A vicious cycle is brewing in Utah: Bark beetles are killing a lot of trees in the state. Dead trees are fuel for wildfires, which experts say contributes to global warming. And climate change is now being blamed for an increased population of bark beetles.

The Dixie National Forest bears one of the most obvious signs in Utah of the mark being left by a tiny tree predator commonly known as the bark beetle, a wood-boring insect that in large enough numbers can decimate an entire forest.

"We're talking hundreds of thousands of acres they have basically been wiped out — pretty much the entire spruce component in the Dixie National Forest," said Colleen Keyes, forest-health program manager for Utah Division of Forestry, Fire and State Lands. "It's really something to see. You would be very surprised. It's hard to describe until you see it — it's just dead trees as far as the eye can see."

From 1990 to 2005, just two types of wood-boring beetles affected more than 466,000 acres in Utah.

The huge bark-beetle family includes the Engleman spruce, Douglas fir and mountain pine beetles, native insects that have all been ravaging pine populations throughout Utah and the West. In the Dixie National Forest, it's the spruce beetle, mere millimeters in length, doing the damage.

The U.S. Forest Service's Bark Beetle Technical Working Group calls the bark beetle an "agent of change" in conifer forests in the Rocky Mountain region, noting that the insects can play a critical role in the development and rebirth of Western forests.

In some areas, the beetle's numbers are considered to be in outbreak proportions, with potential negative impacts to recreation, wildlife and watersheds.

"It's very evident — it's very big," Dixie National Forest spokesman Kenton Call said about what the spruce beetle has done.

Most of the forest die-off has happened in recent years, he said. Dixie National Forest workers are now trying to salvage or thin out dead timber, which fits into the Forest Service's "scenery enhancement" project in a heavy-use area where there are cabins.

Call also said the problem with beetles is too big and complex to lay blame in just one or two areas, though he has heard more talk at the highest level of his own agency about the role of global warming.

"We're wrestling with the notion of how we mitigate the impacts of climate change, how we adapt in terms of our management," Call said.