美国国家公共电台 NPR Chip-And-Ship Forest Clearing May Help Prevent Wildfire Disasters（在线收听）

RYAN HEINSIUS, BYLINE: Large-scale forest restoration designed to prevent wildfires in northern Arizona is behind schedule. One reason why - there are very few places for low-value branches and small diameter logs to go once they've been cut down but are still on the forest floor. It's known as the biomass bottleneck. From member station KNAU in Flagstaff, Ryan Heinsius reports.

HEINSIUS: A huge mechanical claw scoops up several ponderosa pine logs and feeds them into an industrial chipper. Thousands of wood chunks are blasted into a large shipping container.

(SOUNDBITE OF WOOD CHIPPER RUNNING)

HEINSIUS: Overseeing what's fondly known as the chip-and-ship project is Jeff Halbrook with Northern Arizona University's Ecological Restoration Institute.

JEFF HALBROOK: It goes anywhere from one to four to three...

HEINSIUS: Yeah.

HALBROOK: Up to seven small ones can just kind of - and throw in that little jaws there.

HEINSIUS: These trees being fed into the chipper were recently cut from the nearby Coconino National Forest. A crew has been working to pack the shipping containers as tightly as possible, stuffing each with about 40,000 pounds of chipped wood. In about two weeks, nearly 60 containers will arrive at a port in South Korea.

HAN-SUP HAN: They primarily use these wood chips for collection of energy, moving away from the fossil-based energy operation in South Korea.

HEINSIUS: Han-Sup Han teaches forestry at Northern Arizona University. He is hopeful the chip-and-ship project could support global efforts to move toward carbon neutrality and, at the same time, bypass the main roadblock to large-scale forest restoration in the region.

HAN: This material is so small. And it has so low value. As far as hauling this material to the market - has been - economically, it's unfeasible. To be able to complete the restoration of operation, you need to move that out of the forest.

HEINSIUS: This debris is called biomass. And burning it, at least small chunks like this, releases less carbon than traditional coal. The U.S. Forest Service wants to eventually thin a million acres of ponderosa pines vulnerable to wildfire in Arizona. But the agency can't get there without first clearing all that debris. Rich Van Demark is a forester with the Arizona Department of Forestry and Fire Management.

RICH VAN DEMARK: When you fan an acre, you can't go and do another acre until you finish that load of slash or small-diameter material. The bottleneck is essentially not having homes for that lower-value, lower-quality wood.

HEINSIUS: Experts say a lack of domestic markets is mostly to blame for the delays. Biomass-produced energy is expensive. And there just aren't many facilities in the U.S. Plus, the material can be sold in Asia for more than double of what it fetches domestically. That's why forest managers looked overseas for a solution.

VAN DEMARK: As these markets develop and these techniques are refined, we're able to do more acres. And we're way behind the eight ball on our ability to manage acres.

HEINSIUS: Chip-and-ship could eventually export half a million tons of biomass each year. Jeff Halbrook, who's showing me the project, and others are even hopeful it could help restart the long-dormant wood-products industry in northern Arizona.

HALBROOK: We would need to get more workers in the forest, more truck drivers to haul the material here. So our workforce would need to increase before we could really ramp up.

HEINSIUS: Project supervisors acknowledge transporting that much material nearly 6,000 miles across the Pacific would come with a substantial carbon footprint. To offset that, they'd use hundreds of shipping containers that already return empty to Asia from the U.S. If all the pieces fall into place, chip-and-ship could be key for South Korea to move away from fossil fuels while helping make U.S. forests more resilient to wildfire. For NPR News, I'm Ryan Heinsius in Flagstaff.