The USDA Forest Service operates at the national, regional, and local levels and must account for a variety of constraints and considerations across its range. Therefore, national-level priorities may not always translate into local-scale management actions. One example of a Forest Service, National Forest System priority area is carbon sequestration.
Carbon sequestration is the process of capturing and storing carbon dioxide (CO2) from the atmosphere. Carbon dioxide is one of the primary gases contributing to climate change, so a reduction in CO2 will help slow global warming.
Forests are highly efficient at converting CO2 to wood through photosynthesis. In light of this, the USDA Forest Service has declared that forest carbon sequestration should be a primary objective of national forest management.
The implementation of this policy requires a translation of national-level strategic goals into local-scale management plans and actions.
Steve McNulty, USDA Southeast Regional Climate Hub Director, worked with colleagues in the Southern Region of the Forest Service to better define a method for converting national policy into local management action.
“While USDA Forest Service strategic planning highlights the need for national forests to sequester carbon, we can’t lose sight of other forest values like recreation, biodiversity, timber, and water yield,” says McNulty.
“We created a methodology for scaling between the national, regional, and local level forest management objectives. It can provide scientific backing for the decisions that foresters make when managing multi-use forests,” says McNulty. The study was published in the journal Climatic Change.
McNulty and his colleagues modeled the proposed methodology, which sequentially considers the constraints and considerations of each policy level, using three case studies from the Southern Region.
At the broadest, national scale, the Forest Service is concerned with forest health. Healthy trees grow faster and can absorb and store more carbon. So generally, good forest health is aligned with maximum carbon sequestration.
At the regional level, the researchers examined specific health concerns.
“The southern region is characterized by ideal forest growing conditions,” says McNulty. “But right now, we are finding that as the South gets warmer and drier, insects and diseases are becoming more of an issue. Take, for example, the southern pine beetle: when trees don’t have enough water, they can’t push the beetles out. So instead the beetles colonize and kill the trees.”
In response, forest managers often use prescribed burns to halt beetle outbreaks and keep the forests healthy.
Prescribed burns do align with carbon sequestration goals. Though some carbon dioxide is lost initially when forest biomass is burned, renewed growth rates follow a burn and result in an overall increase in carbon storage.
“When you remove vegetation, you also reduce water demand. Remaining trees have more available water and less competition and can maintain resilience against other disturbances,” explains McNulty.
The study considered three case studies in North Carolina to showcase different situations that can complicate the pro-burning, pro-carbon sequestration story:
- The Southern Appalachian mountains have some of the most varied climate and topography in the U.S. These environmental conditions lead to a wide variety of plants and animals within the area. Forest clearing is a tool often used to maintain early successional habitats (i.e., young forests) that facilitate such diversity, but the maintenance of open space is not ideal for forest carbon sequestration. Therefore, these forests may be better prioritized for maintaining biodiversity rather than trying to increase forest carbon storage.
- Southern Atlantic coastal forests near urban areas could benefit from prescribed burns that would help restore fire-adapted species and protect endangered wildlife habitat. However, air quality regulations and concerns for human health limit the use of prescribed fire in or around populated areas. Forest recreation may be a better priority for these forests.
- Rural Southern Atlantic coastal forests could benefit similarly from prescribed burning and are less constrained by air quality limitations. These forests represent a local condition that can optimize for the sequestration of carbon.
“These three examples show how local objectives sometimes line up with national ones, while other times there are overriding considerations that will dictate a forest management plan that is different from a national strategy,” says McNulty. “This methodology gives consideration to all objectives and provides forest managers with a scientific basis for making management decisions at the site scale.”
For more information, email Steve McNulty at email@example.com.