Wood Handbook, Wood as an Engineering Material

Balau

Balau, red balau, and se-

langan batu constitute a

group of species that

are the heaviest of the

200 Shorea species. About

45 species of this group

grow from Sri Lanka and

southern India through

southeast Asia to the

Philippines.

The heartwood is light to deep red or purple–brown, and

it is fairly distinct from the lighter and yellowish- to red-

dish- or purplish-brown sapwood. The texture is moderately

fine to coarse, and the grain is often interlocked. The wood

weighs more than 750 kg m–3 (47 lb ft–3) at 12% moisture

content. Balau is a heavy, hard, and strong timber that dries

slowly with moderate to severe end checks and splits. The

heartwood is durable to moderately durable and very resis-

tant to preservative treatments.

Balau is used for heavy construction, frames of boats, deck-

ing, flooring, and utility furniture.

Balau, Red

(see Balau)

Balsa

Balsa (Ochroma pyrami‑

dale) is widely distributed

throughout tropical Amer-

ica from southern Mexico

to southern Brazil and

Bolivia, but Ecuador has

been the principal source

of supply since the wood

gained commercial im-

portance. It is usually found at lower elevations, especially

on bottom-land soils along streams and in clearings and

cutover forests. Today, it is often cultivated in plantations.

Several characteristics make balsa suitable for a wide vari-

ety of uses. It is the lightest and softest of all woods on the

market. The lumber selected for use in the United States

weighs, on the average, about 180 kg m–3 (11 lb ft–3) when

dry and often as little as 100 kg m–3 (6 lb ft–3). The wood

is readily recognized by its light weight; nearly white or

oatmeal color, often with a yellowish or pinkish hue; and

unique velvety feel.

Because of its light weight and exceedingly porous com-

position, balsa is highly efficient in uses where buoyancy,

insulation against heat or cold, or low propagation of sound

and vibration are important. Principal uses are for life-

saving equipment, floats, rafts, corestock, insulation,

cushioning, sound modifiers, models, and novelties.

Banak, Cuangare

Various species of banak

(Virola) occur in tropical

America, from Belize

and Guatemala south-

ward to Venezuela, the

Guianas, the Amazon

region of northern Bra-

zil, and southern Brazil,

and on the Pacific Coast

to Peru and Bolivia. Most of the wood known as banak is

V. koschnyi of Central America and V. surinamensis and

V. sebifera of northern South America. Botanically, cuan-

gare (Dialyanthera) is closely related to banak, and the

woods are so similar that they are generally mixed in the

trade. The main commercial supply of cuangare comes from

Colombia and Ecuador. Banak and cuangare are common

in swamp and marsh forests and may occur in almost pure

stands in some areas.

The heartwood of both banak and cuangare is usually pink-

ish or grayish brown and is generally not differentiated

from the sapwood. The wood is straight grained and is of

a medium to coarse texture. The various species are nonre-

sistant to decay and insect attack but can be readily treated

with preservatives. Machining properties are very good, but

when zones of tension wood are present, machining may

result in surface fuzziness. The wood finishes readily and is

easily glued. Strength properties of banak and cuangare are

similar to those of yellow-poplar (Liriodendron tulipifera).

Banak is considered a general utility wood for lumber, ve-

neer, and plywood. It is also used for moulding, millwork,

and furniture components.

Benge, Ehie, Bubinga

Although benge (Gui‑

bourtia arnoldiana), ehie

(or ovangkol) (Guibourtia

ehie), and bubinga (Gui‑

bourtia spp.) belong to the

same West African genus,

they differ rather marked-

ly in color and somewhat

in texture.

The heartwood of benge is pale yellowish brown to medium

brown with gray to almost black stripes. Ehie heartwood

tends to be more golden brown to dark brown with gray to

almost black stripes. Bubinga heartwood is pink, vivid red,

or red–brown with purple streaks, and it becomes yellow or

medium brown with a reddish tint upon exposure to air. The

texture of ehie is moderately coarse, whereas that of benge

and bubinga is fine to moderately fine. All three woods are

moderately hard and heavy, but they can be worked well

with hand and machine tools. They are listed as moderately

Chapter 2 Characteristics and Availability of Commercially Important Woods