News  |  11.02.2022

9,200 tree species still unknown on Earth

An international study published in the American scientific journal PNAS (Proceedings of the National Academy of Sciences) questions the number of tree species on the planet.

Although it is impossible to count the exact number of tree species on Earth, an international team of 150 researchers has formulated a new hypothesis in this study. The Earth would be home to about 73,000 species, of which 9,200 are yet to be discovered. And tropical forests would play a big role in these future undiscovered species ... The vast majority would indeed be located in tropical and subtropical rainforests. South America alone is home to 40% of these unknown species.

To develop this hypothesis, the researchers first combined the two main existing global databases, namely Global Forest Biodiversity and TreeChange, to obtain information on both the abundance of species and their occurrence. The new database obtained from this cross-referencing includes more than 38 million trees in 100 territories and 90 countries, including 64,100 known species, which is consistent with previous estimates. This gave the researchers a good overview of species diversity for different biomes and at the continental level. An equation was then developed to estimate the number of undiscovered species. For the record, the methodology used is derived from the method developed by the computer scientist Alan Turing during the Second World War to decipher the Nazi codes!

In addition, the study notes that nearly a third of these unknown species could be rare, and emphasizes that the richer and more diverse a forest is, the more resistant and resilient it is. It thus reminds us of the importance of inventory work and data collection in the field, which requires human and financial resources that should not be neglected.

Beyond the scientific interest of this study, this finding highlights the need to develop field research and to diversify the use of exploitable timber species, while ensuring sustainable management of tropical forests, respecting the rhythm of the ecosystems.

Download the study