A new study involved more than 100 scientists from across the world. They have assembled 73,000 tree species on Earth and about 9,200 species yet to be discovered.
The global estimate is 14% higher than the current number of known tree species. Most of the undiscovered species are rare.
The undiscovered species are vulnerable to human-caused disruptions such as deforestation and climate change. The new study will help prioritize forest conservation efforts. The research paper has been published in Proceedings of the National Academy of Sciences.
Scientists combined tree abundance and occurrence data from two global datasets. One from the Global Forest Biodiversity Initiative and another from TREECHANGE. The combined databases yielded a total of 64,100 documented tree species worldwide.
Scientists used novel statistical methods to estimate the total number of unique tree species at biome and global scales. It includes species yet to be discovered and described by scientists. Biome is a major ecological community type like a tropical rainforest.
Their conservative estimate of the total number of tree species on Earth is 73,274. This means there are about 9,200 tree species yet to be discovered. The new study used more extensive dataset and more advanced statistical methods. Scientists used modern developments of techniques.
40% of the undiscovered tree species are likely to be in South America. This is mentioned repeatedly in the study as being of special significance for global tree diversity.
South America is also the continent with the highest estimated number of rare tree species and the highest estimated percentage of continentally endemic tree species.
Hot spots of undiscovered South American tree species likely include the tropical and subtropical moist forests of the Amazon basin. Andean forests at elevations between 1,000 meters and 3,500 meters.
Half to two-thirds of all already known tree species occur in tropical and subtropical moist forests. These are both species-rich and poorly studied by scientists. Tropical and subtropical dry forests hold high numbers of undiscovered tree species.
