由森林大火引起的争论

RENEE MONTAGNE, HOST: This summer's record-breaking wildfire in Yosemite National Park called attention to a problem across the West: forests are overloaded with dense undergrowth which fuel massive forest fires. Lauren Sommer from member station KQED has more.

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LAUREN SOMMER, BYLINE: The forest right after a big fire is incredibly quiet. There are no birds. No bugs. No pine needles rustling in the breeze. Just row after row of blackened trees. Their bark feels like charcoal.

CAROL EWELL: The trees we see here today aren't going to make it.

SOMMER: Forest Service ecologist Carol Ewell is walking through pine trees just outside of Yosemite that saw some of the worst of the Rim Fire.

EWELL: We use the word it was torched. So the fire went all the way up to the top of the crown.

SOMMER: Ewell is here with fire planner Shelly Crook for some fire forensics. The trees here are dense, just three and four feet apart. To Crook it looks like a teenager's bedroom.

SHELLY CROOK: What happens if you let him go three years without cleaning their room? So that's what the forest is and the vacuum cleaner out here is fire.

SOMMER: For decades, the Forest Service tried to put out every fire by 10:00 a.m. the next day. Small trees grew in and during the Rim Fire they became ladders, carrying flames up to the tree tops and leaving just the charred trunks around us. But when we walk just across the road, it looks entirely different.

CROOK: You can kind of see the needles. I'm looking through up there, I see some really bright green healthy needles showing through this canopy.

SOMMER: Crook says the difference is that this area was thinned out, leaving more space between the trees. Allowing fires to burn naturally is the best way to do this, she says. But near homes and towns, contractors thin the forest. It's expensive, even when the larger trees can be sold for lumber.

BRETT STOREY: So what you're seeing right here, this would be where the facility would be.

SOMMER: Brett Storey thinks there's a solution. He's a program manager for Placer County and he's showing me around a recycling facility about 10 miles from Lake Tahoe. His hope is that next year it will also be home to a biomass power plant.

STOREY: Whole towns get heated like this in Scandinavian counties.

SOMMER: The plant would turn tree branches and scrap into a gas that runs a generator, supplying about 1,500 homes with electricity. It will be fueled by Forest Service projects within 30 miles.

STOREY: I kind of joke around - they have this 10-year plan and I call it my supersize menu because it shows what years, how much acreage and what kind of material they're going to be taking out.

SOMMER: Storey says the local utility gets renewable energy and the money helps the Forest Service reduce trees on more land. Under a new policy, California's utilities have to buy electricity from 15 to 20 new small biomass plants like this one. The effort is running into an age-old debate about forest thinning.

KEVIN BUNDY: You can call it thinning, but thinning is really logging.

SOMMER: Kevin Bundy is with the Center for Biological Diversity, an environmental group.

BUNDY: You have to build roads and skid trails and landings. There can be a fair amount of environmental damage associated with thinning operations.

SOMMER: Bundy says biomass power plants would only add pressure to cut trees - trees that are storing carbon as they grow.

BUNDY: When you cut those trees down and burn them for bioenergy, you put all that carbon into the atmosphere, where it warms the climate.

SOMMER: That carbon will eventually be reabsorbed by new trees, but Bundy says the climate can't afford even a short-term increase in emissions.

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SOMMER: Back near Yosemite, signs of life are appearing - like an ant colony coming out of the ash.

STOREY: Ants survive.

SOMMER: Yeah, they made it. Shelly Crook says the green trees around us are just one more reason to deal with California's overloaded forests.

CROOK: It's painfully obvious to me when you look at this, this makes sense. You know, the fire didn't do as much here; the forest is in better condition and it might survive it.

SOMMER: Recovery will take decades, Crook says, but she's hoping the lessons from the Rim Fire will be taken to heart long before then. For NPR News, I'm Lauren Sommer.

MONTAGNE: This is NPR News.