Tropical evergreen forests (or tropical rain forests) are usually found in areas receiving more than 2000 mm of rainfall and having a monthly mean temperature of 18°C or higher in the coldest months. They occupy about seven per cent the Earth's land surface and harbour more than half of the planet's terrestrial plants and animals.Tropical evergreen forests are dense, multi-layered, and harbour many types of plants and animals. The trees are evergreen as there is no period of drought or frost. The canopy tree species are mostly tall hardwoods with broad leaves that release large quantities of water through transpiration, in a cycle that is important in raising as much mineral nutrient material as possible from the soil.They do not shed their leaves at a time and therefore always remain green and are called evergreen forest.Here the trees are 60 m in height and the rainfall is between 15 cm to 30 cm.
Temperate evergreen forests, coniferous, broad leaf, and mixed, are found largely in the temperate mid-latitudes of North America, Siberia, Canada, Australia, Africa and Scandinavia. Broadleaf evergreen forests occur in particular in southern China, southeastern Brazil, parts of southeastern North America, and in countries around the Mediterranean Basin, such as Lebanon and Morocco. Other examples include the wet temperate conifer forests of northwestern North America.
Coniferous temperate evergreen forests are most frequently dominated by species in the families Pinaceae and Cupressaceae. Broadleaf temperate evergreen forests include those in which Fagaceae such as oaks are common, those in which Nothofagaceae predominate, and the Eucalyptus forests of the Southern Hemisphere. There also are assorted temperate evergreen forests dominated by other families of trees, such as Lauraceae in laurel forest.
Evergreen forests around the world are under threat of logging, mining, oil and gas developments, pollution, hydroelectric projects and other human developments planned in these areas.
See also
- Deciduous forest
- Biomes
- Ecoregion
- Ecological land classification
- List of terrestrial ecoregions (WWF)
- *Temperate coniferous forest
External links
- Tropical Evergreen Forests