Forests are the largest terrestrial carbon sink in the world, absorbing carbon dioxide (CO2) and storing it as carbon within soils and forest biomass. In such, forests play a critical role in mitigating the impacts of climate change now, and into the future. The Northern Research Station is working to improve the understanding of how management actions affect complex ecological processes, such as the interface between land use, management, and above- and belowground carbon uptake and storage.
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Increased carbon dioxide (CO2) in the atmosphere has been linked to climate change and is a global concern, but forests have great potential to reduce CO2 through carbon sequestration. Using data compiled from five independent, long-term silvicultural studies on Forest Service experimental forests in the northeastern and north central United States, Kern, et al. compared carbon sequestration rates in unmanaged forests with forests managed using uneven-aged management techniques that use frequent, light harvesting. The combined dataset generated from these studies provided insight into decades-long, broad trends in carbon sequestration when forests are managed using uneven-aged management. Findings demonstrated that uneven-aged management can have a positive effect on carbon sequestration at low stocking levels and where moisture and temperature are suitable. |
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Management Considerations
- Forest management, aimed at supporting vigorous tree growth and minimizing tree mortality by optimizing stand stocking levels with timely removals, can influence carbon sequestration.
- Uneven-aged management tended to have positive effects on C sequestration in certain conditions.
- Primary results suggest that, with thoughtful application in forest types where it is appropriate, uneven-aged management such as single-tree selection used here can be used to mitigate climate change while supporting commercial forestry and ecological services.
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How can forest management positively affect the U.S. carbon balance over the long run? In a new study, scientists with the University of Maine and the Northern Research Station used data about carbon stored in living trees, dead wood, and wood products from 20 northern conifer and mixedwood stands at the Penobscot Experimental Forest in Maine. They found that strategies to maintain high stocking levels and grow trees to large sizes can enhance carbon storage. Multiple entries can alter the course of stand development to mitigate emerging forest health risks, produce large trees and high value wood products, and positively impact carbon balances over the long run. These findings enable more effective management for healthy and productive forests that help to mitigate climate change. |
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Management Considerations
- Findings indicate that maintaining portions of the landscape as reserves (no harvesting) combined with multi-age silvicultural techniques can enhance carbon sequestration, compared to other management alternatives.
- Multi-age silvicultural systems (e.g., irregular shelterwood systems) can increase resilience by maintaining structural and compositional complexity.
- Human perturbation of northern forest ecosystems through management activities can not only optimize stocking so that longer lived forest products are created (larger trees producing sawtimber as opposed to pulpwood/chips) but also opportunities to increase forest resiliency (diversity in tree species, size, and structure) in the face of climate change.
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We already knew that timber harvesting impacts on soil carbon in the Lake States aren’t the same everywhere, but for the first time, we now have a clearer picture of why, and what can be done about it. In the Lake States, soils hold more than half of all forest carbon. Until now, researchers have not known how management affects the size of this resource—the largest single pool of forest carbon—at the landscape scales where many management decisions are made. Thanks to an analysis of existing data, scientists with the Northern Research Station, Northern Institute of Applied Climate Science, University of Michigan, and American Forests can now offer forest managers the information they need to incorporate soil carbon into planning, assessments, and operations. This team established that soil properties such as texture mean the difference between significant gains and significant losses of carbon when forests are harvested. Researchers also revealed how past management influences current patterns of soil carbon storage and highlighted the contribution of reforested minelands in sequestering soil carbon.
This assessment looked into how and where forestry, fires, and reforestation influence soil organic carbon across the Lake States region, and also summarized site-level tactics that may be used to mitigate probable losses or capitalize on gains in soil organic carbon, where relevant.
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Land management activities including timber harvesting, prescribed burning, and reforestation activities all have the potential to alter the stocks, cycling, and distribution of soil organic carbon in forests. Researchers with the Northern Research Station, Northern Institute of Applied Climate Science, University of Michigan, and American Forests are investigating how management actions influence soil carbon and whether management practices such as timber harvesting significantly contribute to soil carbon increases or losses.
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Management Considerations
- Natural soil factors, such as soil texture and parent material usually have stronger influence on soil organic carbon (SOC) than management impacts.
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Management impacts on SOC (positive or negative) tend to be largest at the soil surface and diminish with depth.
- Good soil management is good soil carbon management: actions taken to protect soils from physical disturbance likely mitigate negative impacts of vegetation management on SOC.
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Soils contain roughly three times more carbon than the atmosphere, and the impacts of a changing climate have the potential to turn soils from a carbon sink to a carbon source. By applying radiocarbon dating to soils from 40 NEON sites across the United States, Northern Research Station, Northern Institute of Applied Climate Science, and University of Michigan scientists were able to assess the relative importance of different climate variables and soil characteristics on soil carbon stability. |
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Management Considerations
- Moisture availability, rather than temperature alone, is a key driver of the soil carbon cycle at the continental scale.
- Soils in drier ecosystems, such as grasslands and shrublands, cycle carbon at a slower rate but store less carbon on average in comparison to wetter ecosystems such as forests. In addition, certain types of minerals associated with increased soil carbon stability are too rare in most soils to offer significant protection from climate change.
- These findings further a basic understanding of the mechanisms driving soil carbon storage and imply that climatic shifts could strongly impact how and where carbon is stored in soils.
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About Rooted in Research
Rooted in Research is a science communications platform of the Northern Research Station focused on delivering the latest science for land management needs and highlighting key science findings to people who make and influence decisions about managing land.
Forest Service Research and Development (FS R&D) works with partners to deliver the knowledge and tools that land managers need to sustain the health, diversity, and productivity of our Nation’s forests and grasslands for present and future generations. The Northern Research Station (NRS), one of seven FS R&D units, is rooted in the geography of the Northeast, Central Appalachians, and Midwest. NRS science improves lives and landscapes.
For more information, please contact
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