Bonnie Smith age 10 of Toronto  Canada

What is rubber caused by?

Rubber is caused by a tree. Several different trees give the stuff from which rubber is made  The tree that gives rubber for making auto tires is a cousin of the tree that yields the stuff for making our chewing gum. Most of the workaday rubber comes from the hevea tree„

This tree is very choosy about where it will grow. It begins  life as a seedling in a nursery. When it is a year old its top is cut off  This is to prepare it for grafting. A twig is then from an older hevea that has proved it can yield plenty of rubber. A slit is made in the bark of the new trees The twig is cut in a special way and sealed under the bark.  There it grows. In time it becomes the main trunk of the new hevea tree;.

The grafted tree is set out in a plantation. About 150 new trees share an acre of ground. Climate and temperature must be right. The hevea grows best within 1000 miles of the equator. Fine rubber plantations grow in Malayan Ceylon  Burma and Indonesia  which supplies half the world’s rubber.

A new tree grows six to nine feet each year„ Should its bark be scratched. it has a special way of patching the wound. A juice called latex flows out from tiny tubes in the inner bark.. The latex teems with soft little pear‑shaped bodies. As the juice dries in the air  these bodies gel to form a rubber patch over the wound..

At the age of six  our tree is ready to yield  latex. Its work life begins one morning  early. Someone arrives carrying a pail a spout a gouge and maybe some chemicals. The gouge is used to cut a groove in the outer bark. This cut begins about four feet from the ground and slopes down to half way around the trunk

Naturally the hevea tree at once pours out latex to patch the wound. The juice runs down the cut and is lead off by the spout into the pail. Sometimes the plantation worker dabs on some ammonia to stop the juice from gelling too fast. In a few hours he will. return to gather up the latex in the pail.

In two days a slimmer groove will be out below the first. This will go on every day for a few years. Then the other half of the tree will be used. The first side gets a chance to grow new bark. At 25 the prime of its life our tree may yield 30 pounds of latex a year.

The raw latex is made into rubber at a factory. It is dumped into vats of water and acid. In a few days the acid causes the pear shaped bodies to gel and float in a mass. This is rubber. There may be a pound of it in three pounds of later It is rolled to squeeze out the water. Some is pressed into thin sheets and dried for weeks in the air. Most of it is smoked for a week or so and then rolled into grooved sheets The sheets of rubber are finally tied into bales.. They are shipped to makers of rubber goods around the world