The Pará rubber tree (Hevea brasiliensis) is a tree belonging to the family Euphorbiaceae. It is of major economical importance because its sap (known as latex) can be collected and used to make rubber.
The tree can reach a height of over 30m; older trees yield more latex. The latex occurs in latex vessels in the bark, mostly outside the phloem. These vessel spiral up the tree in a righthanded spiral which forms an angle of about 30 degrees with the horizontal. Incisions are made orthogonal to these vessels, just deep enough to tap the vessels but not harm the tree's growth.
Rubber tree plantation in Phuket, Thailand
The leaves of a rubber tree
The para rubber tree initially grew only in tropicalSouth America, in the Amazon region. Increasing demand and the discovery of the vulcanization procedure in 1839 lead to a boom in that region, enriching the cities of Manaus and Belém.
There had been an attempt made, in 1873, to grow rubber outside Brazil. After some effort, twelve seedlings were germinated at the Royal Botanic Gardens, Kew. These were sent to India for cultivation, but died. A second attempt was then made, some 70,000 seeds being sent to Kew in 1875. About 4% of these germinated, and in 1876 about 2000 seedlings were sent, in Wardian cases, to Ceylon, and 22 sent to the Botanic Gardens in Singapore. Once established outside its native country, rubber was extensively propagated in the British colonies. By 1898, a rubber plantation had been established in Malaya, and today most rubber tree plantations are in Southeast Asia and some also in tropical Africa. Efforts to cultivate the tree in its native South America were unsatisfactory.
Rubber is an elastic hydrocarbon polymer which occurs as a milky emulsion (known as latex) in the sap of a number of plants but can also be produced synthetically.
The para rubbertree initially grew in South America, where it was the main source of what limited amount of latex rubber was consumed during much of the 19th century.
Rubber as a clothing material is fetishized by some people, perhaps on the basis that the garment forms a "second skin" that acts as a surrogate for the wearer's own skin.
The rubber is obtained by incising the stems of the vines and coagulating the latex by exposure, by admixture with acid vegetable juices or by heating.
The root rubber prepared by the natives of the Congo and the S. Sudan is extracted partly from the roots of Land olphia or from the rhizomes of Landolphia Thollonii or Carpodinus lanceolatus.
It is a large forest tree of upright habit extending to 60 or 70 ft. in height and 3 to 4 ft. in diameter.
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