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TREETHANE

Posted on 2026/01/28 by secret santa

“Tree bark is populated with microbes that consume important climate gases, including methane, hydrogen and carbon monoxide” credit Luke Jeffrey

METHANOTROPHIC BARK MICROBIOME
https://theconversation.com/methane-eating-bacteria-living-in-trees
https://theconversation.com/microbes-in-bark-eat-climate-gases
https://phys.org/news/2026-01-tree-bark-microbes-air-greenhouse.html
Tree bark microbes also clean air by removing greenhouse & toxic gases
by Monash University / January 8, 2026

“Australian researchers have discovered a hidden climate superpower of trees. Their bark harbors trillions of microbes that help scrub the air of greenhouse and toxic gases. It’s long been known that trees fight global warming by consuming carbon dioxide (CO₂) through photosynthesis. But a new study published in Science shows their microbial partners take up vast amounts of other climate-active gases too.

“Paperbark forest in a wetland, where bark-dwelling
methane-eating microbes were discovered.” credit Luke Jeffrey

The study, titled “Bark microbiota modulate climate-active gas fluxes in Australian forests,” conducted primarily by Dr. Bob Leung at Monash University’s Biomedicine Discovery Institute (BDI), and Dr. Luke Jeffrey at Southern Cross University’s Faculty of Science and Engineering, rewrites our understanding of how trees and their resident microbes shape the atmosphere. “Each tree hosts trillions of microbial cells on its bark,” said Dr. Leung, a co-first author. “Yet their existence and roles have been overlooked for many decades until now.”

Melaleuca quinquenervia

The researchers spent five years sampling trees across eastern Australia, including wetland, upland, and mangrove forests. They then used advanced genomic and biogeochemical techniques to determine, for the first time, the identities, capabilities and activities of the microbes living in their bark. “Remarkably, most of these microbes are tree-adapted specialists that feed on climate-active gases,” Dr. Leung said. “They consume methane, hydrogen, carbon monoxide, and even volatile compounds released by the trees themselves.”

Dr. Jeffrey, also a co-first author, said the scale of this hidden process was staggering. “Counting all trees on Earth, the total global surface area of bark covers an area roughly the same as all seven continents combined,” he said. “This microbial activity across this massive ‘bark continent’ is potentially removing millions of tons of climate-active gases every year. “These gases can come from the atmosphere or from within tree stems. By consuming these unwanted gases, microbes in bark are essentially cleansing our air and enhancing the benefits of trees in multiple ways.”

The BDI’s Professor Chris Greening, who co-led the study with Southern Cross University’s Professor Damien Maher, said there was much long-term potential to use these findings for climate action. “We now know different trees host different microbes,” Professor Greening said. “If we can identify the trees with the most active gas-consuming microbes, they could become priority targets for reforestation and urban greening projects.” Professor Greening added that the discovery could benefit both climate and human health. “In addition to being a climate-active gas, carbon monoxide is also a toxic air pollutant,” he said. “Tree microbes are helping scrub it from the air and so improve air quality.” Professor Maher said there were many more discoveries to be made in this research area. ”

This research is really the tip of the iceberg in terms of expanding our understanding of how trees and microbes interact,” he said. “The diversity of microbes that we found living in the bark of these trees suggests that we may need to rethink how trees and forests control Earth’s climate now and into the future.” The tree species included paperbark (Melaleuca quinquenervia), Swamp box (Lophostemon suaveolens) and Swamp oak (Casuarina glauca) from freshwater wetland forest; Banksia (Banksia integrifolia) and Golden wattle (Acacia longifolia) from coastal heath forest; Mangrove (Avicennia marina) from mangrove forest; Grey ironbark (Eucalyptus siderophloia) and Grey Gum (Eucalyptus propinqua) from upland forest.”

