The search for alternatives to fossil fuels has prompted growing interest in the use of wood, harvested directly from forests, as a carbon-neutral energy source. But a new study by researchers at Duke and Oregon State universities finds that leaving forests intact so they can continue to store carbon dioxide and keep it from re-entering the atmosphere will do more to curb climate change over the next century than cutting and burning their wood as fuel. Substituting woody bioenergy for fossil fuels isn't an effective method for climate change mitigation, according to Stephen R. Mitchell, a research scientist at Duke's Nicholas School of the Environment. Wood stores only about half the amount of carbon-created energy as an equivalent amount of fossil fuels, he explained, so you have to burn more of it to produce as much energy. In most cases, it would take more than 100 years for the amount of energy substituted to equal the amount of carbon storage achieved if we just let the forests grow and not harvest them at all. Because wood stores less carbon-created energy than fossil fuels, you have to harvest, transport and burn more of it to produce as much energy. This extra activity produces additional carbon emissions. These emissions must be offset if forest bioenergy is to be used without adding to atmospheric carbon dioxide concentrations in the near-term. Performing partial harvests at a medium to low frequency – every 50 to 100 years or so – could be an effective strategy. but would generate less bioenergy. The research was funded by a NASA New Investigator Program grant to Kari O'Connell, by the HJ Andrews Long-term Ecological Research Program, and by the Kay and Ward Richardson Endowment.
Contact Tim Lucas, tdlucas@duke.edu