Monday, February 25, 2013

Vegetation comprises of plants growing over the surface of the earth. The plant geographers have divided the vegetation of the world into four great biochores :

The Forest Biochore : Defined as plant formation consisting of trees growing close together  nd forming a layer of foliage that shades the ground.

The Savanna Biochore : It is a combination of trees and grasslands.

The Grassland Biochore : An upland vegetation of herbs which include grasses or grasslike plants and herbs.

The Desert Biochore : It is associated with arid climate and thinly dispersed plants. 

According to varied climate and density of vegetation cover, the vegetation of world is divided into three types.

1. Forests Forests are classified on the basis of coverage, density and greenery.

(a) Tropical Rainforests : These are known as equatorial forests and found in Amazon Basin, Zaire Basin and other wetter areas  in the monsoon regions. These are broad-leaved hardwoods composed of trees like Mahogany, Rubber, Cinchona, etc.

(b) Monsoon Forests : These are found in areas having 100 to 200 cm of rainfall. They are hardwood forests and generally deciduous.
(c) Coniferous Forests : These are evergreen, needlelike softwood forests found in North America and South America.

2. Grasslands
Grasslands are characterized by less rainfall.
(a) Savannas : These are tropical grasslands, occuring as a transitional belt between  hot desert and monsoon regions and are areas of thick high grasses. These are known by different names like Parkland in Africa, Illonos in Venezuela, Campos in Brazil and Downs in Australia.

(b) Steppes : These are short, shallow rooted grasses growing in bunches. These are found in low latitudes and middle latitudes. These are reduced to weedy plants due to overgrazing.

(c) Prairies : These are temperate grasslands. The grasses are tall and deep rooted. These are found in Southern Russia, Central Europe and Argentina. The original vegetation in these regions is destroyed and the land turned into agricultural land.

(d) Meadows : These are grasslands maintained artificially and known as pastures; common in England and North Kalahari desert.

3. Desert Shrubs Desert shrubs consist of bushy plants in hot sandy deserts and mosses in cold tundras. These occur in parts of Atacama desert in South America.


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