Rainforest

A rainforest is a forested biome with high annual rainfall due to the Intertropical convergence zone. Some cite a minimum normal annual rainfall of 2000 mm (about 100 inches or 200 centimetres), with normal rainfall at least 60 mm during each of the twelve months of the year. Others set the minimum annual rainfall barrier as low as 1700 mm (about 67 inches). The soil can be poor because high rainfall tends to leach out soluble nutrients. This type of biome is found in both temperate and tropical climates. As well as prodigious rainfall, many rainforests are characterised by a high number of resident species and tremendous biodiversity.

Related Topics:
Forest - Biome - Rain - Intertropical convergence zone - Nutrient - Temperate - Tropical - Climate - Resident - Species - Biodiversity

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Rain forests are home to two-thirds of all the living animal and plant species on the planet. It has been estimated that many hundreds of millions of new species of plants, insects, and microorganisms are still undiscovered and have no names yet. Tropical rain forests are called the "jewel of the earth", the "Earth's lungs", and the "world's largest pharmacy" because of the large amount of natural medicines discovered there.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

Despite the growth of flora in a rainforest, the actual quality of the soil is quite poor. Oxisols, infertile, deeply weathered and severely leached, have developed on the ancient Gondwanan shields. Rapid bacterial decay prevents the accumulation of humus. The concentration of iron and aluminium oxides by the laterization process gives the oxisols a bright red color and sometimes produces minable deposits (e.g. bauxite). On younger substrates, especially of volcanic origin, tropical soils may be quite fertile.

Related Topics:
Oxisols - Gondwana - Shields - Humus - Iron - Aluminium - Bauxite

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

The undergrowth in a rainforest is restricted in many areas by the lack of sunlight at ground level. This makes it possible for people and other animals to walk through the forest. If the leaf canopy is destroyed or thinned for any reason, the ground beneath is soon colonised by a dense tangled growth of vines, shrubs and small trees called jungle.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

In the Köppen climate classification system, they are designated as (Af).

~ ~ ~ ~ ~ ~ ~ ~ ~ ~