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In a surprising discovery, researchers at the University of Birmingham have found that tree bark plays a significant role in removing methane from the atmosphere. This revelation suggests that we may have been underestimating the potential of trees to mitigate climate change.

The study, led by Professor Vincent Gauci and published in the journal Nature, revealed that microbes living inside the bark of trees absorb methane as effectively as those in the soil. Traditionally, it was believed that soil was the only effective terrestrial methane sink, as certain microorganisms use methane as a food source. However, this research shows that similar microbes reside under a tree’s bark, enabling trees not only to withdraw CO2 from the atmosphere and store it in their roots but also to remove methane efficiently.

It's All About Methane

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Methane, a potent greenhouse gas, contributes significantly to global warming, despite its relatively short lifespan in the atmosphere. The study in question looked at trees found in upland tropical forests in the Amazon and Panama, temperate broadleaf trees in the UK, and boreal coniferous forests in Sweden. Methane absorption was strongest in tropical forests due to the warm, wet conditions that favor microbial activity.

By studying methane exchange between the atmosphere and tree bark at multiple heights, researchers demonstrated that while trees might emit a small amount of methane at soil level, they consume methane from the atmosphere from a couple of meters up. Additionally, laser scanning methods were used to quantify the global forest tree bark surface area, with preliminary calculations indicating that trees contribute between 24.6-49.9 million tonnes of methane absorption globally. This finding fills a significant gap in understanding the global sources and sinks of methane.

The Third Dimension

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Co-author Yadvinder Malhi of the University of Oxford highlighted the importance of this discovery, noting:

Tree woody surfaces add a third dimension to the way life on Earth interacts with the atmosphere, and this third dimension is teeming with life and surprises.

This study underscores the critical role that trees play in regulating the climate and suggests that efforts to plant more trees and reduce deforestation could be essential components in mitigating climate change.