Rubber Series: The Rubber Tree –
The tree has a whitish bark and three-parted leaves, somewhat like our horse-chestnuts in Europe, becoming some 30-40 m (in culture 20 m) tall.
For growing well, tropical climate is needed: approximately 2000 mm rainfall and an average temperature of 27° Celsius.
Tapping of rubber is possible over a tree's lifespan of 30 years. The beginning is at an age of 5-7 years following special techniques cutting the bark. When cutting the growth layer of the tree, the cambium, mustn't be injured.
From the cut bark, a white milky juice begins to flow abundantly. The sap is collected in little tins fixed at the tree's deepest point of cutting. All two days, the cutting is prolonged, thus the whole stem can be used down to its basis. The tree will regenerate the bark, so, after about 15 years tapping, the cuttings can be repeated, beginning again from head-level. The aging tree can be stimulated by chemicals liberating ethylene-gas for getting a higher flow of sap.
An experienced tapper is able to treat 400-500 trees within 3-4 hours. Beginning his work at 6°° o'clock in the morning, he can collect the latex milk 5 hours later when the flow from the cutting begins to stop. Rainy days are days without tapping works, because the milk is water soluble.
Collected in buckets 1-2 hours after cutting, the latex is brought to central points, then to the factory without any loss of time. There the sap is prevented from coagulation by adding ammonia. With trucks the latex milk is brought to ships for export or processed to raw rubber in the factory by adding acids like vinegar.
The same principle is used by the "primitive" method of the inborn, when dipping a wooden stick into the latex milk and coagulating to latex by smoking over a fire - the smoke containing vinegar-acid also. Thus, layer by layer is brought on the stick, finally producing a raw-latex bale.