Based on the latest global ground-sourced data, scientists estimate that there are ∼73,000 tree species globally, among which ∼9,000 tree species are yet to be discovered.
Roughly 40% of undiscovered tree species are in South America.
Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains).
These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness.