Written by Joby Warrick. Cross-posted from The Washington Post.

OAK CITY, N.C. — For the sake of a greener Europe, thousands of American trees are falling each month in the forests outside this cotton-country town.

Every morning, logging crews go to work in densely wooded bottomlands along the Roanoke River, clearing out every tree and shrub down to the bare dirt. Each day, dozens of trucks haul freshly cut oaks and poplars to a nearby factory where the wood is converted into small pellets, to be used as fuel in European power plants.

Soaring demand for this woody fuel has led to the construction of more than two dozen pellet factories in the Southeast in the past decade, along with special port facilities in Virginia and Georgia where mountains of pellets are loaded onto Europe-bound freighters. European officials promote the trade as part of the fight against climate change. Burning “biomass” from trees instead of coal, they say, means fewer greenhouse gases in the atmosphere.

But that claim is increasingly coming under challenge. A number of independent experts and scientific studies — including a new analysis released Tuesday — are casting doubt on a key argument used to justify the cutting of Southern forests to make fuel. In reality, these scientists say, Europe’s appetite for wood pellets could lead to more carbon pollution for decades to come, while also putting some of the East Coast’s most productive wildlife habitats at risk.

“From the point of view of what’s coming out of the smokestack, wood is worse than coal,” said William H. Schlesinger, the former dean of Duke University’s Nicholas School of the Environment and Earth Sciences and one of nearly 100 scientists to sign a letter to the Environmental Protection Agency last year asking for stricter guidelines on using biomass to generate electric power. “You release a lot of carbon in a short period of time, and it takes decades to pull that carbon back out of the atmosphere.”

The pellet makers and their supporters dismiss the criticisms, saying their industry will help lower greenhouse gas emissions over time, in part by giving landowners an incentive to plant still more trees. “Healthy markets have contributed to a 50 percent increase in volume of trees since the 1950s, which help offset 15 percent of U.S. carbon emissions annually,” said Gretchen Schaefer, spokeswoman for the National Alliance of Forest Owners, a trade group.

The controversy is prompting renewed scrutiny of a rapidly growing industry that is reshaping Southern landscapes from coastal Virginia to the Gulf of Mexico. All but nonexistent a decade ago, pellet mills have sprung up in seven states to fill galloping demand for renewable fuels to reduce global dependence on coal and petroleum.

What is biomass?

Biomass fuels use energy from plants — corn, used to make ethanol, but also hemp, wood, sugar cane and even yard waste — to produce electric power. Burning plant matter as fuel also releases carbon pollution into the atmosphere, but that carbon can be reabsorbed by new crops, especially in the case of fast growers such as hemp and switchgrass.

As a result, demand for wood pellets is soaring, particularly from the United States. U.S. exports of wood pellets doubled between 2012 and 2014, from 2 million tons to 4.4 million, and climate policies are expected to drive even higher increases over the next decade. After surpassing Canada in 2012, the United States “continues to be the largest wood pellet exporter in the world,” an April report by the U.S. Energy Information Administration stated.

U.S. companies are now racing to keep up with demand. The country’s largest producer of wood pellets, Enviva, based in Bethesda, Md., has built six pellet mills in four states since its founding in 2004 and recently announced plans to build three new ones. The company operates its own deep-water terminal in Chesapeake, Va., loading sea¬going barges with nearly 1.5 million metric tons of wood pellets every year, most of them bound for Britain.

To qualify for European contracts, Enviva must certify that its wood pellets emit 60 percent less carbon pollution than coal, Enviva spokesman Kent Jenkins said. “In fact, our audits show that we produce 80 percent less,” he said.

Unlike other wood-pellet companies that use dedicated pine plantations as their primary source of wood, Enviva buys logging rights from farmers and other private holders. Once the timber rights are secured, Enviva dispatches its crews to harvest the trees and haul the logs and brush to one of its pellet mills.

There, the wood is ground into sawdust and then fed into a machine that uses heat and pressure to create dry pellets, a fuel that can be transported as easily as corn kernels and burned as readily as lignite.

To keep carbon emissions to a minimum, the company makes its pellets from low-quality wood that would be wasted or sold to pulp and paper mills, said Enviva Executive Vice President Thomas Meth.

“We take wood that was meant to be sold but doesn’t have a home,” Meth said. “If you come to our plants, you will see trees that are crooked, diseased or rotten. You can’t use them for saw timber or for a telephone pole.”

