The Pará rubber tree (Hevea brasiliensis), often simply called rubber tree, is a tree belonging to the family Euphorbiaceae and the most economically important member of the genus Hevea. It is of major economic importance because its sap-like extract (known as latex) can be collected and is the primary source of natural rubber.
The tree can reach a height of over 30m (98.4 feet). The white or yellow latex occurs in latex vessels in the bark
, mostly outside the phloem
. These vessels spiral up the tree in a right-handed spiral
which forms an angle
of about 30 degrees with the horizontal.
Once the trees are 5-6 years old, the harvest can begin: incisions are made orthogonal to the latex vessels, just deep enough to tap the vessels without harming the tree's growth, and the sap is collected in small buckets. This process is known as rubber tapping
. Older trees yield more latex, but they stop producing after 26-30 years.
The Pará rubber tree initially grew only in the Amazon Rainforest
. Increasing demand and the discovery of the vulcanization
procedure in 1839 led to a boom in that region, enriching the cities of Belém
. The name of the tree derives from Pará
, the second largest Brazilian state, that contains Belém as capital, mainly city and tech-financial centre.
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. Rubber trees were brought to the botanical gardens at Buitenzorg, Java in 1883. 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.
The wood from this tree, referred to as parawood or rubberwood, is used in the manufacture of high-end furniture. It is valued for its dense grain, minimal shrinkage, attractive colour and acceptance of different finishes. It is also prized as an "environmentally friendly" wood, as it makes use of trees that have been cut down at the end of their latex-producing cycle.
The genus Hevea
is also known as:
Zhang, J., Huss, V.A.R., Sun, X., Chang, K. and Pan, D. 2008. Morphology and phylogenetic position of a trebouxiophycean green algae (Chlorophyta) growing on th rubber tree, Hevea brasiliensis
, with the description of a new genus and species. Eur. J. Phycol. 43(2)
: 185 - 193.