How many species of trees in the world

[Henk Beentje]

BLANC wrote:
> 
> I am often asked about the number of species of trees in the world.
> 
> Who knows wherer I can find this information ?
> 
> Thank a lot

Going from 250,000 plant species altogether (fairly conservative 
estimate), and extrapolating from 10 percent trees in some floras, you 
get 25,000 tree species in the world.
Caution: a lot depends on what you call a tree, and the boundary between 
shrub and tree depends on who you're talking to. 
Another caution: my percentage might be way off. It's based on East 
Africa, and might not be valid elsewhere. 
I'd be interested in other opinions!

Henk