References
–Pok Man Leung et al, Bark microbiota modulate climate-active gas fluxes in Australian forests, Science (2026). DOI: 10.1126/science.adu2182
–Vincent Gauci, Tree bark microbes for climate management, Science (2026). DOI: 10.1126/science.aec9651

TREE METHANE EXCHANGE
https://nature.com/articles/s43017-025-00692-9
https://news.mongabay.com/australian-tree-bark-microbes
https://the-scientist.com/microbes-in-tree-bark-cycle-greenhouse-gases
Microbes in Tree Bark Cycle Greenhouse Gases
by Sneha Khedkar / Jan 8, 2026

“The cracked, hard bark of woody plants carries more than just lichen, insects, and years of dust. The seemingly barren layer teems with trillions of microbes, including bacteria, algae, and fungi.¹ Tree bark across the planet spans a surface area roughly similar to that of all terrestrial land, placing these bark-associated microbes all across the globe. Despite this, scientists do not fully understand the metabolism of these microbes and the roles they play in the ecosystem.

Now, researchers led by Monash University microbiologists Pok Man Leung and Chris Greening and Southern Cross University biogeochemist Luke Jeffrey used metagenomics to characterize the bark microbiota of eight common Australian tree species.² They found that bark microbes can cycle the greenhouse gases methane, hydrogen, and carbon monoxide. The results, published in Science, suggest that bark microbiota likely contribute to the climate benefits of trees by regulating gas cycling.

Leung, Jeffrey, Greening, and their team first measured gas concentrations within the bark of one tree species. They observed increased abundance of hydrogen, carbon monoxide, and methane in the stem compared to the atmosphere. They also examined volatile organic compounds (VOCs) in the bark and observed high concentrations of methanol, acetaldehyde, butene, and other compounds commonly produced by microbial communities. Consistent with this, quantitative polymerase chain reaction using DNA isolated from tree trunks revealed the presence of more than six trillion bacteria per square meter of bark. Sampling seven additional common tree species indicated similar abundance of microbes in the trunk.

To profile the composition and metabolic functions of microbes in this community, the researchers carried out metagenomic sequencing. Metagenomic analyses indicated that the microbes encoded several enzymes that would help them metabolize the high concentrations of gases and VOCs in tree bark. They noticed that bark microbes exhibited a wide variety of enzymes to break down hydrogen gas. This suggested that the microbes could metabolize gases under variable environmental conditions. This could include periods of oxygen abundance—such as during the day—as well as oxygen scarcity—such as such as in water-saturated conditions or at night.

“Measuring paperbark tree stem gases using a stem gas flux
chamber in a freshwater wetland. credit Luke Jeffrey”

To test this hypothesis, the researchers placed strips of tree bark into bottles and flushed them with air either containing or lacking oxygen. They analyzed the flux of gases in each case and observed that bark microbes consumed hydrogen, carbon monoxide, and methane under oxic conditions. During anoxic conditions, the bark microbes produced these gases, indicating that tree trunks are biogeochemical hotspots for climate-active gas cycling. “Collectively, these results suggest that trees and their microbiota contribute to regulating global atmospheric cycles and should be considered in biogeochemical models, forest management, and conservation efforts,” the authors wrote in the paper.

“The research team taking field measurements and collecting
bark samples in tropical forests near Darwin.” Credit Luke Jeffrey

They further noted that these properties should be considered in forest management to optimize plantation of tree species that could remove greenhouse gases under local conditions. “Future work should extend these findings by examining the role of trees as sources and sinks of trace gases beyond the few species and narrow geographic location of this study,” wrote Vincent Gauci, a University of Birmingham biogeochemist who was not associated with the study, in a related perspective article.”³

References
-Arnold W, et al. A diverse and distinct microbiome inside living trees. Nature. 2025;644(8078):1039-1048.
-Leung PM, et al. Bark microbiota modulate climate-active gas fluxes in Australian forests. Science. 2025.
-Gauci, V. Tree bark microbes for climate management. Science. 2025.

