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From NPR News, this is ALL THINGS CONSIDERED. I'm Audie Cornish.
MELISSA BLOCK, HOST:
And I'm Melissa Block. Forests in the southwest have become a fuel stockpile. A century of quashing all fires has allowed forests to become overgrown. Now, a warming climate is making the problem worse. Scientists are trying to defuse these green time bombs, but in today's story, part of our series on wildfire and climate, NPR's Christopher Joyce reports on whether that's even possible.
CHRISTOPHER JOYCE, BYLINE: To understand how wrong things have gone in forests outside Santa Fe, New Mexico, you have to see them. Along a trail above the city, the limbs of the Ponderosa pines touch each other. It's not a forest. It's a green fuzzy blanket with young trees fighting for space and light, and it makes William Armstrong sick.
WILLIAM ARMSTRONG: They're a plague. On this forest, it's averaging about 900 trees per acre. Historically, it was probably about 40. Here in the national forest, what we're facing is a tree epidemic.
JOYCE: Armstrong is the U.S. Forest Service's fire manager for the Santa Fe National Forest. He's rubbed some people the wrong way with talk like that. But he says this forest is dangerous. Here's why.
ARMSTRONG: We're standing here on the edge of what is known as the Santa Fe Municipal Watershed. Imagine a huge bathtub...
JOYCE: A natural bathtub sitting in the mountains around Santa Fe. When it rains, the water flows down into reservoirs. That's where the state capital gets most of its water. Trees help slow down the flow, but big wildfires take out the trees. They even burn the soils.
ARMSTRONG: They convert from something that's like a sponge to Saran Wrap. In the aftermath of a wildfire within this watershed, that would flood like the Rio Grande, for heaven's sakes, that would come down a wall of water, and debris and ash and tree trunks, and create devastation in downtown Santa Fe. Suddenly, they find that the entire mountain is in their backyard.
JOYCE: This is the nightmare city managers have in the Southwest: fire, then flash flood. Armstrong's preferred method for preventing big fires is starting his own prescribed fires, ones purposefully lit but controlled. He's done that here. But people didn't like the smoke, and when an intentional fire gets out of control, people sue. Those are some of the reasons the Forest Service is sparing in the use of prescribed fires.
Armstrong wonders what to do next.
ARMSTRONG: How do we reduce the intensity so that these fires are not destructive dragons, but agents of benefit, of recycling nutrients, of maintaining diversity, resiliency? How do we do that?
JOYCE: To find the answer, I drove six hours across the desert up into the pine-covered mountains of Flagstaff, Arizona. I went with ecologist Wally Covington to the Gus Pearson Natural Area. Covington is trimming forests there to make them fireproof. Eighteen years ago, these pine forests had 50 times the number of trees that would have been there naturally.
That's because for most of the 20th century, the U.S. Forest Service put out almost every fire. That allowed small trees to grow like weeds. In a fire, they become ladders that carry flames up into the taller trees and kill them; crown fires, they're called. And the overgrowth doesn't just cause bigger fires. Covington says it also hurts the big trees. There's only so much light and water to go around.
WALLY COVINGTON: The competition with the old growth trees was so intense that those trees started dying at an accelerating rate. It's really amazing that any of these old trees are still hanging on.
JOYCE: So Covington, an ecologist at Northern Arizona University, helped create the Four Forest Restoration Initiative, 4FRI for short. The Forest Service, environmental groups and commercial loggers are partners.
COVINGTON: The goal was to restore as rapidly as possible some facsimile of the natural Ponderosa pine forest.
JOYCE: A forest that would be fire-resistant and healthier.
COVINGTON: Over here, if we walk into this stand, you know, this area that you see right here has obviously been thinned.
JOYCE: It's easy to distinguish the experimental site. Here, they cut out the small trees, leaving a few dozen big ones per acre. They raked up a century's worth of pine needles that had accumulated, they spread grass around, and then they burned it every four years. What they got was an open forest you could ride a horse through at full gallop. That's the way the first settlers described it.
