Intelligent Energy

Forest biofuel increases emissions, study says

Posting in Energy

As the Pacific Northwest looks ahead to next-gen biofuels, new research says the industry should get out of the woods to cut carbon emissions.

The biofuel industry has been seeing the forest for its cellulose, looking for a non-food feedstock to produce fuel for jets and automobiles. In the Pacific Northwest, forest biofuel has been touted as a potential job creator, a means for achieving renewable energy targets, and a way to prevent wildfires.

But a new study says that if cutting carbon emissions is the goal, this biomass—even if just the woody scraps on the forest floor—is the wrong way to go. Publishing yesterday in Nature Climate Change, the researchers find that producing biofuel from forests would release 14 percent more greenhouse emissions than proceeding with current management practices. Harvesting the biomass for just fire prevention would result in a 2 percent increase.

Lead author Tara Hudiburg of Oregon State University says in a statement:

Most people assume that wood bioenergy will be carbon-neutral, because the forest re-grows and there's also the chance of protecting forests from carbon emissions due to wildfire. However, our research showed that the emissions from these activities proved to be more than the savings.

Clearing forests of their underbrush, dead trees, logging remnants and fallen branches might also affect soil health, biodiversity and wildlife habitat. The study, conducted over four years, covers 80 forest types within 19 different eco-regions, such as coastal rainforests and the semi-arid woodlands to the east. About 98 percent of forests in the study region of Washington, Oregon and California are considered carbon sinks. This means they hold more carbon than they naturally release into the atmosphere.

An OSU forestry professor tells the Seattle Post Intelligencer that in the long run, however, the biomass could still be better than burning fossil fuels. In the study, bioenergy production did result in fewer emissions in one scenario: when a forest faces the double whammy of standing in a high fire-risk zone and being weakened by drought or insect infestations, such as the mountain pine beetle. These circumstances, the researchers said, would limit the forest’s future growth and carbon-holding potential. Such forests would also be more likely to burn—and thus, release their carbon—on their own.

Just last month, the USDA granted a total of $80 million to University of Washington and Washington State University for next-gen biofuel research. The projects will investigate the use of poplar plantations as a fast-growing feedstock as well as leftovers from forest thinning and construction sites. On top of finding the right woody resource, developing efficient and economically competitive ways to refine cellulose into fuel remains high on the industry’s to-do list.

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Image: Flickr_Susan_Liepa, Flickr_a75

Melissa Mahony

Contributing Editor

Contributing Editor Melissa Mahony has written for Scientific American Mind, Audubon Magazine, Plenty Magazine and LiveScience. Formerly, she was an editor at Wildlife Conservation magazine. She holds degrees from Boston College and New York University's Science, Health, and Environmental Reporting Program. She is based in New York. Follow her on Twitter. Disclosure