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Heat, wind, and no rain just part of a troubling Western recipe for explosive fires

Published: Saturday, June 30 2012 3:06 p.m. MDT

Climate change suggests an increase in wildfire frequency and greater fire intensity. McInerney said no matter what one believes regarding climate change, the real-life swings experienced in Utah are at the very least something to ponder.

"We are doing climate change if you look at the research," he said. "These conditions are mimicking what these guys have researched."

Both McInerney and Doug Inkley, a scientist with the National Wildlife Federation, said fires are nature's cleansers and aren't necessarily a bad thing.

"Fire is a natural cycle to the environment," McInerney said. "It is a good thing; it changes vegetation."

The problem, Inkley said, is the intensity of the fires playing out in Utah, Colorado and the rest of the West.

"These are like natural fires on steroids," he said. "They are much more intense, very hot and damaging and very patchy."

The fires feed on invasive plants such as cheat grass and burn so hot they leave bare mineral soil exposed, leading to rapid runoff in the spring and more flash flooding. As a result, trees and other vegetation don't have the time to retain as much moisture, and they dry out more quickly in the next go-round.

Inkley said it is a vicious cycle.

"We really have no reason to expect this trend to change at all. Short term, I don't know how we undo it."

Beetle troubles

A steadily warming climate has also tipped the balance in the natural relationship between tree-boring beetles and the trees they infest.

"Spruce beetles and mountain pine beetles have been around for millions of years. They are sort of part of the forest," said Barbara Bentz, a research entomologist with the U.S. Forest Service's Rocky Mountain Research Station. "If you don't have them that suggests something is wrong."

Milder springs, however, have led to a tree mortality rate due to beetle infestations that has not been seen in 150 years, Bentz said.

"It's hard to say if this has happened before and what happens when this happens," because it is outside of modern man's experience, she said.

Swaths of forests full of dead and dying trees play a role in the intensity of wildfires, but there's debate and disagreement in the science and fire communities over the extent of the role.

"There's a lot of controversy over how much difference it makes, but the simple physics can be summarized pretty easily," said Matt Jolley, a fire research ecologist with the Forest Service's Missoula Fire Lab. "When you look at ignition criteria — how much energy it takes to ignite a (beetle)-attacked tree — they ignite faster from the same amount of heat and burn faster."

What can't be ignored is that the infestations — by one beetle species or another —  aren't showing any signs of being effectively controlled by what man can do.

Warmer and drier spring seasons throughout the Western United States have helped the beetles flourish; 6.8 million acres of forests were impacted by infestations of the mountain pine beetle in 2010.

That winter, however, was followed by a record wet and delayed spring that Bentz said for the first time since 2003 caused a substantial decrease in the number of trees killed off by mountain pine beetles.

In Utah, for example, trees killed by mountain pine beetles decreased by 75 percent in 2011.

Spruce beetle kills, however, have remained relatively unchanged in Utah over that two-year period and one Forest Service supervisory entomologist said it will only get worse — with prime recreation places like Big Cottonwood Canyon at risk as the beetles march north.

"I'm very concerned; there's a lot of private property that can't be accessed," said Steve Munson.

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