Rubber tapping is the process by which natural rubber (gum rubber) is collected. There are many species of trees that can be tapped for rubber; some of the more common species are Gutta-Percha (Palaquium gutta), rubber fig (Ficus elastica), Jelutong (Dyera costulata), Panama rubber (Castilla elastica), various spurges (Euphorbia species), and Guayule (Parthenium argentatum). Many of the early European explorers to the New World tropics were introduced to rubber that indigenous people obtained from tropical tree species. Rubber tappers would make a very shallow incision in the bark of a tree that would cut through the latex vessels. The dripping latex would then be collected in a vessel attached to the tree. In Central Kalimantan Jelutong trees were particularly important as a source of rubber.
Since rubber was a relatively unstable product it remained a curiosity until 1839 when Charles Goodyear invented vulcanization, a process that would make the elastic properties of rubber more permanent through treatment with heat, sulphur and white lead. The rubber product became harder, less soluble and more durable, and the plastic properties of this natural material could be brought to a desired shape. This discovery enabled the applications of rubber-derived products to greatly multiply and exploitation of many species of wild rubber-bearing plants intensified.
The tropical tree that was found to yield the purest, most elastic and most abundant rubber was known in commerce as Pará rubber, Hevea brasiliensis. This species was native to Brazil, northern Bolivia and eastern Peru. At one point the rubber trade brought in 40% of Brazils export revenue, all from wild trees.
Domestication of the Pará rubber tree was attempted in Brazil at great cost to large growers but was limited by severe disease issues. In South America a fungal disease of the Pará rubber tree called the South American leaf blight is caused by the ascomycete Microcyclus ulei. This fungus inhibits natural rubber production on a commercial scale in South and Central America. But as large companies were attempting and failing at establishing plantations in the Americas in the 1920’s and 30’s others were succeeding in Asia where the fungus does not exist.
The Malayan rubber industry has been described as one of the greatest achievements of Western colonial enterprise. Along with tin, it formed the backbone of Peninsular Malaysia’s economy, and its impact on the landscape was profound. By the end of the 1890’s many of the problems of cultivating Pará rubber in Malaysia had been resolved. It was found that initial spacing of 350 trees per hectare was shown to permit the most rapid growth and tapping could begin in seven years after planting. Tapping methods were much improved over those used in the Amazon. Instead of cutting with a small hatchet, knives were designed that excised thin slivers of bark. Trees could be tapped on alternate days throughout the year and yields would increase as the tree matured. In 1896 the first successful commercial grove of "Pokok Getah" was planted in Malaysia. Pará rubber is also less demanding in terms of soil fertility and topography than other introduced tree crops such as oil palm (Elaeis guineensis) and cocoa (Theobroma cacao).
Peninsular Malaysia is among the world’s most important rubber growing areas. Rubber "pokok getah" is also grown in the Malaysian states of Sabah and Sarawak on the island of Borneo. Together the 14 states produce almost 20% of the world’s natural rubber on 1.3 million hectares of land with production declining due to planting of other crops, especially Oil Palm. Eighty percent of this rubber comes from thousands of privately owned plots of land (small holders), usually less than 2.5 hectares (data from the Malaysian Rubber Board).
Pará rubber as a crop plant has found its place in the economies of producing tropical countries. It is the most widespread smallholder tree crop is Southeast Asia, nearly all the natural rubber used by tire manufacturers comes from Pará rubber. It contributes a substantial amount to the welfare of small farmers in the tropics worldwide. For many swidden fallow (slash and burn) farmers rubber constitutes their main source of cash, literally a bank account that can be tapped as needs arise. Collected rubber can also be stored or stockpiled to be sold when the price reaches a better level. Tapping rubber trees for latex has not been automated, and will not likely happen in the near future leaving the important natural rubber industry in the hands of small holders.