JUDY WOODRUFF: Now to the wildfires in the American West burning in several states, with the largest ones in New Mexico and Colorado.
In southern New Mexico, fires have burned almost 60 square miles and damaged more than 200 structures. More than 1,000 firefighters in Colorado are trying to contain a fire that has scorched 73 square miles.
NewsHour correspondent Tom Bearden reports from northern Colorado.
TOM BEARDEN: Almost a week after the High Park wildfire began west of Fort Collins, Colorado, the flames still rage out of control. More than 30 homes have been destroyed and evacuations are multiplying.
The federal government just approved the use of seven military tanker planes to assist in the battle. They will add their weight to the attack on fires that have generated massive plumes of smoke like this one looming more than 30,000 feet high over Colorado Highway 74-E.
It's one of the few mountain roads in the area still open, and not far from the town of Red Feather Lakes. As of this morning, the fire had only been 15 percent contained.
Business people like Patti McMillan are counting their losses.
PATTI MCMILLAN, Owner, Red Feather Trading Post: Oh, I think it's going to have a huge impact on everybody.
TOM BEARDEN: McMillan and her husband own the Red Feather Trading Post. And she says business has already started to dry up.
PATTI MCMILLAN: This is summer. This is when we all make our money. This is how we pay our mortgages. And it's going to be tough. It's going to be tough for everybody.
TOM BEARDEN: She says, although it can be terrifying, fire is just part of the landscape here.
PATTI MCMILLAN: It is what it is. We live in the mountains, and it's a fear that we have every year. This year is going to be exceptionally bad. It's been very dry. And when you don't have snow in wintertime, you have this fear. And we just -- you have to live with it. You have to learn to live with it. Everyplace has something. There's tornadoes, there's hurricanes, there's earthquakes. We have fires.
TOM BEARDEN: Colorado also has a lot of dead trees to fuel those fires, raising questions about how the forests have been managed. If you look closely almost anywhere in mountains, it's easy to spot swatches of red, places where insects have killed the most vulnerable trees.
Years of forest policies stopped periodic natural fires from clearing away weak and diseased trees. Forests, in turn, grew much thicker than they had in the past. Trees then had to compete for sunlight and water, leaving some less able to resist attack from insects.
The pine bark beetle has devastated millions of acres of Western forests. And when fires move through those areas, dead trees can cause it to burn hotter and move much faster.
Chad Hoffman is an assistant professor of fire science at Colorado State University. Along with colleagues at the Los Alamos National Laboratory, he's been modeling how fire behaves when it burns in beetle-killed timber.
Chad Hoffman, Assistant Professor of Fire Science, Colorado State University: The first simulation I will show you is of a green forest where the bark beetles haven't been impacted. And what you see is kind of pretty typical, what we might expect as typical fire spread. There's some torching here and there, a little crown fire run going on.
And then, as we compare that to the second simulation, which shows this really broad, high level of mortality of mountain pine needle outbreak, we notice the fire rate of spread increases. It's about double. We see there's a lot more continuous combustion in these simulations.
TOM BEARDEN: A third simulation shows a beetle-damaged area after several years have passed and the needles have fallen to the forest floor.
Some say forests need to be thinned and dead trees removed to reduce fire danger. But that's expensive, and such plans often draw heated opposition from environmental groups.
Douglas Rideout is a professor of forest economics at CSU.
DOUGLAS RIDEOUT, Professor of Forest Economics, Colorado State University: The government is -- has spent and is spending substantial amounts of money on federal lands. I think the real question is, how much should the government be spending on private lands to protect private owners, for which -- I mean, whose responsibility is that, really?
TOM BEARDEN: Rideout says the High Park fire is something of a perfect storm, a very dry winter, high winds fanning the flames, and a great deal of fuel to burn. Add the very difficult terrain, and experts say this fire is likely to keep on burning until the fall.