Planting koa after herbicide application.

Demonstration of tree selection and silviculture to optimize restoration success with koa (Acacia koa)
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.

Close up of acacia psyllid, Acizzia uncatoids.

Can control of acacia psyllids reduce the formation of multiple stems on koa saplings?
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.

Koa gradient study.

Acacia koa gene expression along elevation and precipitation gradients
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.

41 moth leave jbs picture

Effects of koa moth defoliation on Acacia koa plantations
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.

Koa wilt trunk Dudley

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


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


Parent tree selection and wood quality of a 9-year-old Acacia koa stand.
Research on the genetics of koa growth, form, and wood quality by Purdue University graduate student.

caterpillars on koa WH

Caterpillar outbreak hits Hawaii Island forests.
Information on the recent outbreak of native koa looper moth from the Division of Forestry and Wildlife.


Subirrigation as an innovative new technology to reduce water consumption for native plant nursery production.
Purdue University silvicultural experts working with local nurseries to develop new techniques to produce better koa seedlings.


A delay in leaf form transition as a shade avoidance response in two populations of Hawaiian Acacia koa from contrasting environments.
New research project to understand phenotypic plasticity and adaptation of koa trees by Purdue graduate student.


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