Multiple studies support the notion of using discarded wood — the parts of harvested trees that would otherwise be wasted — as a source of biomass fuel. But the problem comes when whole hardwoods are cut down to be burned in power plants, scientists say.

Wood is less energy-dense than coal, so it takes more of it to produce the same amount of electricity. And because oaks and maples mature slowly, it takes decades for new saplings to absorb the amount of carbon dioxide that escapes from a chimney when the trees are burned, scientists say.

“All biomass emits carbon when it’s burned, but when you burn a tree, you’ve liquidated a lot of carbon into the atmosphere and you have to wait a very long time to recapture it,” said Mary S. Booth, an ecologist and director of the Partnership for Policy Integrity, a nonprofit research organization that focuses on biomass energy. “The truth is you’ll never re-sequester all the carbon you release.”

Environmental groups sharply contest Enviva’s claim that it predominantly uses tree waste. Photographs supplied by activists showed trucks entering an Ahoskie, N.C., plant loaded with mature trees. During a visit last week to the plant, a reporter also observed a steady stream of trucks entering the front gate, each hauling trailers stacked with up to 50 freshly cut tree trunks, many of them more than a foot in diameter.

Enviva officials assert that even larger trees qualify as “waste” because they are unsuitable for other uses. In the past, the trees would have been cut and sold for pulp, Meth said. Robert C. Abt, a professor of forestry at North Carolina State University who has extensively studied the pellet industry, acknowledged that companies and their critics often clash over what constitutes “waste” timber.

“Everyone has a reason to be vague about it,” Abt said. “It’s not necessarily scraps from a harvesting operation. It can be a tree that doesn’t have another use, in an economic sense. It might be a tree that is perfectly straight and of a decent size.”

But the bottom line, activists say, is that the companies are using the wrong kinds of trees to make pellets.

“The pellet industry and the [British] utility have been deceptive about the sources of wood they use,” said Derb S. Carter Jr., a Chapel Hill, N.C., attorney with the Southern Environmental Law Center, a nonprofit group that has conducted its own investigation of the company’s practices. “Enviva’s Web site says they’re using only waste wood, but you can follow the trucks to the harvest sites and see what they’re doing.”

The data

Carter’s group recently hired a private research firm to analyze Enviva’s logging practices to measure the net impact on greenhouse gas emissions over a 40-year time scale. Under guidelines set by Britain’s Department of Energy and Climate Change, biomass fuels are required to be “cleaner” than coal, producing no more than 285 kilograms of heat-trapping carbon dioxide for every megawatt of electricity produced.

Because they come from hardwoods, Enviva’s wood pellets fall short of Britain’s standard by a wide margin, according to the research firm, Spatial Informatics Group. An advance copy of the firm’s report was obtained by The Washington Post.

A study last month by the Natural Resources Defense Council reached a similar conclusion about cutting whole trees for fuel. The report found that the practice “can increase carbon emissions relative to fossil fuels for many decades — anywhere from 35 to 100 years.”

“This time period is significant,” a summary of the report stated, continuing, “These emissions will persist in the atmosphere well past the time when significant reductions are needed.”

Enviva officials disputed the reports, saying their own data — backed by independent reviewers hired by the company — shows substantial benefits over coal over the long term. Company officials cited an Agriculture Department report this year that said wood pellets “can deliver very significant greenhouse gas savings, compared to fossil fuels,” when forests are responsibly managed.

“We get audited by our customers frequently, and they know exactly what we do,” Meth said. “We’re very comfortable with our performance from a carbon perspective.”

The concern over emissions is compounded by what ecologists describe as a growing threat to forests and wildlife in the Southeast as demand for wood pellets grows. In North Carolina, the heaviest logging is occurring in flood plains and wetlands that are among the region’s most productive natural habits. In Georgia, where most of the trees for wood pellets are grown on pine plantations, natural forests are rapidly disappearing as landowners see new opportunities to make money, said Ben Larson, forestry and bio-energy program manager for the National Wildlife Federation.

The landscapes most at risk, Larson said, are traditional Southern savannas with a canopy of tall pines and an understory of grass and shrubs that provide food and shelter for wildlife. With more land converted to pines to make wood pellets, the vital understory is disappearing, replaced by stands of fast-growing pines that are raised as a cash drop.

“The result may be more ‘forests,’ but they will mostly be pine plantations,” Larson said. “And that’s bad for wildlife.”