Koa trees planted at
lower elevations

Researchers are hunting
for koa that can thrive on
former sugar lands

By Rod Thompson
Star-Bulletin

HILO -- University of Hawaii horticulturalist Jim Brewbaker has spent decades hiking the mountains of Hawaii, gathering about 400 kinds of koa seeds.

Thanks to a $40,000 research contract approved by the state Board of Land and Natural Resources recently, he is assured of a place to plant them.

The state made the contract with the Hawaii Agricultural Research Center at Aiea (formerly the Hawaiian Sugar Planters' Association) to find kinds of koa that grow well at low elevations.

The idea is to increase stands of koa on former sugar lands as a source of hardwoods.

Agronomist Bob Osgood at the research center credited Brewbaker with pioneering the effort.

Brewbaker said he's been gathering all kinds of seeds. "I go to Mexico and collect corn seeds," he said.

He has been growing koa at the university's agricultural station at Paauilo on the Big Island's Hamakua Coast since the late 1980s. The station is at about 2,000 feet elevation, about the lower limit of where koa usually grows well.

Osgood says new koa plantings began about four years ago at the Aiea station at 300 feet elevation.

Although koa has a reputation for slow growth, by planting the trees close together researchers got the trees to grow 25 feet high in four years, Osgood said.

They're about four inches thick at present, but will expand in diameter with age, he said.

Both researchers say nature does much of the selecting of good trees for them. Root diseases and insects wipe out the weak trees at low elevations, they said.

Eventually they'll get seeds from the healthy trees and continue looking for really hardy individuals, Osgood said.

Once researchers find koa that grows well at low elevations, it's still a big step for a private investor to put money into a crop that doesn't mature for 20 to 30 years, Osgood said.

A second use of the state money will be to find other crops that can be grown among the koa until the trees are harvestable.

Some of the possibilities to be studied are mushrooms, ornamentals, and native plants such as maile, palapalai, and olena, Osgood said.