MELISSA BLOCK, HOST:
The mountain forests of the Southwest are burning. Over the past two decades, fires have been setting new records for size and intensity.
NPR's Christopher Joyce reports now on what's causing these mega-fires and how they're changing the face of the Southwest.
CHRISTOPHER JOYCE, BYLINE: Fire scientists are calling it the new normal, a time of fires so big and hot that no one can remember anything like it. One of the scientists who coined that term is Craig Allen. I drive with him to New Mexico's Bandelier National Monument, where he works for the U.S. Geological Survey. We take a dirt road up into the Jemez Mountains, into a landscape of black poles as far as you can see, except that they aren't poles.
CRAIG ALLEN: Every single tree is dead, for miles.
JOYCE: Yeah, you can tell me the next time you see a green tree. I'd like to know the next time you see a live tree.
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JOYCE: This is the Santa Fe National Forest. It's been hammered by fire numerous times since 1996. Last year's Las Conches fire outdid all of them, though. It was the biggest ever in New Mexico since records have been kept. We stop at a high, rocky ridge. Allen jumps out of the car. He's an edgy, active guy with a bowl of brown hair and he can talk for hours about trees. We walk to the edge.
ALLEN: We're looking here at an 800-foot deep canyon with steep canyon walls.
JOYCE: For thousands of years, these mountains have been open forest, mostly grass and Ponderosa pines - a distinctive giant with the bark the color of whole wheat toast and a spray of needles at the top.
ALLEN: What kept those forests open before was the natural process of fire.
JOYCE: Natural fires from lightning burn along the ground, taking out only the shrubs and small trees. But for the last century, the U.S. Forest Service has suppressed almost all fires. They thought fire did more harm than good. The result is the blackened mange below us. More black poles, out to the horizon. It was so intense it reached up into the crowns of these trees and wiped them out.
ALLEN: The heat of the fire creates a convection column, so they looked like an atom bomb going off, actually. They go up until they hit the stratosphere layer often and flatten out anvil-shaped like that, but that convection, as the hot air rises, it's pulling in, at the surface, more oxygen, which is feeding the fire.
JOYCE: Allen takes me to a meadow to show me what's grown since the last three big fires.
ALLEN: This has gone from being a forest for we think probably many thousands of years - a Ponderosa pine forest - to shrubs.
JOYCE: For how long?
JOYCE: And those shrubs just make the next fire burn even faster and hotter. These fires affect people, as well, and not just homes and vacation cabins in the woods.
At a visitors center at the Bandelier monument, the staff is busy trying to stave off flooding. Last year's fire stripped the vegetation from steep hillsides, then the summer monsoon rolled in and flash floods cascaded down the slopes. Bandelier chief ranger, Tom Betts, says a swollen stream almost flooded the park headquarters.
TOM BETTS: It was only about a half an inch of rain and, on a non-fire landscape, we probably wouldn't even have seen much of a rise. As it was, you can see it came up in this area about three and a half feet.
JOYCE: Today, Allen and Betts are figuring out how to deal with the next one.
ALLEN: High water and flood. What does that trigger in terms of management response?
BETTS: A flood triggers shutting down anymore visitor access.
JOYCE: Floods also threaten to wash away the artifacts left here by the Pueblo Indians who lived in caves in these canyon walls. The Forest Service has changed is longstanding policy of no fires. They realized that the fuel buildup was dangerous. Now, they let some burn and start controlled fires to clear out that fuel. They also cut and remove smaller trees, but Allen says they're way, way behind. There will be more big, unstoppable fires.
ALLEN: Nobody is suppressing an active, running crown fire. OK. It's almost political theater, you know, with air tankers, at that point. Air tankers can help in fire retardant at the margins.
JOYCE: But burning embers from big fires leap across those margins and travel for miles. Allen has been studying the Santa Fe forest for 30 years. He feels personally responsible.
ALLEN: This is a part of the world I know best and...
JOYCE: Do you think it's changed forever?
ALLEN: Well, from a human standpoint, yes. Even without climate change in the mix, this is probably not coming back as the forests and woodlands that they were before. It's hard to argue that we didn't fail.
JOYCE: And climate change is likely to make success even more difficult to achieve. Christopher Joyce, NPR News.
BLOCK: And NPR photographer David Gilkey captured the aftermath of these mega-fires. You can see his images at NPR.org and, tomorrow, on MORNING EDITION, we'll examine how climate change, heat, drought and fires conspire to alter the southwestern landscape.