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Iroko
(Chlorophora
excelsa)
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| Common
Names: |
|
African
Teak
Abang
Iroko
Kambala
Lusanga
Mandji
Mokongo
Molundu
|
Moreira
Mvule
Mvuli
Odum
Rokko
Semli
Tule mufala
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- Mechanical Values
| Category |
Green |
Dry |
Units |
| Weight |
58 |
49 |
lbs/cu.ft. |
| Density (air-dry) |
|
42 |
lbs/cu.ft. |
| Specific Gravity |
0.55 |
0.78 |
|
| Hardness |
|
1540 |
lbs |
| Stiffness |
1284 |
1763 |
1000 psi |
| Bending Strength |
10165 |
12730 |
psi |
| Shearing Strength |
|
1550 |
psi |
| Max. Crushing
Strength |
4915 |
8140 |
psi |
| Work to Maximum Load |
11 |
9 |
in-lbs/in3 |
| Radial Shrinkage
(G->OD) |
|
4 |
% |
| Tangential Shrink.
(G->OD) |
|
6 |
% |
| Volumetric Shrink
(G->OD) |
|
|
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- Environmental
Profile
This species is reported to be very secure within
most of its natural growth range, but is classified
as Vulnerable in Cameroon, Ivory Coast, Kenya, and
Zimbabwe. It has also been classified as Endangered
in Benin and Congo (Source - World Conservation
Monitoring Center - 1992).
Distributon
Chlorophora excelsa and C. regia are reported to be
distributed across the width of tropical Africa.
Iroko (C. excelsa ) is reported to be found
prinicipally in the Ivory Coast, Ghana, Nigeria, and
the Cameroons.
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 the species is a regular source of
timber. Timber export is regular except in the Ivory
Coast where exportation of the material in log form
is prohibited.
Iroko is reported to be available in moderate
quantities in long lengths, wide boards, and in the
form of veneers on the European market are priced in
the same range as the lower cost hardwoods.
Availability in the U.S. is rather limited, but
Iroko is reported to be sold at comparatively
inexpensive prices when available. Iroko is reported
to be substituted for Teak in many applications,
since it performs just as well as Teak and is less
expensive.
The following species in the database is reported to
have properties that are similar to those of Iroko:
Mandioquera (Qualea paraensis )
Tatajuba (Bagassa guianensis )
Tree Data
The tree is reported to attain heights of up to 160
feet (49 m) and trunk diameters of up to 120 inches
(300 cm). The boles are reported to be found
occasionally over small buttresses and are straight,
cylindrical, and clear to about 80 feet (24 m).
Sapwood Color
The sapwood is yellowish-white in color.
Heartwood Color
The heartwood is golden-orange to brown in color.
Lighter vessel lines are conspicuous on flat sawn
surfaces. Large deposits of calcium carbonate, with
darker colored surrounding material are usually
present. Yellow bands of soft tissue are reported to
form a zig-zag pattern on all surfaces.
Grain
The grain is moderately interlocked.
Texture
Texture is reported to be moderately coarse and
even.
Luster
Iroko is reported to be mildly lustrous.
Ease of Drying
The wood is reported to season rapidly and easily
with little or no degrade.
Drying Defects
Slight checking and distortion are reported to be
the only defects that may be encountered in drying.
Kiln Schedules
T6 - D2 (4/4) US; T3 - D1 (8/4) US
Movement in Service
Properly seasoned timber is reported to be
dimensionally stable, and retains its shape well
after manufacture.
T/R Ratio
1.50
This indicator is more meaningful if it is used
together with actual shrinkage data in the
tangential and radial directions. (Refer to the
Numerical Values window).
Natural Durability
The heartwood is reported to be naturally resistant
to decay, but is susceptible to attack by dry-wood
insects. The sapwood is susceptible to attack by
powder-post beetle, but has been reported to be
highly resistant to termite attack in Africa.
Resistance to Impregnation
The heartwood is reported to be highly resistant to
impregnation, but the natural durability of the wood
is reported to make preservative treatment
unnecessary in most cases.
Weathering Properties
The material is reported to possess adequate
weathering properties to allow it to be used in
exterior applications.
Resistance to Chemicals
Iroko is reported to be a good choice for making the
top of laboratory workbenches because of its high
resistance to chemical reagents.
Toxic Constituents
Wet sawdust has been associated with dermatitis in
some individuals.
Abnormal Wood Tissue
The timber may contain abnormal wood tissue in the
form of reaction wood.
Cutting Resistance
The wood has low resistance to sawing.
Blunting Effect
Occasional deposits of calcium carbonate can
severely and rapidly blunt cutting edges.
Planing
Machining properties such as planing, turning,
moulding, and boring are reported to be generally
good but variable. The material works fairly easily
with ordinary machine tools but there may be some
tearing in material with interlocked grain.
Occasional deposits of calcium carbonate can blunt
cutters severely and rapidly.
Gluing
The wood glues well, but casein glue is reported to
produce a black glue line.
Nailing
The material is reported to have good nailing
properties.
Screwing
The wood has satisfactory screwing properties.
Polishing
Iroko is reported to yield a high lustrous finish,
but it requires a fair amount of filling.
Staining
The wood is reported to stain well, after some
surface preparation.
Varnishing
The wood can be varnished satisfactorily, but it
requires some amount of filling or degreasing.
Painting
Painting properties are reported to be satisfactory,
but surface degreasing has been suggested for better
results.
Steam Bending
The wood is reported to have moderate steam bending
characteristics.
Response to Hand Tools
The material is reported to work satisfactorily with
hand tools, with a moderate to severe blunting
defect on cutting surfaces due to the presence of
calcareous stone deposits.
Strength Properties
Bending strength in the air-dry condition (about 12
percent moisture content) is high. Iroko is
comparable to Teak (Tectona grandis ) in most
strength properties, including hardness and
resistance to applied loads. Strength in compression
parallel to grain is in the high range. Hardness is
rated as medium. It resists denting and marring
about as well as white oak or birch. It is a very
heavy wood, and is high in density. Iroko is
reported to be used as an alternative to Teak in
many applications, although it is weaker in bending
and in compression along the grain.
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