The time is now for forests. Forests have demonstrated their value throughout ecosystems, from protecting biodiversity to reducing flooding in cities. Some believe that because forests grow and replenish themselves, they constitute a renewable resource. However, just because a harvested forest can regenerate does not guarantee that other connected systems will do the same.
Researchers Shana M. McDermott, Richard B. Howarth, and David Lutz investigated whether bioenergy—the utilization of organic material—such as trees for fuel—can be a carbon-neutral process in a case study by employing models.
Forests have importance that goes beyond today. The scientists note that because forests are able to store more than one gigaton of carbon annually, they “play an essential role in limiting the future rate of increase of atmospheric carbon dioxide.” Therefore, adjustments to the net carbon sink-source balance caused by the harvesting of a region’s forests for bioenergy are crucial for accurate carbon accounting.
The Northern Forest of the United States, a temperate environment extending from New York to Maine, served as the study’s foundation. There are both private and public landowners, and many of the former have historically harvested their lands for pulp, paper, and timber. There are currently multiple bioenergy power facilities in the area, and there is interest in growing these businesses.
The model utilized by the researchers looks at harvest rates in the Northern Forest as well as rates and advantages of carbon sequestration (carbon sequestration is the process of storing carbon, something trees do exceptionally well.) More carbon is stored in trees as they mature and grow. The tree can no longer absorb it after being chopped down and relocated from the location, and some is released into the sky.
The authors looked at various forest harvesting practices throughout a range of time periods. One technique is clear cutting, which entails clearing the site of all trees. Another would be harvesting over extended periods of time, like 50 years. The length of harvest cycles can vary significantly depending on the type of forest. For instance, a carbon-conscious rotation often lasts 12 years longer than a conventional commercial rotation.
They discovered that the release of carbon during the generation of bioenergy is not climate neutral. Neutrality can be attained when harvest rotations are maximized in accordance with financial and social aims, but this has implications for commercial harvesting.
These findings imply that the conventional wisdom that bioenergy being carbon-neutral is actually untrue. The importance of this discovery may have an impact on regional, national, and local laws as well as harvesting procedures. “This result has potential implications for our regional and national capacity to stabilize levels of atmospheric CO2 and minimize repercussions of climate change,” the scientists write in their conclusion.