Hevea brasiliensis

Common name: Rubber tree

Other common names: Rubbertree

Names in non-English languages: Spanish Thailand Portuguese

Description

Originating from the humid tropical forests of Brazil, Bolivia, Colombia and Peru, the Rubber Tree is valued for its latex, which is the world's principal source of natural rubber. 

It is a tall, fast-growing tree reaching up to 40 m (130 ft) in native forests, though is more commonly 15 to 20 m (50 to 65 ft) tall. 

It develops a straight, round trunk with smooth light grey, often mottled bark and a moderately branched crown. The branches tend to angle upward in closely spaced forests, forming a narrow crown, though in open spaces they grow more outward forming a compact, rounded shape.

The leaves are compound, being made up of three oval leaflets, each leaf-like in appearance, dark green above, light green below and are deciduous, falling off the tree in the dry season. New leaves start to grow at the beginning of the rainy season.

The flowers are small and insignificant with hairy, whitish to pale yellow petals and bloom in the rainy season, coinciding with new leaf growth. They are followed by egg-shaped seed capsules with a smooth brown shell, patterned in black markings. When mature they burst open with a popping sound and scatter their seed a considerable distance from the parent tree.

Use

A sticky, white latex is tapped from the trunk using a series of connected incisions that allows the latex to flow into a receptacle. After it is collected, the latex is processed by warming it over a fire until it coagulates and it is then shaped into crude rubber balls ready for further processing into rubber products. The finished, crude rubber is used to manufacture a range of products, among them rubber gloves and condoms. In the early 1900's, the manufacture of automobile tyres from rubber led to its mass commercialisation.

Yields of fresh latex is influenced by a variety of factors, including climate, soil and planting densities, which affects trunk diameter among other things. Annual yields in commercial plantations range from 1000 to 1500 kg of latex per hectare (900 to 1300 lbs per acre).

The flowers produce abundant nectar suitable for honey production, with flows lasting up to forty days over the flowering period. It is classed as a major honey plant in India, with Kerala and Karnataka states, in the south of the sub-continent the main producers.

Reported yields vary from 10 to 40 kg (22 to 88 lbs) of honey per colony per season, and it is estimated each tree has the potential to produce enough nectar to yield 3 kg (6.6 lbs) of honey. The honey itself is clear, water-white to pale yellow, very sweet and quick to granulate, with crystals starting to form after around two months.

The seed kernel, which amounts to 50% of the seed, contains about 45% of a red coloured drying oil known as 'Para seed oil'. It is used chiefly in the manufacture of soap but after refining can also be used in paints. It has also reportedly been successfully engine-tested as a biodiesel. The leftover cake or meal can be used as a fertilizer or feeding stock.

Climate

Grows naturally and yields good quantities of latex in humid to very humid tropical lowland climates, generally frost-free areas with annual lows of 19 to 25 °C, annual highs of 27 to 35 °C, annual rainfall of 1600 to 4000 mm and a dry season of 4 months or less.

Rubber trees will not thrive in areas with a long or pronounced dry season, with frost or where the average low of the warmest month is below 10 °C (50 °F).

How to grow

New plants are usually grown from seed. It performs best on deep, rich, free-draining clay and loam soils of an acid to neutral nature, generally with a pH of 4.5 to 7.0 and on sites with light shade to partial sun exposure. The trees are ready to be tapped for their latex when around five to six years old.

Problem features

The mature fruit eject their seed with force, propelling them up to 15 m (50 ft) away from the parent plant. It is reported as an invasive species, a serious weed class, in at least one reference publication and as having naturalised in Australia, where it is also recorded as a weed of the environment. It would appear it is a high weed risk under conditions optimal for germination and growth.

Where it will grow


References

Books

  • Adams, C. D. 1972, Flowering plants of Jamaica, University of the West Indies, Mona, Greater Kingston

  • Barwick, M., et al. 2004, Tropical & subtropical trees : a worldwide encyclopaedic guide, Thames and Hudson, London

  • Bradbear, N. 2009, Bees and their role in forest livelihoods : a guide to the services provided by bees and the sustainable harvesting, processing and marketing of their products, Food and Agriculture Organization of the United Nations (FAO), Rome

  • Crane, E., Walker, P. & Day, R. 1984, Directory of important world honey sources, International Bee Research Association, London

  • Food and Agriculture Organization of the United Nations (FAO) 1986, Food and Fruit-bearing Forest Species, 3 : Examples from Latin America, FAO Forestry Paper no 44/3, Rome

  • Hill, A. F. 1952, Economic botany : a textbook of useful plants and plant products, 2nd ed, McGraw-Hill, New York

  • Jamieson, G. S. 1943, Vegetable fats and oils : their chemistry, production, and utilization for edible, medicinal and technical purposes, 2d ed, Reinhold, New York

  • Jensen, M. 1999, Trees commonly cultivated in Southeast Asia : an illustrated field guide, 2nd ed., Food and Agricultural Organisation of the United Nations (FAO) Regional Office for Asia and the Pacific (RAP), Bangkok

  • Lopez, C., et al. 2004, Riches of the forest: fruits, remedies and handicrafts in Latin America, Center for International Forestry Research (CIFOR), Bogor, Indonesia

  • Lorenzi, H. 2002, Brazilian trees : a guide to the identification and cultivation of Brazilian native trees. Vol. 1, 4. ed, Instituto Plantarum de Estudos da Flora, Nova Odessa, São Paulo

  • Luna, R. K 1996, Plantation trees, International Book Distributors, Dehradun, Uttarakhand

  • Macmillan, H. F. 1943, Tropical planting and gardening : with special reference to Ceylon, 5th ed, Macmillan Publishing, London

  • Marshall, E. (Elaine) & Schreckenberg, Kathrin & Newton, A. C & UNEP World Conservation Monitoring Centre 2006, Commercialization of non-timber forest products : factors influencing success : lessons learned from Mexico and Bolivia and policy implications for decision-makers, UNEP World Conservation Monitoring Centre, Cambridge

  • Mors, W. B & Rizzini, C. T. 1966, Useful plants of Brazil, Holden-Day Publishing, San Francisco, California

  • Randall, R. P. 2002, A global compendium of weeds, R.G. and F.J. Richardson Press, Melbourne

© All rights reserved Iplantz 2020