In a statement that has raised eyebrows throughout the scientific community, the Environmental Protection Agency says it will begin to count the burning of “forest biomass”—a.k.a. wood—as carbon neutral.
EPA administrator Scott Pruitt describes the policy change as a win for sustainable energy and the forestry industry, providing much-needed clarity with respect to the carbon accounting, thereby “creating valuable jobs and thousands of products that improve our daily lives.”
The problem is, according to many scientists and other industry insiders, using biomass as fuel can exacerbate the challenges we face over climate change by adding carbon emissions to the atmosphere that won’t be reabsorbed by living trees for decades, if ever.
As was highlighted in a Globe Advisors report prepared For the Pacific Northwest Building Resilience Coalition, even though some bio-genic emissions will be reabsorbed by new forest growth over time, there’s no guarantee that they will ever be fully reabsorbed.
This fact was reinforced by a recent commentary form the Smithsonian Institute which noted there are many complicating issues associated with the biomass carbon neutrality assertion.
Among other things, the Institute notes forests need to be properly managed to remain carbon neutral.
A great deal of the wood harvested for use as fuel come from forests that are not sustainably managed. Even trees grown on plantations don’t store the same carbon as natural forests.
As noted in the Globe Advisors study only 51% of original carbon harvested from old growth forests is recaptured after 100 years. It would take well over 100 years for a managed forest to capture the same amount of carbon as a natural forest. But because most plantation forests are harvested at 20-year intervals, it is unlikely they will ever make it to the carbon-neutral point. See chart below.
The Smithsonian commentary also notes that forest carbon is not just stored in the wood of a standing tree. As much as twice the amount is stored in the soil, and the action of logging and harvesting trees cannot occur without impacting the soil. Global warming is already having an impact on soil carbon.
Recent research has shown that microbial activity in warmer soils are increasing the global warming process and soil disturbances from logging only increases the amount of emissions escaping to the atmosphere.
Another concern expressed by many forestry experts is that over reliance on wood as a fuel source could spark widespread clear cutting.
As noted in a Yale Environment 360 article wood pellet demand has led to an increase in logging in the American south and across Europe. It also has fueled illegal old-growth logging in ecologically sensitive areas. As such logging continues to expand, it will undermine the climate goals the regulations are intended to support.
What is also interesting is the timing of the EPA announcement which coincidentally was released only days before National Arbor Day. The EPA’s press release acknowledges that the Agency’s Science Advisory Board has not yet completed its work to develop a workable, applied approach about biomass burning.
More details on the issue of carbon sequestration associated with increased use of forest biomass is available in a series of handouts and report summaries on the Pacific Northwest Building Resilience Coalition website. See here.
