Rubber

The Brazilian rubber tree ~ Hevea brasiliensis ~ is a member of the Euphorbiaceae family, a family known for producing latex. But none of the other plants in this family have been so valuable to the industrialized world, nor can any make claim to a more colored past than Hevea. The work of tapping rubber trees is still a process done by hand. The vessels containing latex are located in the inner bark, within the phloem tissue. To obtain the latex, incisions are made along the trunk at an angle, leading to a collection cup at the bottom. The collected latex is then coagulated with a mild acid, rolled out, and smoke dried.¹
This same knowledge was used by Amerindians in Ecuador and Brazil for making torches, boots, bottles and syringes. The rubber syringe, used in both ceremonial and medicinal squirts and enemas by Native Amazonians, was re-invented by European scientist around 1790.²

To the Aztec and Mayan civilizations, rubber held great religious and social value. The Mexican rubber tree ~ Castilla elastica ~ was burnt or paraded in the form of figurines, or paintings on bark-paper during ceremonies of human sacrifice. Bouncing rubber balls were made by mixing latex with crushed morning glory vines. These balls, used for the great ball game Tlachtli, were even valued as currency.²
Natives to the Americas had several tropical plant species from which they obtained rubber. However, the tree that yielded the purest and most elastic rubber was Hevea brasiliensis, know as Para rubber in commerce. At its peak, rubber trade accounted for almost 40% of Brazil's export revenues.¹

Rubber's true usefulness was not seen until the advent of vulcanization techniques in 1839, more than three centuries after Amerindians introduced it to early explorers. ¹ Prior to 1839, rubber had been used as water-proofing for cloth, but cracking in winter and becoming tacky and malodorous in summer limited its success. Vulcanization, a process developed by Charles Goodyear and Thomas Hancock, uses sulphur, lead oxide and heat to stabilize rubber.²

Rubber in Brazil

Early rubber prospectors made use of Hevea brasiliensis growing along watercourses, where its floating seeds had a tendency to find purchase. However, the largest specimens were generally found on higher ground, usually no more than two to three tappable specimens per hectare.¹

This natural wisdom of diversified planting was largely ignored in Brazilian rubber plantations, leading to the devastating effect of South American Leaf Blight ~ Mycrocyclus ulei.¹ The initial prosperity Brazil experienced from the rubber industry, which found plantation owners living in absurd extravagance (read: lighting cigars with money), was stopped short due in a large part to Mycrocyclus. Competition with plantations of imported Hevea in Southeast Asia only exacerbated the problem. To this day Brazil is still searching for ways to overcome Mycrocyclus in its plantations. And even with strict screening of plants that travel between Brazil and Southeast Asia, it may only be a matter of time before Mycrocyclus finds its way across the ocean.¹

Another factor that has kept Hevea’s homeland from experiencing the wealth that rubber has created is the use of synthetic rubbers. For many applications synthetic rubbers made from refined petroleum have proven cheaper to use. However, some of natural rubber's qualities, such as resistance to heat accumulation, make it essential in such applications as aircraft tires.² And with diminishing sources of petroleum and increased concern for the environmental effect of industry, rubber may again find its way to high demand.