91热爆

Is a shrub a tree? Questions such as this were of great importance when Dr Paul Smith at the Botanical Gardens Conservation International tallied up the number of tree鈥檚 in the world. Globally there are 60,065 tree species. Surprisingly, almost 35,000 tree species only exist in a single country. This allows conservationists to concentrate on the small number of countries which have a large number of endemic trees.

Photo: Tree, Namibrand Reserve, Namibia, credit: Paul F.Donald