Research that was published in "Nature" claims that the surfaces of trees have a significant effect in absorbing methane gas from the environment. Although the removal of carbon dioxide from the atmosphere by trees has long been known to improve climate, new research reveals an unexpected extra benefit. Methane is a potent greenhouse gas that can be absorbed from the environment by microbes concealed in tree bark.

For the first time, an international team of scientists headed by the University of Birmingham has demonstrated that bacteria that reside in the bark or the wood itself are eliminating atmospheric methane at a rate that is comparable to or greater than that of soil. They estimate that trees are now 10% more beneficial to the climate overall than previously believed due to this recently found process. Since pre-industrial times, methane has accounted for around 30% of global warming, and emissions are rising faster than they have ever done since statistics were kept in the 1980s. Soils are full of bacteria that absorb methane and break it down for use as energy, even though the majority of the gas is eliminated by processes in the atmosphere. Previously believed to be the only terrestrial sink for methane, research now suggests that trees may be just as significant, if not more so.

Lead researcher on the study ~ What They Have To State?

Professor Vincent Gauci of the University of Birmingham, said: "The main ways in which we consider the contribution of trees to the environment is through absorbing carbon dioxide through photosynthesis and storing it as carbon. These results, however, show a remarkable new way in which trees provide a vital climate service. "The Global Methane Pledge, launched in 2021 at the COP26 climate change summit aims to cut methane emissions by 30 percent by the end of the decade. Our results suggest that planting more trees, and reducing deforestation surely must be important parts of any approach towards this goal." In the study, the researchers investigated upland tropical, temperate, and boreal forest trees. Specifically, they took measurements spanning tropical forests in the Amazon and Panama; temperate broadleaf trees in Wytham Woods, in Oxfordshire, UK; and boreal coniferous forest in Sweden. The methane absorption was strongest in the tropical forests, probably because microbes thrive in the warm wet conditions found there. On average the newly discovered methane absorption adds around 10% to the climate benefit that temperate and tropical trees provide. By studying methane exchange between the atmosphere and the tree bark at multiple heights, they were able to show that while at soil level the trees were likely to emit a small amount of methane, from a couple of meters up the direction of exchange switches and methane from the atmosphere is consumed.


(Source: Google Images) 

Furthermore, the researchers employed laser scanning techniques to measure the total surface area of forest tree bark worldwide. Initial computations suggest that trees contribute a total of 24.6-49.9 Tg (millions of tonnes) of methane annually. This closes a significant knowledge gap about the sources and sinks of methane worldwide. The research on tree shapes also reveals that the area would be the same as the surface area of the Earth if all of the bark on all trees were laid flat. Professor Gauci and colleagues at Birmingham are currently organizing a new study project to investigate if higher atmospheric methane concentrations are a result of deforestation. Additionally, they hope to learn more about the microorganisms themselves, the processes by which they absorb methane, and whether there is any way to improve the way that trees remove methane from the atmosphere.

“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 with surprises,” said co-author Yadvinder Malhi of the University of Oxford.