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Tree Bark Microbes Also Clean the Air by Removing Greenhouse and Toxic Gases
Trillions of microbes in tree bark consume methane, hydrogen, and carbon monoxide, potentially removing up to 55 million tonnes of hydrogen annually and offsetting 15% of human methane emissions.
On January 8, 2026, a Science paper led by Dr. Bob Leung of Monash and Dr. Luke Jeffrey of Southern Cross reports bark microbes consume methane and other climate-active gases.
Researchers sampled trees across eastern Australia over five years, using metagenomic sequencing and biogeochemical methods to identify microbes and their gas-consuming genes in species like paperbark and Grey Gum.
Field measurements showed a single square metre of bark can contain 6 trillion microbial cells, and the global bark surface area is about 143 million square kilometres, forming the caulosphere.
Models indicate tree-associated microbes could remove as much as 143 million tonnes of hydrogen annually and may offset up to 15% of human methane emissions, adding around 10% to climate benefits.
However, the global picture remains uncertain because the team sampled only eight tree species from eastern Australia, and Professor Vincent Gauci, University of Birmingham, plans follow-up work on deforestation impacts and enhancing tree-associated gas removal to guide reforestation and urban greening projects.