Within each of these categories there are many different subtypes of forest. The kind of forest that can grow depends on local soils, temperatures and rainfall. For example, in southern Europe, long hot summers encourage the growth of a special kind of vegetation called the Mediterranean scrublands. Although they rarely grow thickly enough to be called a true forest, the trees in the Mediterranean scrub lands include small oaks and pines. A characteristic tree of these lands is the cork-oak, which occurs naturally but is also planted for its valuable bark.
Overgrazing by sheep and goats has changed much of the once-forested areas of the Mediterranean into scrubland known as ‘maquis’. Mediterranean scrublands are rich in wildflowers and birds, especially insect-eating birds which are abundant in summer. One of the most spectacular birds found here is the azure-winged magpie.
Some temperate forests receive so much rain they are sometimes called rainforests! The great Douglas fir and hemlock forests of the United States' Pacific Northwest and Canada's British Colombia receive more than 2,000 mm of rain a year. They are dominated by coniferous trees.
Another type of temperate, evergreen rainforest occurs in Chile, South America. Here there is a great diversity of broadleaved trees including the Southern Beech.
Broadleaved trees have big, thin-skinned leaves which allow them to absorb maximum sunlight. These leaves are delicate and vulnerable to winter winds, frost and snow. Broadleaved trees that grow in colder areas shed their leaves in winter - they are deciduous.
In autumn, the leaves turn beautiful shades of red, orange and yellow before they drop off the trees. Common deciduous trees are the oak, elm and beech. Others are maple, lime and chestnut.
In much of the northern hemisphere, most of the natural broadleaved forests have been cut down to provide farmlands. Forests survive only in small patches, or on mountains. The only large areas of forest left are the coniferous forests of northern Scandinavia, Siberia, the north western United States, Canada and Alaska. Even here, there are few areas of forest left that are in their natural state.
Temperate forests are simpler in structure than tropical forests and support a smaller number of tree species.