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Zebrawood
(Microberlinia
brazzavillensis)
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| Common
Names: |
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African
zebrawood
Allen ele
Zebrano
Zingana
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- Mechanical Values
| Category |
Green |
Dry |
Units |
| Weight |
|
46 |
lbs/cu.ft. |
| Density (air-dry) |
|
53 |
lbs/cu.ft. |
| Specific Gravity |
0.70 |
0.74 |
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| Hardness |
|
|
|
| Stiffness |
1550 |
1800 |
1000 psi |
| Bending Strength |
9000 |
13900 |
psi |
| Shearing Strength |
|
1900 |
psi |
| Max. Crushing
Strength |
4500 |
7750 |
psi |
| Work to Maximum Load |
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| Radial Shrinkage
(G->OD) |
|
7 |
% |
| Tangential Shrink.
(G->OD) |
|
12 |
% |
| Volumetric Shrink
(G->OD) |
|
17 |
% |
- Environmental
Profile
This species is reported to be relatively abundant,
with little or no threat to its population within
its natural growth range (Source - World
Conservation Monitoring Center - 1992 ).
Distribution
The species is reported to be distributed in West
Africa, especially in Gabon and Cameroon. It is
sometimes found in pure stands along river banks,
but growing sites are reported to be often quite
inaccessible.
Product Sources
Some material from this species is reported to be
available from sustainably managed or other
environmentally responsible sources.
The International Tropical Timber Organization (ITTO)
reports that timber from this species is produced in
regular but limited quantities and exported
regularly.
The trees are reported to be difficult to harvest
because they can grow to very large sizes and are
often located in inaccessible areas. Harvesting
difficulties and the need for quarter sawing,
instead of the more economical plain sawing, are
reported to add to the overall cost of the timber.
Zebrawood is reported to be moderately expensive,
and is available in limited quantities since its use
is limited. Almost all the zebrawood sold on the
market is reported to be quarter-cut. Veneers are
also reported to be quarter-sliced to produce a
straight grain, straight lined appearance, because
plain-slicing is reported to produce a wild and
unappealing appearance.
The following species in the database is reported to
be similar in properties to Zebrano:
Muiracataria (Astronium leicointei )
Tree Data
Trunk diameters are reported to be about 48 to 60
inches (120 to 150 cm). The trees usually have very
thick barks, which are removed at felling sites.
Sapwood Color
The sapwood is whiish in color.
Heartwood Color
The heartwood is light golden-yellow or pale
yellow-brown in color, with narrow-veining or
streaks of dark brown to almost black, giving a
zebra-stripe appearance.
Grain
The grain is usually interlocked or wavy, which
yields a ribbon figure.
Texture
The texture is typically medium to coarse.
Luster
The wood is reported to have a high luster.
Odor
Green wood has an odor that has been characterized
as unpleasant. The odor disappears after drying.
Resin Content
The wood is reported to occasionally contain resin
pockets.
Ease of Drying
The wood is reported to be fairly difficult to dry,
but it responds well to air-seasoning.
Drying Defects
Surface checking, splitting, and distortion may
develop without careful seasoning.
Kiln Schedules
T2 - C2 (4/4); T2 - C1 (8/4) US
Movement in Service
The timber is reported to be dimensionally stable
after seasoning, and retains its shape well after
manufacture.
T/R Ratio
1.69
This indicator is more meaningful if it is used
together with other drying information and actual
shrinkage data in the tangential and radial
directions. (Refer to the Numerical Values window).
Natural Durability
The wood is reported to be resistant to termites,
but is susceptible to occasional pinhole borer
attack.
Resistance to Impregnation
The heartwood is reported to be highly resistant to
preservative treatment. The sapwood is treatable.
Veneering Qualities
The best quality veneers are reported to come from
quarter sliced material. Zebrawood is reported to be
used extensively in the veneer form for cross
banding and inlays. Bundles of veneer should be
stabilized with weights to prevent buckling.
Blunting Effect
The wood exerts slight to moderate blunting effect
on cutting tools.
Cutting Resistance
The material is reported to be very easy to saw but
cross-cutting may produce rough surfaces. It is
reported to saw easily in the seasoned contion.
Large trees are reported to often suffer damage in
the form internal fractures which remain hidden
until logs are processed.
Planing
Planing is reported to be rather difficult. Material
containing interlocked grain may tear badly, but
torn surfaces can be smoothed by sanding.
Turning
The wood is reported to work well in most machining
operations including, turning, boring, moulding,
mortising, and routing. It responds well to most
ordinary tools, with moderate dulling of cutting
edges. Torn surfaces are reported to be a common
machining defect in material with interlocked grain.
Gluing
The wood is reported to have good gluing properties,
but may need filling.
Sanding
The wood has good sanding properties and the
operation is is reported to be often required to
clean fuzzy surfaces produced from other machining
operations. The use of a belt sander has been
recommended.
Polishing
The wood has good finishing and polishing
characteristics.
Varnishing
Varnishing characteristics are reported to be good.
Response to Hand Tools
The material responds well to hand tools.
Strength Properties
Bending strength of air-dried wood is similar to
that of Teak, which is considered to be strong.
Compression strength parallel to grain in the
air-dry condition is high. Zebrano timber is
reported to be fairly hard, very heavy, very dense,
with good toughness and impact properties. Although
it is strong, its uses usually do not require great
strength.
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