Hevea

Hevea is a genus of flowering plants in the family Euphorbiaceae. The most economically important species is Hevea brasiliensis, the rubber tree, native to the Amazon basin in northern South America. Several other Hevea species exist, but H. brasiliensis is by far the primary source of natural rubber.

Hevea brasiliensis is a tall evergreen tree, commonly reaching 20–30 meters in cultivation. It has smooth grey-brown bark and leaves that are typically composed of three leaflets. The tree contains latex in laticifer vessels throughout the bark, which is why tapping the tree releases a milky sap.

Uses and production are centered on natural rubber. The latex coagulates to form solid rubber, used in tires, gloves, tubing, and numerous other products. In plantations, tapping involves making shallow incisions in the bark and collecting the flowing latex in cups or collection systems. The latex can be processed into sheet rubber or converted into latex concentrates.

Distribution and cultivation have globalized rubber production. Native to tropical lowland forests of the Amazon, Hevea bra­siliensis was introduced to Southeast Asia in the late 19th century, where climate and economics favored large-scale rubber cultivation. Today major producers include Thailand, Indonesia, and Malaysia, with activity also in other tropical regions.

Ecology and threats include susceptibility to diseases and pests. The most historically significant threat was South American leaf blight (caused by Microcyclus ulei), which decimated wild populations and spurred breeding programs for resistant clones. Other diseases affecting plantations include root rot and cankers.

See also: Natural rubber, latex.