On average, one tree converts one tonne of CO2 into 1.1 m³ of wood. One cubic metre of wood therefore contains 0.9 tonnes of CO21. However, the amount of CO2 absorbed by a tree depends on many factors, including the type of tree, its age, its health and the environment in which it grows.

For an oak, which is a deciduous tree, we can estimate that it absorbs around 4.6 tonnes of CO2 per year and per hectare. 

It is also important to note that the Swiss forest absorbs around 2 tonnes of CO2 per hectare per year. This offsets almost a fifth of the CO2 emissions caused by traffic.

Finally, it should be noted that trees convert CO2 into carbon through photosynthesis and store it in the biomass4. Once the wood has been felled, the carbon can remain fixed in wooden products for a long time.

So this information should give you an idea of the importance of trees in absorbing CO2. They play a crucial role in the fight against climate change.