🌱 These fig trees turn CO2 into stone, a surprising discovery

Some African fig trees possess an astonishing ability. They transform carbon dioxide into stone, according to a recent study.

An international team discovered that these trees store calcium carbonate in their trunks. This process, called the oxalate-carbonate pathway, allows for capturing CO2 from the atmosphere. The researchers studied three fig tree species in Kenya, revealing unexpected mineral formations.


Fig trees use photosynthesis like all trees, but some go further. They produce calcium oxalate crystals, which are then transformed into calcium carbonate. This mineral, similar to chalk, enriches the soil with nutrients and alkalizes its environment.

Dr. Mike Rowley emphasizes the importance of this discovery. According to him, selecting trees capable of this dual storage could amplify the benefits of agroforestry. The studied fig trees, particularly Ficus wakefieldii, show remarkable efficiency in this process.

The analyses revealed the presence of calcium carbonate both on the surface and inside the wood. This discovery shows deeper sequestration than expected. Microorganisms play a key role in this transformation, opening new research perspectives.

The study paves the way for concrete applications to combat climate change. By identifying other species capable of this mechanism, scientists hope to develop more effective planting strategies. The oxalate-carbonate pathway could thus become a valuable tool.

How do fig trees turn CO2 into stone?

Fig trees absorb carbon dioxide from the atmosphere during photosynthesis. Some of this CO2 is converted into calcium oxalate, a compound found in many plants.

When parts of the tree containing these crystals decompose, microorganisms come into play. They transform calcium oxalate into calcium carbonate, a stable mineral.

This process alkalizes the surrounding soil, improving its fertility. Unlike organic carbon, calcium carbonate persists in the soil for centuries.

This unique metabolic pathway offers a natural method of carbon sequestration. It combines the ecological benefits of agroforestry with a sustainable solution to reduce greenhouse gases.