As the European Union works to reduce carbon emissions by moving from coal-fired power plants to renewable fuel sources, countries are increasingly looking to the United States’ southern forests for part of the answer.

Wood pellet mills are sprouting up across the South, including one in Bastrop, turning trees into fuel that is then shipped overseas.

The production of wood pellets, which are then transported from transit centers like the one that recently started operation in Port Allen, rose from 2.8 million tons in 2008 to 19.9 million tons in 2013, according to the U.S. Forest Service. It’s expected that number could get as high as 25.9 million tons by 2020.

The industry has been touted as an environmental improvement, reducing reliance on big pollution sources like coal for so-called “biomass.” But some environmental groups across the South are skeptical, pointing to studies that question whether burning wood pellets actually reduces the release of carbon into the atmosphere. They also are concerned that wood pellet manufacturers will end up cutting down slow-growing, bottomland hardwood instead of quicker-growing species or harvesting scraps.

This concern is particularly acute in other parts of the South. But Louisiana forestry experts say producers in this state are tapping into softwood that comes from forests like north Louisiana’s pine plantations, which would otherwise be cut to feed pulp or paper mills.

Officials with Drax, the British utility that is running pellet operations in Louisiana and Mississippi, said they have targeted areas where paper or pulp mills have closed, providing a new market for pine.

“The fear from some of the environmental groups is the worry for hardwood species,” said Shaun Tanger, assistant professor and extension forest economist with LSU Agricultural Center. “I don’t think it’s disingenuous, but maybe it’s misguided.”

Hardwoods are too valuable as lumber and other products to be harvested for the lower-priced wood pellets, he said. Softwood also is preferred by power plants because it produces less ash and more energy than hardwood.

Tanger said plantation trees need to be thinned for the health of the forest and the remaining trees, after 30 years of growth, can be harvested for lumber.

“That’s where the big payoff is,” Tanger said. “People aren’t going to just manage their land for pulp wood.”

The South was a natural environment for the wood pellet industry to spring up. The logging industry is already in place, and there is access to deepwater ports for shipping overseas. About 62 percent of the pellet production in the United States is taking place in southern states.

In recent months, some southern environmental groups have sought to shine a spotlight on the industry. The Dogwood Alliance, for example, kicked off a tour of southern states to talk about the issue.

Adam Macon, the alliance’s campaign director, said the group is trying to raise awareness about the pellet production process while trying to convince European leaders that wood pellets are not a carbon reduction solution.

“We’re sending a message figuratively and literally to the European policy makers and in the United States that our forests aren’t fuel,” Macon said. “What we’ve turned our attention to is the next biggest threat to southern forests (wood pellet production).”

Macon said the organization disputes claims that the practice is sustainable. Environmentalists also question whether the wood pellet industry actually reduces carbon dioxide in the atmosphere, a key goal for European countries concerned about climate change. They point to recent studies that show the carbon emissions from the industry remain high for decades.

But wood pellet industry supporters say other studies show that the southern pellet industry can be sustainable and reduce greenhouse gases.

Retired Lt. Gen. Russel Honoré, who is a leader of the GreenArmy coalition of environmental groups based in Louisiana, noted the environmental costs of shipping fuel across the Atlantic Ocean.

“Ships burn some of the dirtiest fuel in the world,” Honoré said. Once again, he said, Louisiana has provided economic development subsidies and allowed companies to come into the state to take resources in the names of jobs. Honoré likened the debate to the one over cutting cypress forests for mulch.

“The politicians didn’t change it. Those ‘extreme’ environmentalists changed it,” he said. “This has happened before with our cypress.”

He said the public will have to keep a keen eye on pellet producers to make sure hardwood cypress forests in the Atchafalaya River Basin are not cut.

Officials with Drax, a United Kingdom utility that opened up a pellet transit center in Port Allen and a mill near Bastrop, said they have no interest in hardwood species. Because softwoods pack more energy punch than hardwoods, there’s no reason to go after hardwoods, they said.

When the Bastrop facility hits full stride later this year, the produced wood pellets will go down the Mississippi River to the Port of Greater Baton Rouge and then onto England.

Two of the six generators at the Drax plant in England take wood pellets, and the conversion of a third generator is expected to be finished in 2016.

Once that is done, Drax will be generating 15 percent to 16 percent of the renewable energy in the United Kingdom. As the largest power station in western Europe, the Drax facility provides 8 percent of the energy needs for the country, said Andrew Brown, Drax director of communications.

“Drax in the U.K. is the largest carbon emitter in Europe,” said Pete Madden, Drax U.S. CEO. “The hunt is on to find how we reduce our carbon footprint.”

The plant in Bastrop, along with another near Gloster, Mississippi, could reach 900,000 metric tons a year when in full production, while each of the two current wood pellet generators in the United Kingdom use between 2 million and 2.5 million metric tons of pellets annually.

Both the Mississippi and Louisiana plants are in an area where a paper or pulp mill has closed, allowing in another market for young pine trees in the region.

“We specifically located these in areas with permanently closed mills,” Madden said.

Louisiana Forestry Association Executive Director Buck Vandersteen said the closing of these mills 10 to 15 years ago left a big void for area forest landowners.

“It gives landowners a reason to stay in forestry,” he said of the pellet industry.

To make sure southern forests are not depleted, pellets shipped to England go through two audit procedures to make sure the source of the wood meets a number of requirements, said Richard Peberdy, Drax vice president of sustainability.

“We have to be able to certify to the U.K. regulators that it meets a host of sustainability requirements,” Peberdy said.

The first review is in the United States through the Sustainable Biomass Partnership formed by European utilities using wood pellets for energy. The group uses a certification method to make sure material comes from forests harvested in a sustainable way. The shipment is audited again by an independent auditor once it gets to England, he said.

Madden said Drax is accustomed to receiving coal from all over the world. The fuel to provide energy is going to be shipped into the country no matter what the source, so shipping pellets from the United States doesn’t add to the carbon footprint, he said. The reduction comes from the large amount of carbon dioxide that isn’t released during the burning of coal and by the regrowth of forests in the United States.

Follow Amy Wold on Twitter, @awold10.