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themselves to seasonal changes in order to exploited forests out of his greed, and it has
survive. When there is a major large scale change resulted in large scale deforestation. This has
in the climate, the plants may not survive. resulted in influencing the environment to a large
Contrary to plants, animals are able to move from extent. The situation has already become serious.
one place to another and have a better chance of Mahatma Gandhi once remarked, “Nature can
survival. The yearly migration of animals and birds meet all our needs, but not a single greed.” This
is a common feature in the world. Every year, holds true of our forests too.
thousands of cranes migrate from Siberia to The people are gradually becoming aware of the
Bharatpur Bird Sanctuary in India during winter to
importance of trees and governments of different
escape the icy cold of Siberia.
countries are now paying attention to the
Wind plantation of trees, yet the rate of progress is not
very satisfactory.
Plant life is affected by the velocity of wind also.
Wind checks the growth of plants through
increase in the rate of transpiration. In the prairies TYPES OF FORESTS IN THE WORLD
(North America), winds do not allow tall trees to Generally, forests are of two types—evergreen and
grow. deciduous. Evergreen trees do not shed their
leaves all at one time. They shed some leaves at
NATURAL VEGETATION one time. In hot and humid climates, evergreen
trees have broad leaves, while in cold climates
We have noticed above how different factors
influence vegetation of an area. The plant species they have needle like leaves and bear cones. On
living in association with each other in a given the other hand, deciduous trees shed trees once in
a year and generally have broad leaves.
environmental framework is called natural
vegetation. The major vegetation types of the Evergreen Forests
world may be classified as—forests, grasslands,
The evergreen forests can be divided into four
scrubs and tundra. How these groups are groups—tropical evergreen forests, temperate
distributed throughout the world depends upon
evergreen forests, Mediterranean forests and
the availability of moisture. Temperature causes
coniferous forests.
variations in species. So, one may find forests
between 60°N and 60°S on both sides of the Tropical Evergreen Forests
Equator. However, the types of trees in these The tropical evergreen forests are found in hot and
forests depend upon the range of temperature. humid areas. Very dense forests are found in the
regions getting more than 200 cm average rainfall.
SIGNIFICANCE OF FORESTS They are generally found in the equatorial regions
The forests are very important for life on the earth. and coastal regions. These trees have broad leaves
They are the lungs of the world as they give out to allow transpiration of surplus moisture. Some of
oxygen, much needed by the living beings. In these trees may be shedding trees, but others will
addition to this, they are a source of wood, keep blossoming. Evergreen trees may vary from
medicine, food and other products. They conserve very tall trees to undergrowth.
the soil and prevent soil erosion. They check the These trees grow close together. The thick growth
velocity of wind and floods. They give shelter to allows the branches of different trees grow
wildlife. Thus, they form an important part of the together. This thickness forms a canopy at the top,
ecosystem. which does not allow sunlight to reach the
Such an important resource ought to be handled ground. As different species of trees grow in a
carefully; unfortunately, the reverse has occurred. limited area, commercial exploitation of these
Man has started to interfere with forests. He has forests becomes difficult.
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