Why Forest-Killing Megafires Are The New Normal
Second of a five-part series
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 they aren't poles. Every single tree is dead. For miles.
"You can tell me the next time you see a green tree," Allen says. "I'd like to know the next time you see a live tree."
This is the Santa Fe National Forest. It's been hammered by fire numerous times since 1996. Last year's Las Conchas fire outdid them all, though. It was the biggest fire 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.
"We're looking here at an 800-foot-deep canyon with steep canyon walls," he says. For thousands of years, these mountains have been open forest: grass and Ponderosa pines, a distinctive giant with bark the color of whole wheat toast and a spray of needles at the top.
"What kept those forests open before was the natural process of fire," Allen says. 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 and more black poles out to the horizon. The Las Conchas fire burned more than 150,000 acres of forest — about twice the area of Manhattan. It was so intense, it reached up into the crowns of these trees and wiped them out.
"The heat of the fire creates a convection column," Allen says. "They look like an atom bomb going off, actually. They go up until they hit the stratosphere layer, often, and flatten out anvil-shaped like that. That convection, as hot air rises — it's pulling in at the surface more oxygen, which is feeding the fire."
Allen takes me to a meadow to show me what's grown since the last three big fires.
"This has gone from being a forest for, we think, probably many thousands of years, a Ponderosa pine forest," he says, "to shrubs. Indefinitely."
And those shrubs just make the next fire burn even faster and hotter. Over the past two decades, fires have been setting new records for size and intensity.
First Fire, Then Flooding
These fires affect people as well, and not just homes and vacation cabins in the woods. At the visitor center at the Bandelier National 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. Flash floods cascade down the slopes.
Bandelier Chief Ranger Tom Betts says a swollen stream almost flooded the park headquarters.
"It was only about a half an inch of rain, and on a nonfire landscape we probably wouldn't even have seen much of a rise," Betts says. "But as you can see, it came up in this area about 3-and-a-half feet."
Today, Allen and Betts are figuring out how to do deal with the next one.
"High water and flood — what does that trigger in terms of management response?" Allen asks Betts.
"Flood triggers shutting down any more visitor access," Betts says. "And we need to shut down utilities — we need to have people get stuff out of their offices."
Floods also threaten to wash away the artifacts left here by the Pueblo Indians, who lived in caves in the canyon walls.
The Forest Service has changed its longstanding policy of "no fires." It realized that the fuel buildup was dangerous. Now it lets some burn and starts "controlled" fires to clear out that fuel. It also cuts and removes smaller trees.
But Allen says the Forest Service is way, way behind. There will be more big, unstoppable fires.
"Nobody is suppressing an active, running crown fire, OK. It's almost political theater, you know, with air tankers at that point," he says. "Air tankers can help, [as can] fire retardant at the margins." 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. "This is a part of the world I know best," he says, admitting the land has changed forever.
"Even without climate change in the mix," he says, "this is not coming back as the forests and woodlands that they were before. It's hard to argue that we didn't fail."
And climate change is likely to make success even more difficult to achieve.
Source: NPR [http://www.npr.org/2012/08/23/159373770/the-new-normal-for-wildfires-forest-killing-megablazes?ft=3&f=1003,1004,1007,1013,1014,1017,1019,1128]