12.08.2025Fig trees convert atmospheric CO₂ to stone

Some fig trees can convert surprisingly large amounts of carbon dioxide into calcium carbonate, ensuring that the carbon remains in the soil long after the tree has died. This means that fig trees planted for forestry or their fruit could offer additional climate benefits through this carbon-sequestration process.

Fig Tree in Africa (Image Credit: Mike Rowley)

Mike Rowley, biogeochemist at GIUZ, together with a team of researchers from UZH, the Nairobi Technical University of Kenya, Sadhana Forest, Lawrence Berkeley National Laboratory, University of California, Davis, and the University of Neuchatel studied three species of fig tree grown in Samburu County, Kenya. The results were presented at the Goldschmidt Conference in Prague in July and were reported by diverse media.

”The calcium carbonate is formed both on the surface of the tree and within the wood structures, likely as microorganisms decompose crystals on the surface and also, penetrate deeper into the tree. It shows that inorganic carbon is being sequestered more deeply within the wood than we previously realized”, explains Mike Rowley.

“We believe there are many more species of tree which can form calcium carbonate,” says Rowley. “This means the oxalate-carbonate pathway could be a significant, underexplored opportunity to help mitigate CO₂ emissions.”

Literature

Biomineralising trees turn CO2 into CaCO3? Identifying novel oxalate-carbonate pathways associated with East African Fig trees in Samburu County, Kenya.
https://conf.goldschmidt.info/goldschmidt/2025/meetingapp.cgi/Paper/26094