Now, Covington wants to treat hundreds of thousands of acres like this. He hopes that will protect them from big fires, but he doesn't know whether that will work yet. He says they've got to find out fast.
COVINGTON: You know, in my opinion, we need to get as much done as we can in a hurry because fire and crown fire is going to come through these lands faster than we think. You know, this is huge.
JOYCE: The thing is, very little of this treated forest has been put to the test. One section that was is part of the Apache-Sitgreaves National Forest near the town of Greer in eastern Arizona. Last year, the Wallow Fire barreled through half a million acres here, the largest fire in the Southwest since recordkeeping began a century ago.
It hit Greer hard. I went there and talked to Nadine Stanley at a gift shop where she works at the town's Butterfly Lodge museum. She was one of about 2,700 people evacuated from the region.
NADINE STANLEY: We got up on the other side of Salt River Canyon. We looked back. You could see the flames way up in the sky. That was scary. How far away is it? Two hours' driving, so 120 miles.
JOYCE: Part of the area the Wallow Fire consumed was a patch that Wally Covington's team from Northern Arizona University had previously thinned out. They had removed small trees, snags, even shrubs from a hillside. Right next to it, they'd left an overgrown patch intact. One side treated, the other not. When the fire hit, it didn't make a difference.
MICHAEL STODDARD: The intensity of this fire was just so massive, it was just whipping through the trees. It didn't care how continuous these trees were.
JOYCE: That's Michael Stoddard with NAU's Ecological Research Institute. He says the fire jumped a 200-yard-wide meadow and up this hill. The flames arced 50 feet high. The fire front sucked the moisture out of everything ahead of it, so the trees exploded when the fire reached them. The treated area did a little better than the untreated, but it was still cooked.
Ecologist Walker Chancellor is a former firefighter who worked on this NAU project. He says, as they search for ways to prepare the forests, the enemy just gets stronger.
WALKER CHANCELLOR: We have larger fires. We have more fires. We've just gotten into these unprecedented, never-seen-before fire behavior that is scary.
JOYCE: And scientists here say the warming climate will only make things worse. Even without climate change, the size of the job is overwhelming. The 4FRI project has identified 2.4 million acres that need thinning. The Forest Service has started doing that at the Apache-Sitgreaves Forest not far from Greer. Most of the trees here are dead, burned in the Wallow Fire. But they're still fuel for the next fire and have to be removed.
I watch a hot saw machine - kind of a backhoe with giant crablike pincers -grab trees and slice through the stems. It fells half a dozen trees in seconds, but that's not fast enough. The local forest supervisor, Jim Zornes, says the Forest Service doesn't have the money to cut very much. Even if they did, they've got no place to put the timber.
JIM ZORNES: We did have pressure to harvest every dead tree that was left standing within the Wallow Fire. The problem is, we would have so overwhelmed our local industries, the logs would truly have no place to go.
JOYCE: The situation frustrates seasoned fire experts all over the Southwest, especially William Armstrong. He's the Forest Service's fire manager for New Mexico's Santa Fe National Forest. He says thinning isn't enough. The Service literally needs to fight fire with fire, with more prescribed burns or natural fires that are allowed to clear forests without killing them. He says people have to accept some fires or lose control of them.
ARMSTRONG: For a hundred years, we've been very good at suppressing them. And now we're reaping that fiery maelstrom. We have fires now we can't stop. And they're going to continue to burn until the landscape is so scarred and so broken up that there isn't going to be a whole lot left to burn.
JOYCE: Scientists hope they can slow down this epidemic of trees and fire, but it has a century's head start on them. Christopher Joyce, NPR News.
CORNISH: Using data from the U.S. Forest Service, NPR has developed an interactive map that lets you find out what the fire danger is in your area. It's updated every day, and you can find it at npr.org/wildfires.