The main forest regions of the world today are split between tropical, broad-leaved and coniferous. tropical forests are millions of years old and contain up to 86 species of tree per acre. Each tree can support up to 400 species of. They contain at least 50% of all species on earth. 90% of all primates are found in rainforests, all this in forests that cover only 10% of the earth's land surface. 20% of all bird species are in the Amazon, a single tree in Peru was discovered to be host to 43 different kinds of ant!

Clearing and logging in tropical forest is so extensive 10% of the world's species are on the verge of extinction. In comparison broad-leaved forests contain only about 4 tree species per acre. These are the types of woodlands found in the UK.

They are also under threat as urban development continues and trees are felled to make way for motorways, airport runways and other developments. 300 different species rely on the oak tree for survival.

In many northern regions such as Scandinavia there are single species conifer plantations these grow rapidly and provide timber for planks and the paper industry. Most are well managed forests. Temperate regions have planted many of these monoculture plantations, however they support few species of animals and birds and constitute a monoculture cash crop. Recently more mixed forests are being planted as the impacts of single species woodlands and the lack of their biodiversity have become apparent.