Researchers from the State of the World's Trees project have announced: more than 17,000 tree species, i.e. one third of all known species, are threatened with extinction. In an article published in the journal Plants, People, Planet, the research group writes that today we have already lost more than 100 species and that around 15.3 billion trees are cut down every year. The main threat to the Earth's trees is habitat loss due to agriculture, which affects 29% of species, followed by deforestation (27%), animal husbandry (14%) and urban development (13%). Trees in forests are of enormous ecological importance because they provide food and shelter for a large number of other plants, animals, fungi and micro-organisms. Many trees are important for the economy because they provide raw materials and food for humans. Moreover, by storing carbon in the form of organic matter, trees are our main ally in combating climate change.