Biosphere: Distribution of forests, plants, grasslands, and their economic significance. Plantlife depends on photosynthesis, which in turn needs both water and sunlight.
Based on Sunshine and Temperature, plants are classified into 3 categories:
- Tropical Plants: These plants have a high tolerance for torrid climate i.e., high temperatures. High rainfall throughout the year. Hence, the fall of leaves and regeneration of leaves can happen throughout the year. These evergreen forests are seen where rainfall is the year and greater than 200cms annually.
- Temperate Plants: These have moderate and that too seasonal. Here leaf fall is in the dry season. With seasonal leaf fall, reduced transpiration helps the trees conserve water. The temperate forests are also called Deciduous Forests. Here rainfall is about 50-200 cms annually happens seasonally.
- Polar Desert: Cold, dry, and leeward.
Combining these we obtain the following:
These cover permanently hot and humid equatorial regions. These are evergreen forests with the greatest forest density with maximum biodiversity. On this account, these forests are called the ecological lifeline of earth. (or) Lungs of the earth. These forests cover Amazon Basin (Brazil), Congo Basin (Africa), and Southern European Asia & Borneo (Asia). Amazon is the largest equatorial rainforest in the world with the greatest concentration of biodiversity and greatest forest density. On these grounds, these are locally known as the Selvas.
Equatorial rainforests are stratified. This is because of competition for sunshine among plants. Mahogany, Ebony, Rosewood, and Dye wood are the most important plant species. These are all tropical hardwoods. Equatorial rainforests are insignificant for commercial uses as forest density is too high and it is difficult to construct and maintain transport and communication systems. Climate is hot and humid. Infections are common. Logs are too heavy to be transported by rivers and streams.
The equatorial region is dominated by plantations of rubber, cocoa, and coffee. Brazil is the world’s largest producer of rubber and Ghana is the world’s largest producer of cocoa.
Tropical Monsoon Forest
These are deciduous forests growing in hot & humid tropical regions with seasonal rainfall. Indian subcontinent or South Asia has the largest expansion of tropical deciduous forest. Sal, Shisham, Teak & Sandalwood are the major trees of these forests. These are timber sources. Myanmar is the largest producer of teak. India is the largest producer of Sal, Sesame & sandalwood.
Intensive Subsistence Farming dominates Tropical Monsoon Forests especially in the plains and coastal plains of South Asia. These are overpopulated areas. Hence there is high pressure on land. Consequently, most agricultural landholding is small. So, to increase production, many crops are grown a year. This is called Multiple Cropping. If multiple crops grown in the year on small agriculture, it is called Intensive Agriculture. Due to the large population whatever is produced is consumed. This is called Subsistence Farming. E.g. India & China are the largest producers of rice & wheat but they hardly export it due to self – consumption. Such a state of agriculture is called Intensive Subsistence Farming.
These are associated with tropical regions that are semi-dry. If the annual rainfall is between 30 cm – 70 cm, the area is classified as Semi-Dry. Tropical grassland is a transitional zone between the deciduous forests region and dry regions. Some Tropical Grasslands include Savanna in Africa, Campos & Llanos in South America. Savanna is the largest grassland in the world. The Tropical grasslands are characterized by tall grasses and scattered trees.
This landscape is known as Parkland. The tall grasses are known as Elephant grass, and these are seasonal. Tropical grasslands are known for nomadic lifestyles characterized by animal hunting. Hence these regions are also known as Big Game Country. Nomads continuously move with their animal herds in search of water and grass. The availability of both is seasonal. This way of life is called Nomadic where animal herbs are their source of food & livelihood. For example, Masai Kenya. Several national parks have been established to product wildlife, and one of the most famous national parks includes the Masai Mara National Park in Kenya.
- Transhumance: If nomads have a seasonal pattern of migration, it is called transhumance. E.g: The Gaddi & Baterwal people of J & K and Himachal Pradesh.
- The First National Park the world is the Yellow Stone National Park (U.S.A.). The First National Park of India is the Jim Corbett National Park (Uttarakhand).
These are hot & dry regions dominated by Xerophytes or tropical thorn vegetation like Cactus, Acacia (Babul). The forest density & bio-diversity in tropical deserts are extremely low.
These are on the west coast of continents in Warm Temperate Regions. The summers are dry and winters are characterized by rainfall which is due to on-shore Westerlies. Our. Chestnut, cork, olive & Eucalyptus are important trees whose bank & leaves are thick which prevents evapotranspiration & subsequent loss of water. These plant species are called Sclerophyls. Citrus Orchards & Viticulture are dominant forms of agriculture. Viticulture is the systematic culture of groups and the production of wine. This region is known for producing the finest wines in the world. Champagne from France, Sherry from Spain, Port Wine from Portugal are some of the known wines.
Some known temperate grasslands include; these are associated with Temperate Continental Climate; these grasslands are covered by short & perennial grasses. Temperate grasslands are devoid of trees. The major economic activities associated with temperate grasslands are:
- Extensive Commercial Farming
- Animal Ranching
These cover the cool temperate continental climate of Eurasia & North America. These are also called Coniferous Forests. Russia has the longest cover of Taiga Forest and also the largest forest cover in the world. Brazil covers a close second. Coniferous forests are a source of softwood like Pine, Chir, Spruce, Juniper & birch. Their timber is used in construction, sports goods, pulp, and paper. The USA is the largest producer of pulp& paper in the world; Canada is the largest producer of newsprint.
These cover Sub-Polar Regions of the Northern Hemisphere (there is no continental landmass in the sub-polar regions of the Southern Hemisphere). The land surface is covered by snow during the winter season. In short and cool summers when snow disappears, Mosses &Lichen(s) appear. Tundra regions are inhabited by Eskimos who live in Igloo (made of snow).Log in or Register to save this content for later.