How important trees are to life is well known: they provide oxygen through chlorophyll photosynthesis, they provide the habitat for half of the world’s known terrestrial animal and plant species, and they are essential for carbon storage in many ecosystems such as woodland, forests and grasslands, as well as in man-made and urban environments. Despite the fact that they play a key role on our planet, until now there have been many gaps in knowledge about the diversity, distribution and conservation status of trees on a global scale.
Extensive research has been undertaken over the past five years to close this information gap and collect data on the extinction risk of the 58,497 species of trees worldwide. The result of this research is the State of the World’s Trees, a new report published by Botanic Gardens Conservation International (BGCI), an organisation that collects and publicises documentation on the plants of our planet. The report shows that 30% of tree species are threatened with extinction, 142 species of trees have already become extinct and 442 are threatened to the point where there are fewer than 50 specimens remaining in the world. Just as for animal species, the most important threats are deforestation, destruction of habitats to convert land to cropland, livestock farming, urban development, fires and climate change.
Documenting the conservation status of nearly sixty thousand tree species is the largest task ever undertaken in the history of the IUCN Red List, the largest database on the conservation status of animal and plant species worldwide, maintained by the International Union for Conservation of Nature. “For the first time we now know which of these species are in need of conservation action, what are the greatest threats to them and where they are,” Malin Rivers of the BGCI explained to the BBC.
The report not only presents a comprehensive analysis of the species found on Earth, but also offers a way forward to ensure their survival. According to experts, protected areas need to be expanded, since at the moment at least 64% of all tree species are found precisely in these areas. It would also be important to keep specimens of the most endangered species in botanical gardens and preserve their seeds in the seed bank, a place where the seeds of 30% of the world’s trees are kept in the hope of one day replanting them in the wild. Lastly, the researchers stress the importance of publication of scientific information to ensure the success of reforestation and conservation action, as well as the need to start from the bottom and involve local citizens, as well as institutions.