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Feature: Natural regions of the Earth
The surface of the Earth is divided into twelve natural regions. These regions have been categorized on the basis of surface features, climate and vegetation.
Polar regions
Polar regions are permanently ice-clad and possess hardly any vegetation and very little animal life.
Tundra region
Between the great coniferous forest of North America and Eurasia, and the polar lands of permanent ice and snow to the North lies the Tundra. Soil is frozen for most of the year and summers are brief.
Moorland
The Sub-soil is not frozen except in winter. The surface is generally rocky and the main vegetation is short shrubs and tufted grass.
Coniferous forests
These forests experience very low temperatures with little rainfall. A broad belt of needle-leaned evergreen trees cover the higher latitudes of the northern hemisphere. Winters are long and severe, the ground being frozen for most of the time.
Deciduous forests
The main areas of the world that were naturally covered by deciduous forests are North-east USA, Central Japan, North China and West Europe excluding high mountains.
Temperate grasslands (steppes)
Fairly wet, these are those parts of the world which usually have hot summers, cold winters and moderate rain fall. These areas at one time were covered by grass, almost six feet high at some places. Because of many changes wrought by man and animals, little of the original grass remains. These lands have emerged as the world’s greatest food producing areas.
Prairie region
This region experiences extreme weather conditions and scanty rainfall, mainly suited for extensive mechanized farming and grazing.
Mediterranean regions
This does not mean the regions round the Mediterranean, these consist of those areas of the Earth with typical Mediterranean climate of warm wet winters and hot dry summers. These areas include South Africa and Southern Australian where the vegetation is also like that of the Mediterranean. Annual rainfall is between 20 to 40 inches. The vegetation found in these areas are oak, vine, wheat etc., population is dense.
Savannah or tropical hot grassland regions
Found in the Tropics with high temperatures all year round. Rainfall occurs in the hotter season. The dominant vegetation is tall, coarse grass and trees. The Savannah areas lie between the desert and the forest. More than one-third of Africa is Savannah. Savannah areas are also found in Venezuela, Columbia, Brazil and Australia where they have local names.
Tropical forests
Tropical rain forests are among the most moist places in the world with rainfall reaching an average of 160 inches a year in the lowlands near the Equator. These regions are extremely hot and moist, with lots of vegetation and tall trees.
Monsoon land areas
They experience a complete reversal of wind direction over the year due to the differential heating and cooling of the land and the seas in Asia. Intense cooling in January leads to an area of high atmospheric pressure over Tibet and winds blow outwards. In July the situation is reversed; intense heat cause an area of low atmospheric pressure into which winds are drawn. Vegetation is as varied as the climate patterns. This region includes South and Southeast Asia.
Semi-deserts and deserts
Semi-desert areas have scanty and intermittent rainfall. This region usually experiences extreme temperatures. Vegetation is sparse and consists of salt bush, scrub and other stunted plants. Deserts have little or no rainfall and experience extreme temperature during the day and night. The summers are extremely hot and winters extremely cold. These areas are usually rocky or sandy with no vegetation except in patches called oasis where water is found. In the tropics the North-east and South-east winds blow towards the Equator, which become warm and usually contribute to dry weather due to lack of water vapour in the air. There are therefore deserts on the west side of all the continents around Latitudes 20 N 20 S. The situation is aggravated by the presence of cool currents in the oceans to the west of the continents. On-shore winds heat up rapidly once they cross the coast and they too become dry. The deserts extend into the hearts of the continents far from the moist influence of the sea.
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