A strong wood-products industry is key to removing thousands of dead, bark beetle-infested trees that threaten to topple onto roads, power lines and campsites or harm watersheds around the West, U.S. Forest Service Chief Tom Tidwell said Monday.

Members of the timber industry, meanwhile, say they need more sustainable sources of logs and a stronger market for them to stay healthy.

Beetles that burrow under the bark of trees have killed about 21.5 million acres in the interior West, or more than 33,000 square miles, Tidwell said at a bark beetle summit hosted by Colorado Gov. Bill Ritter.

The Forest Service estimates about 98,000 trees are falling each day, but government funding can't keep up with how many trees must be cut to protect watersheds, people and infrastructure.

"We have a true crisis on our hands," Ritter said.

Last year, the Forest Service approved $40 million for the outbreak in Colorado, Wyoming and the Black Hills in western South Dakota. About $30 million is going to projects in three national forests in Colorado, where the epidemic has hit hard.

Yet of about 215,000 acres in most immediate need of work, only about 20 percent of the land has been treated, said Antoine Dixon, deputy regional forester for the Forest Service. That makes it imperative for government to get the private sector involved.

"We need an integrated wood products industry to support the conservation work that needs to be done," Tidwell said.

The nation's forests have had bark beetle epidemics before but never one this large, that has spread so fast and has reached such high elevations on trees with no natural resistance, he said.

That's due in part to warmer winters that aren't killing off as many beetles and past fire-suppression policies that allowed thick stands of lodgepole pine to grow.

Beetle-infested trees could be used as biomass for producing energy, but some timber industry executives said the Colorado biofuels market isn't developed enough to create enough demand.

The troubled Intermountain Resources mill in Montrose, which is in receivership, might process some of the felled trees, but costs of hauling trees cut in the north-central Colorado mountains to southwest Colorado are high.

That has left some logs to sit unused as contractors haul them to nearby private land rather than a faraway mill, said Patrick Donovan of Cordes and Co., the mill's receiver.

The mill also has had problems making timber contracts with the Forest Service work out as struggles in the housing industry have affected timber prices, he said.

"We're begging for logs. We're willing to pay for logs, but we can't get logs," Donovan said.

Ritter said the silver lining to the beetle epidemic is looking for economic opportunity that can come from dealing with infested trees.

His summit aimed to set the foundation for how governments, the private sector and nongovernment groups can tackle the hundreds of miles of corridors where dead trees need to be removed, with limited funds.

"Mother Nature bats last. We're just trying to keep the ball game going into extra innings," said Sen. Mark Udall, D-Colo.