A new study by OSU, published in Nature Climate Change, says converting Northwest trees like these into energy will result in a net increase in carbon emissions.
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In a study published today in Nature Climate Change, researchers at OSU suggest that efforts to thin Northwest forests to reduce the risk of wildfire and create biofuels could have an unintended consequence: increasing the region's carbon emissions.
The researchers calculated carbon savings and losses for three different scenarios, ranging from a minimal level of thinning targeted only at reducing fire risk to more intensive thinning scenarios In all three cases, they concluded, thinning would result in greater carbon emissions than current forest management practices in the Northwest. Tara Hudiburg, a PhD candidate at Oregon State University, is the study's lead author.
“We found that if you harvest wood for energy, whether it be for fire prevention or simply for energy itself, the emissions associated with these activities are more than the savings that you get by substituting for fossil fuels,” she said.
Credit: Oregon State University
Hudiburg says that lots of different steps in the process of harvesting forest biofuels resulted in small increases in carbon emissions, ranging from removing a living plant to the energy used to convert it into wood chips or cellulosic ethanol. The crux of the problem, she says, is that woody biomass just isn't a very concentrated form of energy.
"It all kind of comes down to the fact that when you burn the wood or convert it to ethanol, the actually energy output you get is not as high as what you get per unit of fossil fuel" Hudiberg says.
A complete "life cycle analysis" showing the various ways that wood products can be used and their influence on atmospheric carbon -- Oregon State University.
Hudiburg stressed that her study considered forest types in California, Oregon, and Washington. In other regions of the country where forests are less healthy and don't grow as quickly, bioenergy production could be carbon neutral, she says.
Oregon Governor John Kitzhaber has suggested forest bioenergy could be an important engine for rural economic growth, and new source of renewable energy for Oregon. The state currently offers a tax credit for forest biofuels producers.
Tim Raphael is the communications director for the governor. He hadn't read Hudiberg's study. But he says thinning is necessary to reduce the risk of wildfires, and cited other research showing that burning forest biofuels can reduce emissions if it replaces fossil fuel use.
“Helping to continue to grow the emerging biomass energy industry in the state is a policy priority for the governor and any full carbon accounting clearly demonstrates that biomass energy is a net benefit in terms of a carbon footprint.”
Hudiberg agrees that forest thinning has other benefits. But she says, it's important for policymakers to realize the full consequences of thinning and biofuel production policies.
"You’re not always going to be able to have habitat restoration in line with carbon savings" she says.
