There are 60,065 species of trees in the world, according to a comprehensive study of the world's plants.
Botanical Gardens Conservation International (BGCI) compiled the tree list by using data gathered from its network of 500 member organisations.
It hopes the list will be used as a tool to identify rare and threatened species in need of immediate action to prevent them becoming extinct.
Details of the study appear in the Journal of Sustainable Forestry.
The data revealed that Brazil was the nation with the greatest number of tree species, home to 8,715 varieties.
Apart from the polar regions, which have no trees, the near-Arctic region of North America had the fewest number of species, with less than 1,400.
Another fact to emerge from the data was that more than half of the species (58%) were only found in one country, suggesting that they were vulnerable to potential threats, such as deforestation from extreme weather events or human activity.
About 300 species have been identified as critically endangered as they had fewer than 50 individuals remaining in the wild.