BARK DWELLERS
https://nature.com/articles/s41579-026-01281-3
https://nature.com/articles/s41467-021-22333-7
https://sciencenews.org/article/tree-bark-microbes-climate-gases
by Douglas Fox / January 8, 2026

“Trees are known for capturing carbon dioxide as they grow. But they also soak up other gases implicated in climate change through microbes in their bark. The tree bark microbes feast on hydrogen, methane and carbon monoxide, researchers report January 8 in Science. Methane is a greenhouse gas 28 times more potent than carbon dioxide over a 100-year period. Carbon monoxide — which is lethal to humans — and hydrogen enhance global warming indirectly, by helping methane persist longer in the atmosphere. Getting rid of these gases “is a hidden benefit of trees that we previously didn’t realize was happening,” says Luke Jeffrey, a biogeochemist at Southern Cross University in Lismore, Australia.

An estimated 41 million square kilometers of tree bark exist worldwide — about equal to the combined area of North and South America, and about six trillion microbes inhabit every square meter of tree bark, Jeffrey and his colleagues estimate. This newly discovered bark microbiome was “hidden in plain sight,” says Jonathan Gewirtzman, a forest ecologist at Yale University, who was not part of the project. It “highlights this as an environment that we know so little about.” These discoveries about the hidden tree bark biome stem from years of research into the sources of methane, which is responsible for about 30 percent of human-caused warming. This gas bubbles up from oxygen-starved microbes living in the waterlogged sediments of lakes and wetlands.

“Trees act as conduits linking soils and the atmosphere, facilitating gas exchange and as a niche for microbial communities adapted to metabolizing gas substrates. Together, trees and bark microbiota function as a modulator of the emission and uptake of multiple climate-active gases in forest ecosystems.”

When scientists measured methane percolating up from the flooded lowlands of the Amazon, the amount coming out was only about half what it should be, based on measurements from space. Then in 2017, another team of scientists realized that only half of region’s methane was coming out of the ground. The other half — amounting to 15 or 20 million metric tons per year — was seeping out of Amazonian tree trunks. People thought the trees were acting as passive chimneys — gushing out soil methane that came in through their roots. But in 2021, Jeffrey and his colleagues discovered a wrinkle.

Working with broad-leaf paper bark trees (Melaleuca quinquenervia) in Australia, the team found that the amount of methane coming out of tree bark was about 35 percent less than what enters from below. They concluded that microbes in the bark were eating it — oxidizing it for energy – as it seeped out. “That could be a really huge ecosystem service that these microbes are providing” by removing a major greenhouse gas, says Pok Man Leung, an ecophysiologist at Monash University in Clayton, Australia. He and Chris Greening, a microbiologist also at Monash, helped identify the microbes living in the bark of those trees.

In the latest study, Jeffrey, Leung, Greening and colleagues profiled the collective genomes of thousands of microbial species living in paper bark trees and seven other common tree species in Australia. The researchers found that microbes that oxidize hydrogen gas for energy were even more common than the methane-eaters. Microbes that oxidize carbon monoxide were also abundant. Experiments in live trees showed that bark microbes don’t just eat these gases as they diffuse up through the trees; they also suck in methane, hydrogen, and carbon monoxide from the surrounding air. These gases exist in the atmosphere at only trace levels, ranging from 2 parts per million to 40 parts per billion. But multiplied across the entire world, tree microbes are consuming vast amounts of them – an estimated 25 to 50 million tons of methane alone, according to a 2024 study.

By removing these other climate gases, tree bark microbes enhance the already significant benefits trees provide by absorbing CO₂, Leung says. Forest restoration remains an important strategy for combating climate change, and this new knowledge could make it more effective. The eight tree species examined in this study had differing mixes of microbes in their bark, eating different amounts of trace gases. This insight could help scientists select the tree species best suited to blunt climate change. “You’re not just thinking about the tree you’re planting, but also the microbes within the tree,” Greening says. “You can ideally get rid of three or four climate-active gases for the price of one.”

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