Rubber

One of the most interesting stories of plant life is the history of the rubber tree(Hevea brasiliensis). From the very early days of its discovery in South America, when the conquering Spanish saw children playing with rubber balls it was realized that rubber had water proofing and other properties which made it valuable. The real boom for the rubber industry came when rubber tyres were made. Whole books have been written about it and the way in which world history has been changed by this indispensable substance. Although originally from South America, rubber trees are now grown throughout the tropics, especially in South-East Aisa. The rubber begins life as a white latex which is obtained by cutting grooves in the bark of the trees. First it goes through a chemical process which results in a sheet of crepe rubber and in this form it can be transported. Further processing is necessary before it is made into such items as tyres. Nowadays synthetic materials are generally mixed with natural rubber. A few other plants have been used to produce rubber, particularly in war-time when the transport of tropical rubber was difficult. A species of dandelion was used for this purpose in the Second World War, the white sticky latex producing a rather inferior grade of rubber. Another form of latex, from trees of the Sapotaceae family, is used for chewing gum.