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An evergreen forest is a forest consisting entirely or mainly of evergreen trees that retain green foliage all year round. Such forests may be broadleaved evergreen forests, such as Moist forest that occur in tropical climates or coniferous evergreen forests such as those found in temperate and boreal climates. Some subtropical or warm temperate areas may contain laurel forest, which are broadleaved evergreen, while isolated areas of evergreen forests may occur in montane forests, and cloud forests.
The Tropical evergreen forests
Tropical evergreen forests or (tropical rain forests) are usually found in areas receiving more than 200 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.
In India, evergreen forests are found on the eastern and western slopes of the Western Ghats in such states as Tamil Nadu, Karnataka, Kerala and Maharashtra. And also found in Assam, Arunachal Pradesh, Meghalaya, Nagaland, Tripura, West Bengal and Andaman and Nicobar Islands. They are also found in the hills of Jaintia and Khasi. Some of the trees found in Indian tropical forests are rosewood, mahogany and ebony. Bamboo and reeds are also common. Because of dense foliage competing for light, little direct sunlight reaches the under story.
Temperate evergreen forests, coniferous, broadleaf, 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.
- Deciduous forest
- Ecological land classification
- List of terrestrial ecoregions (WWF)