wavy. The strength of air-dried merbau is comparable with
that of hickory (Carya), but density is somewhat lower
(800 kg m–3 (50 lb ft–3) at 12% moisture content). The
wood dries well with little degrade but stains black in the
presence of iron and moisture. Merbau is rather difficult to
saw because it sticks to saw teeth and dulls cutting edges.
However, the wood dresses smoothly in most operations
and finishes well. Merbau has good durability and high re-
sistance to termite attack. The heartwood resists treatment,
but the sapwood can be treated with preservatives. Merbau
is used in furniture, fine joinery, turnery, cabinets, flooring,
musical instruments, and specialty items.
Mersawa
Mersawa is one of the
common names applied
to the genus Anisoptera,
which has about 15 species
distributed from the Philip-
pine Islands and Malaysia
to east Pakistan. Names
applied to this wood vary
with the source, and three names are generally used in the
lumber trade: krabak (Thailand), mersawa (Malaysia), and
palosapis (Philippines).
Mersawa wood is light in color and has a moderately coarse
texture. Freshly sawn heartwood is pale yellow or yellow-
ish brown and darkens on exposure to air. Some wood may
show a pinkish cast or pink streaks, but these eventually
disappear on exposure to air. The wood weighs between
544 and 752 kg m–3 (34 and 47 lb ft–3) at 12% moisture
content and about 945 kg m–3 (59 lb ft–3) when green. The
sapwood is susceptible to attack by powderpost beetles, and
the heartwood is not resistant to termites. The heartwood is
rated as moderately resistant to fungal decay and should not
be used under conditions that favor decay. The heartwood
does not absorb preservative solutions readily. The wood
machines easily, but because of the presence of silica, the
wood severely dulls the cutting edges of ordinary tools and
is very hard on saws.
The major volume of mersawa is used as plywood because
conversion in this form presents considerably less difficulty
than does the production of lumber.
Mora
Mora (Mora excelsa and
M. gonggrijpii) is widely
distributed in the Guianas
and also occurs in the Ori-
noco Delta of Venezuela.
The yellowish red–brown,
reddish brown, or dark
red heartwood with palestreaks is distinct from the yellowish to pale brown sap-
wood. The texture is moderately fine to rather coarse, and
the grain is straight to interlocked. Mora is a strong and
heavy wood (density of air-dried wood is 945 to 1,040 kg
m–3 (59 to 65 lb ft–3)); this wood is moderately difficult to
work but yields smooth surfaces in sawing, planing, turn-
ing, and boring. The wood is generally rated as moderately
difficult to dry. Mora is rated as durable to very durable in
resistance to brown- and white-rot fungi. M. gonggrijpii is
rated very resistant to dry-wood termites, but M. excelsa is
considerably less resistant. The sapwood responds readily
to preservative treatments, but the heartwood resists
treatment.
Mora is used for industrial flooring, railroad crossties,
shipbuilding, and heavy construction.
Oak (Tropical)
The oaks (Quercus) are
abundantly represented in
Mexico and Central Amer-
ica with about 150 species,
which are nearly equally
divided between the red
and white oak groups.
More than 100 species
occur in Mexico and about 25 in Guatemala; the number
diminishes southward to Colombia, which has two species.
The usual Spanish name applied to the oaks is encino or
roble, and both names are used interchangeably irrespective
of species or use of the wood.
In heartwood color, texture, and grain characteristics, tropi-
cal oaks are similar to the diffuse porous oaks of the United
States, especially live oak (Quercus virginiana). In most
cases, tropical oaks are heavier (density of air-dried wood
is 704 to 993 kg m–3 (44 to 62 lb ft–3)) than the U.S. spe-
cies. Strength data are available for only four species, and
the values fall between those of white oak (Q. alba) and
live oak (Q. virginiana) or are equal to those of live oak.
The heartwood is rated as very resistant to decay fungi
and difficult to treat with preservatives.
Utilization of the tropical oaks is very limited at present be-
cause of difficulties encountered in the drying of the wood.
The major volume is used in the form of charcoal, but the
wood is used for flooring, railroad crossties, mine timbers,
tight cooperage, boat and ship construction, and decorative
veneers.
Obeche
Obeche (Triplochiton scleroxylon) trees of west-central Af-
rica reach a height of 50 m (150 ft) or more and a diameter
of up to 2 m (5 ft). The trunk is usually free of branches for
a considerable height so that clear lumber of considerable
size can be obtained.Chapter 2 Characteristics and Availability of Commercially Important Woods