Rubber Series: Caoutchouc and its ultivation
Nowadays, the main growing region for natural rubber is the tropical area of Asia (Malaysia, Indonesia, Thailand, Vietnam, Sri Lanka, China and India). The cultivation area of crops is often far away from the country of origin because plants are often not as heavily infested by pests or diseases as in their home country, provided that the pests haven’t also been transported e.g. with the seed or the plant. The Hevea Brasiliensis do not form compact forests, but grow scattered among other trees, so that you rarely find two or three Hevea trees side by side. Their cultivation is restricted to lowlands in which a uniform temperature (optimal temp. 26–28 °C) and a strong rainy season prevail (125 to 150 rainy days per annum). Furthermore, it needs a high atmospheric humidity of about 80%, bright sunshine with an average rate of 6 h per day and absence of strong winds.
The work of a rubber plantation is done very scientifically. Every tree of a rubber estate is carefully looked after and therefore, some special laborers are employed. Rubber is planted from the seedlings. For making the rubber plants high-yielding, its seedlings are grafted. This is done in a very interesting way. When the seedlings are about 5 or 6 cm. in diameter, buds from the selected high-yielding trees are grafted on to the seedlings. This is done to transmit the high-yielding quality of the “mother-tree”. The graft is, then, kept bound and left for a few weeks. After a few weeks the grafted buds sprout and the old tree is cut off just above the point of union. The grafted seedlings are planted in rows, 5 or 6 meters apart from each other. In order to conserve the soil and its fertility, some crop covers (leguminous creepers etc.) are planted in between the seedling trees.
A variety of diseases and pests threaten the tree during its period of growth, so that there is a potential annual loss of revenue of about 25 percent. After five to eight years, the tree reaches its maturity phase and is used for tapping the latex milk. The Hevea tree has its maximum output between the 12th and the 15th year. The rubber tree may live for a hundred of years or even more. But its economic life period in plantations is only around 32 years. Then, the caoutchouc tree stops its latex production and is chopped down. The wood is utilized by the furniture industry and is an important export product in Southeast Asia.