Missing the Forest for the Trees: Woody Biomass Helps Cut CO2 Emissions
In the debate over fuels for energy production, we’re overlooking the most reliable cleanest option: Our trees.
I’ve studied and written on this issue for more than ten years, and the facts lead me to conclude that sustainably sourced woody biomass is an environmentally sound alternative to fossil fuels such as coal in the United States and beyond.
An analysis I recently published in the Annual Review of Resource Economics explains in detail the economics, environmental benefits, and social acceptance of wood-based energy development in the United States, mirroring the recommendations of the UN Intergovernmental Panel on Climate Change that woody biomass, when grown in sustainably managed forests and harvested following forestry best management practices, could help in mitigating climate change.
Yes, burning wood pellets releases carbon dioxide into the atmosphere. But these emissions are recovered within a year by the new growth on those forestlands which are supporting the continuous production of wood pellets. This creates an overall low-emission electricity generation system. An earlier study estimated that woody biomass from the U.S. Southeast reduces carbon intensity by at least 77% compared to coal if consumed within the country, and between 49% and 72% if the same is shipped abroad for use in countries like the Netherlands.
Certain stakeholder groups assert that woody biomass is more carbon-intensive than fossil fuels. This is because they look at the issue from a tree or a stand-level perspective and ignore the broader forest landscape. They examine an individual tree and conclude that if that tree were cut and used to generate electricity, it would take years to regrow and reabsorb the carbon emitted during electricity generation. Under this assumption, wood pellet-based electricity emits more carbon than coal-based electricity, as demonstrated in a study recently published in Environmental Research Letters.
But examining a forest at a landscape level reveals a more accurate picture, as demonstrated in the same study. Forests are comprised of millions of trees that are all in various stages of growth, decay, and regrowth. When assessing carbon emissions from biomass, what matters is not the fate of individual trees, but whether the forest as a whole is regenerating at a rate sufficient to maintain or increase its overall volume of the wood fiber. If forests are growing at this rate – as they have been for the past 50 years in the Southeast, where the majority of America's wood biomass is sourced – they recapture the carbon emitted by burning wood pellets or any other wood-based energy feedstocks within a year.
As a bonus, as the demand for woody biomass increases, the area under forestlands increases. In fact, one study shows that forestland in the U.S. could increase by 3.4 million acres from 2007 to 2032 under a high-demand scenario for woody biomass and could save 74% to 85% of carbon emissions even after accounting for emissions related to direct and indirect land use changes.
Why would an industry that contributes to the logging of trees increase forests over time? The answer lies in the economics of the larger forest products sector and in the incentive structure for local landowners, which across the US South is overwhelmingly held in private hands. Wood biomass strengthens the market for forestry by providing additional income to landowners who engage in sustainable forestry practices.
Moreover, we have to account for the alternatives that private landowners face when deciding how to use their land. If forestry was not an option, would landowners do nothing with their land and allow trees to mature into natural, old-growth forests? That’s unlikely, given that landowners could use their land for commercial agricultural, or even worse, development. Both options are significantly more carbon-intensive than forestry, as they involve permanently reducing forest acreage, which shrinks the overall carbon sink.
In my view, we should not miss the forest for the trees when it comes to woody biomass. A simplistic view of the issue ignores the realities of the wood products industry, which operates on a large-scale, continuous basis for manufacturing wood-based energy products.
Sustainable wood bioenergy is a worthy replacement for fossil fuels and a vital element of a lower-carbon energy mix, on which the future of our planet relies.
Dr. Puneet Dwivedi is an Associate Professor of Forest Sustainability Sciences at the University of Georgia’s Warnell School of Forestry and Natural Resources in Athens, Georgia. He can be reached at firstname.lastname@example.org or @PuneetDwivedix (Twitter).
Disclaimer: The views expressed in this article are personal in scope, and do not reflect the opinions of the University of Georgia. There are no financial conflicts to disclose.