We all know trees are climate heroes. They pull carbon dioxide out of the air, release the oxygen we breathe, and help combat climate change.

Now, for the first time, our research has uncovered the hidden world of the tiny organisms living in the bark of trees. We discovered they are quietly helping to purify the air we breathe and remove greenhouse gases.

These microbes “eat”, or use, gases like methane and carbon monoxide for energy and survival. Most significantly, they also remove hydrogen, which has a role in super-charging climate change.

What we discovered has changed how we think about trees. Bark was long assumed to be largely biologically inert in relation to climate. But our findings show it hosts active microbial communities that influence key atmospheric gases. This means trees affect the climate in more ways than we previously realised.

Over the past five years, collaborative research between Southern Cross and Monash universities studied the bark of eight common Australian tree species. These included forest trees such as wetland paperbarks and upland eucalypts. We found the trees in these contrasting ecosystems all shared one thing in common: their bark was teeming with microscopic life.

We estimate a single square metre of bark can hold up to 6 trillion microbial cells. That’s roughly the same number of stars in about 60

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