr. Anna Sugiyama studied intraspecific variation of Acacia koa as part of her post-doctoral research. Specifically, she tested for (1) intraspecific tradeoffs in functional traits, (2) local adaptation and phenotypic plasticity, (3) whether adult traits can predict seedling performance.

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.

Reforestation and forest restoration projects require massive quantities of seeds. Seeds of many legumes, including Acacia koa (koa) require that seeds are scarified (treatment to damage the seed coat to allow water uptake) in order to germinate.

The purpose of this demonstration project was to test the use of a scientifically-proven irrigation technology known as sub-irrigation for native plant nursery production for forest restoration programs in Hawaii.

Koa (Acacia koa) is among the most ecologically and economically valuable hardwood tree species in Hawai‘i and is planted extensively for forest restoration. A relatively high planting density helps to ensure sufficient numbers of surviving seedlings.

Research developments from the Hawaii Agriculture Research Center to develop koa varieties resistant to the deadly koa wilt disease.