Trees and forests

Man's dependence on plants is indispensable. It is this dependence for

food, shelter and clothing that has led him to explore all possible ways to

reserve plants from being lost to the ravages of natural or man-made

calamities. Accordingly, man has used different methods to overcome these

calamities. While doing so, scientists hit upon a technique whereby plants

only be restored from being lost but can also be developed into a

plant from a small plant part. This technique, called tissue culture

, subsequently proved to be a boon for mankind. Basically, tissue culture 

 is a technique by which small pieces of different parts of a plant body

called explants ) are grown on a nutritional media under completely sterile conditions. These explants divide and gradually develop either into

mass of cells called callus or after a few cell divisions differentiate

to form full-fledged plants

The concept of tissue culture dates back to 1878 when a German Botanist

ting said that from a small plant piece, a whole plant can be regeneration

ed. Later, other scientists like Haberlandt in 1902 postulated that cultivation

 of artificial embryos can be possible depending on the nutritional

A tree is a woody plant usually with a single stem. A large area well
covered with woody plants is a forest. The woody plants called shrubs
and bushes are smaller than trees and have usually more than one main
stem Trees are the largest living things on the Earth, and they live longer
than any animal. The tallest trees are mountain ashes which have grown
to well over 330 feet. The oldest trees are the Californian pines, some of
which are more than 4,500 years old. The age of a tree can be told by
counting the rings in the trunk. In most kinds of temperate trees (ie. grown
in neither very hot nor very cold climates ) , new wood is formed each year in a layer outside the wood of the previous year

The layers of wood, seen on the cut end of a felled tree, are circular and are called annual

rings. Each ring in the trunk of the wood represents one year of the tree's

life. In a year of good rainfall, the ring formed is wider than one formed

in the drier year. A record of rainfall can thus be read in tree rings.

Trees are important to our world for a number of reasons. Like all green

plants, they build up their food by the process known as photosynthesis

The by-product of this process is oxygen which is given off into the air

and replaces the oxygen which human beings and other animals take from

the atmosphere as they breathe. That is why the great forests have been

called the "lungs of the world". They make much of the oxygen we need

to live.

Did you know that around 270 eucalyptus trees or 460 bamboo plants per tonne of paper produced are saved by  the manufacture of hand made paper ?The hand made paper helps in preventing water ,land and air pollution because very small quantities of chemicals are used compared  to the large quantity of polluting chemicals used by paper mills.

Banyan is also considered unique in southern Asia because of its growth  and its shade which protects us from the burning sun.It has been a meeting point, a place of worship of man for ages.It is popular with the name of,'strangler fig' on account of its unusual growth. The birds,bats,and monkeys deposit the seeds of banyan in the rich soil, when it  grows, it sends aerial roots down the trunk of the supporting tree. So the roots that reach the ground choke the tree to prevent its trunk from being enlarged.