Natural rubber cultivation

In Southeast Asia the ambitious expansions of oil palm plantations in the tropical areas have made this region by far the main palm oil producing region in the world outdistancing natural rubber cultivation as the key agro resource in Malaysia (Figure 9.1.4). 

Roy Choudhury N., Bhowmick A.K., and De S.K., Thermoplastic natural rubber. Natural Rubber Biology, Cultivation and Technology (Sethuraj M.R. and Mathew N.M., eds.), Elsevier, New York, 1992. Elliot D.J., Natural rubber systems. Development of Rubber Technology 3 (Whelan A. and Lee K.S., eds.). Applied Science, New York, 1982. 

Natural rubber obtained from cultivated trees as opposed to that obtained from trees growing wild in the jungle. The size of a plantation varies from the large estate of several thousand acres down to the smallholdings of a few acres worked by the owner and his family. Such smallholdings produce a significant proportion of the world s NR output. 

Natural rubber obtained from trees growing wild and not cultivated in either plantations or native small holdings. The output of wild rubber is now insignificant. 

Sethuraj. M R, and NM. Mathew Natural Rubber Biology, Cultivation, and Technology, Elsevier Science. New York, NY, 1992. 

The latex of milkweeds and other species in the family Asclepiadaceae can be used to make a natural rubber. During World War II, when supplies of rubber from Asia were not readily available in North America, research was undertaken to see whether this strategically important material could be obtained from milkweeds under cultivation. However, the yields of rubber were too small to make this enterprise worthwhile. 

National Academy of Sciences (1977). Guayule An Alternative Source of Natural Rubber. Washington, D.C. Jojoba Feasibility for Cultivation on Indian Reservations in the Sonoran Desert Region. Washington, D.C. 

Sethuraj MR, Mathew NM (1992) Natural rubber biology, cultivation and technology in crop science. Elsevier, Amsterdam... 

Natural rubber is obtained from the juice present in various trees and shrubs which grow best in tropical countries. On account of the importance of rubber commercially the trees which yield it are grown systematically on plantations formerly the supply was obtained from natural forests. The intensive cultivation of rubber trees has had a marked effect in lowering the price and insuring a steady supply of rubber. 

Keywords Natural rubber, Hevea brasiliensis, cultivation, modification, primary processing, manufacturing techniques, pneumatic tyre, non-tyre products, vulcanization, green commodity... 

The original habitat of the rubber tree in the Amazon valley is situated within 5° latitude and at altitudes less than 200 m. Naturally, the trees evolved in this environment prefer warm and humid weather [9]. The climatic conditions suitable for optimum growth of rubber trees include an annual rainfall of not less than 2000 mm, evenly distributed without any marked dry spell, a maximum temperature of 29-34°C and a minimum of 20°C or more, high atmospheric humidity of around 80% with moderate wind, bright sunshine amounting to about 2000 hours per year at the rate of six hours per day throughout the year [10]. Rubber needs a well-drained, fairly deep, loamy soil with a pH value of 4.5-6.0. South East Asia is particularly suitable for rubber cultivation as are countries in West Africa. Although not ideally suited, rubber is now successfully cultivated even up to latitudes of 25° in countries such as India and China. 

P.S.Rao and K.R.Vijayakumar, "Climatic requirements" in M.R.Sethuraj and N.M.Mathew, eds. Natural Rubber Biology, Cultivation and Technology, Elsevier Science Publishers, Amsterdam, 1992. 

Natural rubber of the best quality is prepared by coagulating the latex of the Hevea brastliensis tree that is primarily cultivated in the Far East. However, there are other sources such as the wild rubbers of the same tree growing in Central America, guyayule rubber coming from shrubs grown mostly in Mexico, and balata. Balata is a resinous material and carmot be tapped like the Hevea tree sap. The balata tree must be cut down and boiled to extract balata that cures to a hard, tough product used as golf ball covers. 

We begin with two trees, both cultivated on plantations in Southeast Asia. One, Hevea brasiliensis, is a source of natural rubber and was innported from Brazil in the nineteenth century. The other, Isonandra gutta, is native to Sumatra, Java, and Borneo and gives a latex from which gutta-percha is obtained. 

Natural rubber can be obtained from nearly 500 different species of plants. The outstanding source is the tree Hevea brasiliensis, from which comes the name Hevea rubber. The tree grows best in damp, warm climates. It was first cultivated in Brazil and then imported to the Malay Peninsula, where the bulk of the world s rubber came before World War II. 

Natural rubber (NR) of the best quality is prepared by coagulating the latex of the Neva brasiliensis tree, which is cultivated primarily in the Far East. Another rubber is plantation leaf gutta-percha. This material is produced from the leaves of trees grown in bush formation or on plantations. These leaves are plucked and the rubber is boiled out to extract balata, which cures to a hard and tough product. Gutta-percha has been used successfully for more than 40 years as submarine cable. 

The natives of tropical America were preparing articles from the rubbery exudates of Hevea spp. (Euphorbiaceae) and Castilla spp. (Moraceae) trees well before discovery by Europeans in the early 17th century. Following the developments of vulcanization and other treatments, an enormous exploitation of rubber trees, particularly of Hevea brasiliensis, growing in the delta of the Amazon River and in its upper reaches west of Manaus, took place from 1827 onward. Large fortunes were made by a few European entrepreneurs at the expense of the lives of many local and imported laborers. After some difficulties, rubber trees were cultivated in Malaysia in 1880, and subsequently in neighboring countries, from which most of the natural rubber of today is derived. Following severe competition from syn-... 

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