NCERT class VII : Our Environment – Natural Vegetation and Wild Life – Chapter 6
Points to remember
With the change in height, the climate changes and that changes natural vegetation. The growth of vegetation depends on temperature and moisture. It also depends on factors like slope and thickness of soil.
Natural vegetation is generally classified in to three broad categories as follows:
- Forests: grow where temperature and rainfall are plentiful to support a tree cover. Depending upon these factors, dense and open forests grown.
Types of Forests
- Tropical Evergreen Forests : also called tropical rainforests, These thick forests occur in the regions near the equator and close to the tropics. These regions are hot and receive heavy rainfall throughout the year. As there is no particular dry season, the trees do not shed their leaves altogether. This is the reason they are called evergreen. The thick canopies of the closely spaced trees do not allow the sunlight to penetrate inside the forest even in the day time. Hardwood trees like rosewood, ebony, mahogany are common here.
- Tropical Deciduous Forests : are the monsoon forests found in the large part of India,northern Australia and in central America .These regions experience seasonal changes. Trees shed their leaves in the dry season to conserve water. The hardwood trees found in these forests are sal, teak, neem and shisham. Hardwood trees are extremely useful for making furniture, transport and constructional materials. Tigers, lions, elephants, langoors and monkeys are the common animals of these regions.
- Temperate Evergreen Forests : located in the mid latitudinal coastal region. They are commonly found along the eastern margin of the continents, e.g., In south east USA, South China and in South East Brazil. They comprise both hard and soft wood trees like oak, pine, eucalyptus, etc.
- Temperate Deciduous Forests: Towards higher latitudes, there are more temperate deciduous forests. These are found in the north eastern part of USA, China, New Zealand, Chile and also found in the coastal regions of Western Europe. They shed their leaves in the dry season. The common trees are oak, ash, beech, etc. Deer, foxes, wolves are the animals commonly found. Birds like pheasants, monals are also found here.
- Mediterranean Vegetation:The west and south west margins of the continents have Mediterranean vegetation It is mostly found in the areas around the Mediterranean sea in Europe, Africa and Asia, hence the name. This kind of vegetation is also found outside the actual Mediterranean region in California in the USA, south west Africa, south western South America and South west Australia. These regions Let’s do are marked for hot dry summers and mild rainy winters. Citrus fruits such as oranges, figs, olives and grapes are commonly cultivated here because people have removed the natural vegetation in order to cultivate what they want to. There isn’t much wildlife here.
- Coniferous Forests In the higher latitudes (50° – 70°) of Northern hemisphere the spectacular Coniferous forests are found (Fig. 6.13 a and b). These are also called as Taiga. These forests are also seen in the higher altitudes. They are tall, softwood evergreen trees. These woods are very useful for making pulp, which is used for manufacturing paper and newsprint. Match boxes and packing boxes are also made from softwood. Chir, pine, cedar are the important variety of trees in these forests. Silver fox, mink, polar bear are the common animals found here.
- Grasslands: grow in the region of moderate rain.
- Tropical grasslands: These grow on either side of the equator and extend till the tropics . This vegetation grows in the areas of moderate to low amount of rainfall. They can grow very tall, about 3 to 4 metres in height. Savannah grasslands of Africa are of this type. Elephants, zebras, giraffes, deer, leopards are common in tropical grasslands
- Temperate grasslands: These are found in the midlatitudinal zones and in the interior part of the continents. Usually, grass here is short and nutritious.Wild buffaloes, bisons, antilopes are common in the temperate region.
- Thorny bushes: These are found in the dry desert like regions.Tropical deserts are located in the western margins of the continents. The vegetation cover is scarce here because of scanty rain and scorching heat.
The growth of natural vegetation is very limited in Polar region. Only mosses, lichens and very small shrubs are found here. It grows during the very short summer. This is called Tundra type of vegetation. This vegetation is found in the polar areas of Europe, Asia and North America. The animals
- Shrubs: Thorny shrurbs and scrubs grow in the dry region