Tree bark removes methane from the atmosphere

Jul 24. () –

Tree bark surfaces play an important role in removing methane gas from the atmosphereaccording to a study published in ‘Nature’. Specifically, an international team of researchers led by the University of Birmingham (United Kingdom) has demonstrated for the first time that microbes living in the bark or in the wood itself remove atmospheric methane on a scale equal to or greater than that of the soil. They estimate that this newly discovered process makes trees 10 percent more beneficial to the overall climate than previously thought.

While it has long been known that trees benefit the climate by removing carbon dioxide from the atmosphere, this new research reveals a surprising additional climate benefit: microbes hidden in tree bark can absorb methane (a potent greenhouse gas) from the atmosphere. Moreover, methane is known to be responsible for about 30 percent of global warming since pre-industrial times, and emissions are now rising faster than at any time since records began in the 1980s.

So, Although most methane is removed by processes in the atmosphere, soils are full of bacteria that absorb the gas and break it down to use as energy.Soil was once thought to be the only terrestrial sink for methane, but researchers now show that trees may be just as important, if not more so.

The study’s lead researcher, Professor Vincent Gauci from the University of Birmingham, said: “The main ways we consider trees’ contribution to the environment is by absorbing carbon dioxide through photosynthesis and storing it as carbon. However, These results show a remarkable new way in which trees provide a vital climate service.

“The Global Methane Commitment, launched in 2021 at the COP26 climate change summit, aims to reduce methane emissions by 30 percent by the end of the decade. Our results suggest that planting more trees and reducing deforestation must certainly be important parts of any approach to achieving this goal.“.

In the study, the researchers looked at trees from tropical, temperate and boreal upland forests. Specifically, they took measurements in tropical forests in the Amazon and Panama; temperate broadleaf trees in Wytham Woods, Oxfordshire, UK; and boreal coniferous forests in Sweden. Methane uptake was strongest in tropical forests, probably because microbes thrive in the warm, humid conditions found there.On average, the newly discovered methane absorption adds about 10% to the climate benefit provided by temperate and tropical trees.

By studying the exchange of methane between the atmosphere and tree bark at multiple heights, they were able to show that while at ground level the trees probably emitted a small amount of methane, from a couple of meters up the direction of the exchange changes and the methane in the atmosphere is consumed.

In addition, the team used laser scanning methods to quantify the total bark area of ​​forest trees globally; preliminary calculations indicate that the total global contribution of trees is between 24.6 and 49.9 Tg (million tonnes) of methane. This fills a major gap in understanding global methane sources and sinks.

Analysis of the shapes of the trees also shows that if the bark of all the world’s trees were laid flat, the area would be equal to the surface of the Earth. “The woody surfaces of trees add a third dimension to the way life on Earth interacts with the atmosphere, and this third dimension is full of life and surprises,” said co-author Yadvinder Malhi of the University of Oxford.

Professor Gauci and his colleagues in Birmingham are planning a new research programme to find out whether deforestation has led to an increase in atmospheric methane concentrations. They also aim to better understand the microbes themselves and the mechanisms they use to absorb methane, and will investigate whether the removal of atmospheric methane by trees can be improved.