There are more than 3 trillion trees on earth, that means there are about 422 trees per person. However, the total number of trees has almost been halved since the start of human civilization. Ecosystems with a long lifespan, like forests, are more vulnerable to the relatively quick changes of climate change.
Forests have numerous important functions (so-called ecosystem services): via photosynthesis they produce oxygen and biomass, retain fresh water, serve as home for lots of animal species and humans, influence weather patterns and fix carbon dioxide. By managing forests in a sustainable way these functions can be fulfilled by forests in the future as well and can help to prevent and deal with climate change.
European forests are growing old, which means they will convert less carbon from the atmosphere into biomass. Nevertheless, European forests still sequester about 362 million tonnes of CO2 annually.