"It's at threat for all kinds of reasons, everything from the commercial value of it, to the depletion of its natural environment, to ranching, agriculture and development," said Samuel Gon, a foundation consultant and senior scientist and cultural adviser for The Nature Conservancy of Hawai'i. "There are also twig bores, pests and fungus that attack the plant."

It is certainly not the first reforestation effort: Kamehameha Schools has spearheaded planting projects on the Big Island, and a landowners' group called the Leeward Haleakala Watershed Restoration Partnership formed in June 2003 to plan ways of recreating a koa forest on about 43,000 acres on Maui.

However, the foundation's project affords a rare opportunity for the public to pitch in with a replanting effort on O'ahu, said Marian Leong, school programs director.

The foundation this week began collecting donations of $10 per koa seedling and has set a goal of raising $50,000 that will help support the planting of 5,000 koa seedlings at Manana.

But because the seedlings and much of the labor have been donated, Leong said, the money will benefit the foundation's educational programs, including those on koa and other native species.

The seedlings are being provided by the Waimanalo nursery and environmental company Hui Ku Maoli Ola.

The nursery crews will be doing much of the planting, but can involve some limited volunteer assistants, said company owner Kapaliku Sherman, who also is a foundation board member.

Sherman said the state is in the process of acquiring about 80 acres of land where the trees are being planted, adding that his company secured permission from the private landowner for the reforestation to begin. The first young trees were planted about a week ago, he said, but work really will begin in earnest in about two weeks.

The site was cleared by a brush fire about five years ago, Sherman said.

Koa trees take about 20 to 30 years to reach maturity, he said.