Can smarter forest buffer strips along streams help to mitigate climate change?
Forests are important components of the global climate system, taking up large amounts of carbon. Yet, part of this carbon is lost to inland waters and emitted back to the atmosphere as greenhouse gases. Recent research indicates the importance of forest management along streams for such emissions. Supported by new research funding, Marcus Klaus is now seeking to understand how forestry related greenhouse gas emissions can be reduced by new ways to design forest buffer strips along streams.
Text: Ingrid Söderbergh
Marcus Klaus measuring carbon dioxide emissions from a forest stream.
Mitigating climate change is one of the biggest challenges to humanity. Forestry plays an important role in climate change mitigation, because forests are efficient at binding carbon from the atmosphere and counteract human-made greenhouse gas emissions. However, forest clear-cutting can also lead to enhanced greenhouse gas emissions, and a major question is how forest management can be optimized to minimize these emissions.
To reduce forestry impacts on inland waters, forest strips, so called riparian buffer zones, are typically left along the shoreline. Inland waters can emit large amounts of GHGs previously fixed in forests. New research now shows that the layout of these buffer zones can be important for reducing forestry effects on greenhouse gas emissions from inland waters.
"First, we were puzzled about the fact that inland waters did not emit more greenhouse gases after forest clear-cutting despite enhanced greenhouse gas concentrations in groundwaters. Later, however, we realized that this could be due to uptake or emissions in the riparian buffer zone", says Marcus Klaus, Postdoc at the Department of Ecology and Environmental Science at Umeå University and first author of two recent research papers on the topic.
The two studies, based on field experiments and analyses of national environmental monitoring data, lead to exciting new questions: If not inland waters, is it the riparian buffer zones that emit the greenhouse gases accumulated in groundwater after forest clear-cutting? Can these emissions be reduced by smarter riparian buffer zone designs?
The Swedish Forest Society Foundation has now provided a grant to Marcus Klaus to carry out new field experiments together with his collaborators to study greenhouse gas dynamics in riparian buffer zones before and after experimental clear-cutting.
"We are going to measure greenhouse gas fluxes in groundwater, soils and even in tree trunks, which can serve as a pathway for greenhouse gases in the groundwater to reach the atmosphere", says Marcus Klaus.
The new study aims to provide a more holistic view on greenhouse gas fluxes in forest ecosystems that also includes inland waters, and by that hopefully contributes with important knowledge towards a long-term goal of more sustainable forest management.
"Forest management has a large responsibility for maximizing the ability of natural ecosystems to take up carbon from the atmosphere and we think that today's forestry practices have a large potential for improvements", says Marcus Klaus.
Klaus, M., Geibrink, E., Jonsson, A., Bergström, A.-K., Bastviken, D., Laudon, H., Klaminder, J. and Karlsson, J. (2018): Greenhouse gas emissions from boreal inland waters unchanged after forest harvesting. Biogeosciences 15:5575-5594. https://doi.org/10.5194/bg-15-5575-2018 Klaus, M., Seekell, D., Lidberg, W. and Karlsson, J. (2019): Evaluations of climate and land management effects on lake carbon cycling need to account for temporal variability in CO2 concentrations. Global Biogeochemical Cycles 33. https://doi.org/10.1029/2018GB005979