Family Name Hevea brasiliensis of the Family Euphorbiaceae Common Names Rubberwood, rubber tree, parawood, para rubber tree, heveawood, Malaysian oak, arbol de caucho, seringa, seringuera, capi, jeve, sapalapa, sibi-sibi, shiringa, white teak Height/Weight Plantation-grown trees average 60 to 80 feet in height, but trees can grow to 130 feet with trunks as wide as 12 feet in the wild. The weight averages 35 to 40 pounds per cubic foot, with a specific gravity of 0.46 to 0.52. Properties The wood air dries quickly, but care is needed to avoid problems with warping. Rubberwood should be dried under cover. Experts recommend a kiln schedule T6-D2 for 4/4 stock. The wood works well with hand or machine tools. The wood is moderately hard and stiff. It is similar in density to ash and maple. It needs preservative treatment for outdoor uses.

For years rubberwood’s most famous byproduct had little to do with the wood, but that has been changing. Rubberwood’s use for woodworking has been steadily increasing and the tree that was once burned for fuel after it was no longer suitable for tapping, is now valued for its use in a variety of wood components as well as dimension wood.

The wood is often fingerjointed and edge-glued to produce panels, then processed into various furniture parts. Tom Zenger of Holland Hardwoods in Holland, MI, imports parts made of rubberwood, also known as parawood, for eco-friendly home furnishings.

He and others stress the green story behind the species, which is often plantation grown. “The trees that would otherwise be cut down and burned after their use as latex producers is over, are now being used in a variety of furniture applications. We import components for our eco-friendly stools and finish them with a milk paint or other water-based stain,” Zenger said.

Usage Stretching

In addition to furniture and furniture components, rubberwood’s uses include: flooring, wood panels and indoor building components, particleboard and fiberboard, pulp and paper.

Doug Newhouse, president of Newhouse Wood & Veneer in West Hartford, CT, said rubberwood is not cut into veneer, because the plantation trees are never allowed to get big enough. “Even if they did get ‘big enough,’ the tree’s grain and texture are more suited to utility wood for furniture frames,” he said.

A report on rubberwood by Wulf Killman, director of the Forest Products Division, Food and Agriculture Organization, and Hong Lay Thong, also with Forest Research for the FAO, explores the rise of rubberwood as not only a valuable timber, but also one with a green story and affordable price tag.

“The inexpensive wood from plantation rubber trees, felled when they no longer yield adequate latex, is finding a market in high-value end products traditionally associated with more valuable hardwoods as teak,” said the authors of the study. However, although compared to teak in some respects, rubberwood has none of teak’s famous durability and is not suitable for boat production or exterior construction.

On the plus side, they said, rubberwood is available in large quantities, in part because of the trees’ “undemanding site requirements.”

Name Game

In addition to parawood, rubberwood has a long list of common names, including heveawood, para rubber, Malaysian oak and white teak — although its properties are not similar to oak or teak. Its characteristics have been compared to ramin.

In the book, The Illustrated Encyclopedia of Trees by Herbert Edlin and Maurice Nimmo, rubber trees are described as “a native of the Amazon forests in the Brazilian states of Para and Amazonas.” However, the editors note that the species has been planted on a large scale in several other countries hosting tropical climate areas. According to reports, more than 36 million acres of rubber trees are now being grown in Asia, Africa and America.

Newhouse said the wood is typically a pale cream to yellowish brown color often with a pink tinge. The wood’s tendency to discolor from oxidation can be checked via rapid production and vacuum drying.

Latex Legacy

Hevea brasiliensis is considered by many to be the most important member of the Euphorbiaceae family because its latex has been used in all parts of the world.

In the book, Know Your Woods, by Albert Constantine Jr., the structure of rubber tree bark is discussed for its importance, “because it contains the latex vessels which are the chief source of the world’s rubber supply.”

Constantine adds that the tree is widely believed to be the “purest and best source of para rubber.” According to Constantine, as early as 1834 Thomas Hancock, an English rubber manufacturer credited with discovering vulcanization, promoted the idea of growing Hevea brasiliensis in other parts of the world. “The hevea trees were established in Ceylon (now known as Sri Lanka) and many are now growing in plantations in Malaysia and the Dutch East Indies,” Constantine writes.

Rubber trees can be tapped in the fifth to seventh year after planting and continue to be a source of latex for 25 to 30 years. When the latex production slows to the point that the trees are no longer profitable, they are cut and new seedlings are planted.