Logging could result in large amounts of carbon being released from deep in forest soils, according to a new study. It’s a timely report given Europe’s growing embrace of wood as a carbon neutral energy source.

That Europe is relying on wood to meet its renewable energy goal of 20 percent by 2020 might surprise you, but it’s true. As a recent Economist story detailed, “Even in Germany, home of the Energiewende (energy transformation) which has poured huge subsidies into wind and solar power, 38% of non-fossil fuel consumption comes from the stuff.”

What’s often happening is that coal plants are converting at least some of their units to burn wood. Because European countries tend to have stricter laws on logging, a lot of that wood comes from the U.S. South; the Wall Street Journal reported that exports of wood pellets from six Southern states rose from zero to around 700,000 tons in 2011, and then leaped to 1.72 million tons last year.

This rising demand has revived the logging and milling industry in many areas, but it has also brought a new focus on the question of how wood – aka, “woody biomass” or just “biomass” – fits into the renewable energy picture.

The argument for it is that, sure, burning wood releases carbon into the atmosphere – but a fast-growing young tree in the place of the old one removes even more carbon, leading to a net carbon decrease.

The new study, from Dartmouth – unfortunately we only had the press release and abstract to look at – argues that a component often not seen as a factor in this equation, carbon stored deep in soil, could be more important than previously thought.

“Our paper suggests the carbon in the mineral soil may change more rapidly, and result in increases in atmospheric carbon dioxide, as a result of disturbances such as logging,” Dartmouth Professor Andrew Friedland, a co-author, said in a statement. “Our paper suggests that increased reliance on wood may have the unintended effect of increasing the transfer of carbon from the mineral soil to the atmosphere. So the intended goal of reducing carbon in the atmosphere may not be met.”

The complete Dartmouth study, published in the journal Global Change Biology-Bioenergy, is behind a paywall, but you can see the abstract here. In addition, more information on the topic can be found on Friedland’s website.

By Pete Danko