The soon-to-open Confluence Energy plant will chip, grind and press into stove-ready pellets upward of 300,000 lodgepole pines a year.

At that rate, it could be decades before the Colorado factory puts a dent in the fast-growing supply of dead trees.

Trees by the millions are going from green to brown to fireplace across the Rocky Mountains. They are felled, essentially, by quarter-inch lumberjacks helped by an extraordinary stretch of mild winters followed by seemingly rainless summers.

The resulting handiwork of the mountain pine beetle is great vistas of once-emerald mountainsides turned into fresh tinder for wildfires, denuded wildlife habitat, and eroding soil that clouds rivers and lakes. That also means a steady timber supply for the Confluence Energy plant being built in Kremmling, Colo.

"It wouldn't work at all," Mark Mathif said of the timber-to-pellet plant he is building, "if it weren't for the beetle."

Meanwhile,

Ips

bark beetles, similar to the pine beetles but not normally as destructive, have converted 50 million bushy pinyon pines in the Southwest into large stands of tinder.

And the emerald ash borer, a Chinese import, has killed 35 million trees and remains an exotic mystery in Michigan.

Tree pests appear to be thriving for a variety of reasons, not all natural.

Climate change could be one factor making trees too weak to fight off attacks they would otherwise survive. Also, forestry practices have concentrated single species of trees together, making them more vulnerable to outbreaks. And generations of fire suppression have left super-thick stands of growth where bugs can scamper more quickly from tree to tree to tree.

"The wild card is climate change," said Tom Fry of the Wilderness Society. "The pine beetle has co-evolved with the trees for thousands of years. They get going in epidemic fashion, and then a hard freeze kills them off. We haven't had that hard freeze in recent years."

The pine-chewing beetles are a native and natural part of the American wilderness. They tend to eat through the trunk of a pine, leaving tiny bore holes and sawdustlike residue at the base of a tree. That's damaging enough, but the real killer is the so-called blue stain fungus that they carry with them - and that often kills a tree within a year.

A healthy tree can withstand a beetle attack, essentially flushing the bugs back out the way they came in with a steady gush of sap. But when a tree is already stressed - primarily by the drought afflicting the West - it can't muster the same defense.

The beetle plague is so widespread - it had damaged just 10,000 Colorado and Wyoming acres in 1997 but spread to 660,000 in the region by last year - that almost nothing can be done to keep it in check. Roughly 825,000 acres of New Mexico's pinyon forests have been lost to the bark beetle.

"Because of the way we've kept out natural fires, you've got too many trees and not enough water," said Dan Ware, a spokesman for the New Mexico state forestry division. "Then drought comes, and they can't survive the beetles."

At Rocky Mountain National Park, where 40,000 acres have been affected, officials concentrate on protecting areas around visitor centers and campgrounds.