A tempting option for landowners, Daily said, can be to develop their property into real estate and forget about conservation. A better option, she said, is to offer landowners an income from not just koa but other benefits derived from restoring koa forests.

In her book, she illustrates several examples of how the conservation can make economic sense:

• The city of Napa, Calif., plagued by floods for years, ripped out buildings and bridges a few years ago along the Napa River and restored marshes. The river now spreads out over the wetlands, losing its energy and potential for damage. In a year's time, flood insurance premiums dropped 20 percent while real-estate prices rose 20 percent.

• In 1996, New York City needed to build a new water-purification facility but instead invested in watershed protection 100 miles away, saving billions of dollars. The city pays farmers and landowners to manage their land in a way that's compatible with restoring the watershed. The result has been improved water through natural purification.

• In her own research in Costa Rica, Daily and her collaborators found that coffee plants near an intact rain forest were more productive and that the beans were of higher quality. They linked the finding to the pollination services offered by rain forests where native bees nest.

In Hawai'i, koa forests can provide any number of benefits, Daily said. They can help recharge overdrawn freshwater aquifers with a lush canopy that draws moisture out of the air more efficiently. They can help suppress the spread of fires and control flooding locally, and can store carbon, helping to stabilize the climate globally.

Koa forests also can provide a venue for ecotourism, she said, for visitors who want to take a peek at the rare and endangered species that depend on the koa forest.

Many Hawaiian plants and animals are extinct. Those that remain are dependent on native forest.

"If we can bring back koa, we can help secure the future of those native species that still survive," she said.

One such species is the 'akiapola'au, a highly endangered species of honeycreeper found only on the Big Island.

Liba Pejchar, a postdoctoral researcher working with Daily, made a surprise discovery while completing her doctoral research recently. She found that young koa tree stands are really good habitat for 'akiapola'au. That dispels the belief that old growth is needed to be biologically valuable, as in the case of the spotted owl.

Over the next year Daily plans to delve into the issue from ecological, financial and institutional perspectives. She's working with a varied team of Stanford scholars, including Meg Caldwell and Buzz Thompson in the college's law school, Pamela Matson of the School of Earth Sciences, Roz Naylor in the Stanford Institute for International Studies, and Paul Ehrlich and Peter Vitousek in the Department of Biological Sciences.

Pejchar is leading the ecological efforts and is now surveying native plant and animal diversity on several sites with different degrees of tree cover, including pasture, restored forest and mature forest.

Doctoral student Joshua Goldstein is conducting the financial research. He is working with landowners to develop a financial model that shows which land uses will yield the best balance of profit and ecological benefit.

Goldstein plans to assess such factors as the market price of koa wood, the cost of restoring forest on grazing land — it takes up to 50 years to grow a mature koa tree — and the cultural preferences of ranchers. By putting these factors into a "decision analysis" model, Goldstein hopes to determine which tradeoffs will make koa forest restoration an attractive option.

Daily points out that some landowners already have decided to get into the koa business. One of them is the Big Island's 'Umikoa Ranch, which has planted several hundred acres of koa and is also helping to restore wetlands and nene habitat.