Mist rises from the ripped-up and muddy earth as moist soil meets chilly morning air. This field deep within in West Virginia's Monongahela National Forest looks more like a battleground than a woodlands restoration project.
This is how Chris Barton is bringing forests back to Appalachia's old strip mines: with a bulldozer tearing up the soil with meter-long metal teeth.
"We've had a lot of people kind of look at us twice," he laughed.
Barton is a forest scientist at the University of Kentucky. On these former mines, he's found that before he can plant a forest, he has to ravage a field.
"The really interesting thing is, after we do it, there's no question that that was the right thing to do," he said.
More on that later. First, Barton's work lies at a crossroads for Appalachia, and for much of the world.
Coal mines have stripped away roughly 400,000 hectares of Appalachian forests.
Burning coal for energy is adding more and more planet-warming carbon dioxide to the atmosphere. As the planet heats up, experts warn that simply cutting greenhouse gas emissions won't be enough to prevent . CO2 must also be removed from the atmosphere.
Currently, experimental machines that pull CO2 directly from the air are too expensive to be practical.
However, a new report from the says effective carbon-removal technology already exists.
It's not rocket science. It's forests.
The report says planting trees and managing forests, along with carbon-absorbing farming and ranching practices, are among the most cost-effective strategies that are ready for large-scale use today.
Taking advantage of these natural systems could take care of more than a third of the greenhouse gas reductions needed to prevent devastating climate change, according to .
In Appalachia, no ecosystem is better at capturing carbon dioxide than red spruce forests.
They're even better than hardwood forests, according to Forest Service soil scientist Stephanie Connolly.
That's because when deciduous trees lose their leaves in the fall, "photosynthesis shuts down and the trees go dormant," she said.
Red spruce is an evergreen. It continues to photosynthesize and pull carbon dioxide out of the atmosphere all winter long.
When evergreen needles do fall, they decompose more slowly than deciduous leaves, she added. And the year-round shade provided by evergreens keeps the soil cool and decomposition slow.
Plus, these forests are more than just carbon sinks. They also absorb water during heavy rains, preventing flooding; and their soils release water during droughts. They provide habitat for rare species like the Cheat Mountain salamander and the northern flying squirrel.
Appalachia has lost 90 percent of the roughly 200,000 hectares of red spruce forest that once blanketed its mountains. Barton, the Forest Service, and a host of partners are working to return red spruce habitat to a thousand-hectare tract of the Monongahela that was strip-mined in the 1980s.
But there's a problem with many of these lands.
After the mines closed, they were restored according to best practices of the time. The leftover rock from mining was packed down to prevent erosion and planted with shallow-rooted grass.
"That's fine for stability," Barton said. "But for plant life, if you went out and planted trees in these sites, they just didn't grow. The ground was way too compacted. Water didn't infiltrate. Roots can't penetrate. Oxygen can't circulate in those environments."
Decades later, lands that had been strip-mined and reclaimed were "stuck." Nothing but grass could grow on them.
Barton figured that ripping up the compacted soil would "unstick" them.
But it wasn't an easy sell.
Jack Tribble was a new forest ranger at Monongahela when Barton and Green Forests Work approached him. Tribble had already tried and failed to get trees to grow on the site.
"These guys came to us and said, 'You need to rip this,'" he said. "Of course, that doesn't make sense at all to me."
But he approved a 30-hectare trial plot and crossed his fingers.
"We [had] a piece of equipment the size of a dozer out there ripping the ground," he said. "That's just kind of a scary thing."
That was 2011. Seven years later, he said, "these trees are just growing really, really well."
"I get it," he added. "I totally get it."
This kind of reforestation is not cheap. Tribble said it costs roughly $5,000 per hectare. He estimates that restoring the most critical areas will add up to about $4 million.