By Anum Yoon

Every year, European countries import millions of tons of wood pellets to burn as fuel. Wood-based biofuel is a rapidly-growing industry driven by the demand for alternatives to fossil fuels.

At first glance, wood seems like an excellent energy source: It’s less scarce than oil and leaves a smaller carbon footprint than coal. As demand grows, though, we have to carefully consider how this popular fuel is impacting the environment.

The Rise of Wood-based Biofuel

The demand for wood pellets in Europe has increased dramatically since the introduction of the European Union’s 2009 Renewable Energy Directive. However, forestry is strictly regulated in Europe, so European countries have turned to the southeastern U.S. to supply their rapidly-growing demand for biofuel.

In 2014, the U.S. exported 4.4 million metric tons of wood pellets to European countries. The U.K. is by far the biggest importer — last year they received 73 percent of U.S. wood pellet exports. Another 19 percent went to Belgium and the Netherlands.

The demand just keeps growing. Some estimates predict that five years from now, Europe will be importing as much as 70 million metric tons of wood to burn. Is it possible to keep up with this astronomical demand without damaging U.S. forests in the process?

Where Does the Wood Come From?

Not all wood-based biofuel comes from sustainable sources like sawdust and tree trimmings. There’s simply not enough of this remnant wood to go around.

Many wood pellet mills in the southeastern U.S. source from mature bottomland hardwood forests. Mississippi, Alabama, Georgia, North Carolina and Virginia are among the states most impacted. Often, multiple pellet mills will harvest from the same patch of forest, creating a hot spot of logging pressure in that area.

Bottomland hardwood forests are a unique type of wetland ecosystem that grows around rivers and streams. They’re dominated by deciduous trees — like oaks, gums and bald cypress — which thrive in frequently-flooded conditions. Due to their broad floodplains, these wetland systems are an essential part of the watershed. They provide a variety of important ecosystem services, including flood control and water purification.

These forests are also an important habitat for a variety of threatened species, including the red wolf, the critically endangered Roanoke logperch and numerous freshwater mussels. They’re also an important migration route for many birds.

The Threat to Forests

Bottomland hardwood forests have already suffered great losses at the hands of agriculture, urbanization and the timber industry, and rising sea levels are an emerging threat to these freshwater swamps. Because only 10 percent of southeastern bottomland forests are fully protected from commercial logging, these habitats are extremely vulnerable to the wood-based biofuel industry.

Mature forests like these can take centuries to regrow, and they may not be the same when they return. Harvesting mature forests does more than just temporarily remove trees — these harvests can change the soil and water quality in an area, which in turn impacts the kinds of species that can inhabit it.

The degradation and removal of forests, especially highly productive wetlands like these, can also have huge and sometimes unpredictable impacts on the carbon cycle. Europe’s efforts to reduce carbon emissions may simply be disrupting the carbon cycle in new ways.

Better Biofuels

Not all biofuels are created equal. We need to reduce our reliance on fossil fuels, but we have to be conscious of what we’re replacing them with and how those new energy sources are impacting the environment.

“It’s not a fossil fuel” shouldn’t be our only criterion for selecting a fuel. No energy source is perfect, but we can do better than harvesting wood pellets from mature forests.

Image credit: Universal Pops

Anum Yoon is a writer who is passionate about personal finance and sustainability. She often looks for ways she can incorporate money management with environmental awareness. You can read her updates on Current on Currency.