BOTANICAL NAME: Mainly Milicia excelsa, with lots of synonyms including Chlorophora exelsa, Chlorophora alba, Chlorophora tenuifolia, Maclura excelsa, Milicia africana, and Morus excelsaf. So much for the uniqueness of botanical names. Milicia regia is also sometimes called iroko.
COMMON NAMES: Iroko has many of the same uses of teak and is sometimes used as a teak substitute. While the tree is not related to the "true" teak, Tectona grandis, it has sometimes been called African teak or Nigerian teak. Other common names include: abang, african oak, african teak, agui, akede, bakana, band, bang (cameroons), banghi, bobang, bonzo, bush oak, bush teak, bwagashanga, cambala, corkwood, elowa, elua, elui, emang, framere, geh, guele, guh, gutumba, intule (mozambique), ireme, kambala, kambala (zaire), kimurumba, logo asagu, loko, lusanga, mamangi, mandji (cameroon and gabon), mbala, mbara, mereira (angola), mgunda, minarui, mokongo, moloundou, molundu, moreira (angola), muberry, mucoco, mufala, murie, murumba, mururi, mutumba, mutumbav, muvule, mvule (east africa), mvuli, mvulu, myule, nsan, ntong, obas tree, odji, odoum (ghana and ivory coast), odum (ghana and ivory coast), oduna, ofryio, olia, olua, olwaa, oroko (nigeria), oroko ulokoodigpe, rock elm, roco, rokko, sanga, semei, semli (sierra leone and liberia), sili, sime, simli, simme, ssare, teak, tema, timmi, tomboiro noir, toumbohiro noir, tule, tule mufala, uklobce, ulok, uloko-mushinogbon, ulundu, vai
COLOR: When freshly cut, or when unexposed to light, the heartwood is a distinct yellow colour, but on exposure to light it quickly becomes golden-brown to dark chocolate brown. Although it darkens in indirect sunlight, it bleaches in direct sunlight. Lighter vessel lines are conspicuous on flat sawn surfaces. Yellow bands of soft tissue are reported to form a zig-zag pattern on all surfaces. Sapwood is generally a few inches thick, yellowish white, and well demarcated from the heartwood.
GRAIN: The grain is usually interlocked and sometimes irregular. Lighter markings are associated with vessel lines on flatsawn surfaces, while quartersawn surfaces usually have a widely spaced striped figure.
TEXTURE: medium to coarse, but even and sometimes with a slightly greasy feel
PROPERTIES / WORKABILITY: It is easy to work and cut with both hand and machine tools, but Occasional deposits of calcium carbonate can severely and rapidly blunt cutting edges and there may be some tearing in material with interlocked grain. Gum deposits are also widely reported as a potential problem. It takes nails and screws well, sands well, glues well (but casein glue is reported to produce a black glue line). On quarter-sawn stock, there is a tendency for grain to pick up due to interlocked grain, and a reduced cutting angle is usually necessary to obtain a smooth surface.
DURABILITY: The heartwood is resistant to decay and is resistant to termite and marine borer attackbut susceptible to attack by dry-wood insects. The sapwood is liable to powder-post beetle attack, but it is resistant to termite attack in Africa. The heartwood is extremely resistant to preservative treatment. The sapwood is permeable.
mechanically, it is quite durable which is one of several reasons why it is frequently mentioned as a good substitute for teak. Also, it is reported to possess adequate weathering properties to allow it to be used in exterior applications.
FINISH: reported to stain, varnish, paint and generally finish quite well, but some surface preparation is frequrently called for (filling and/or degreasing). Polishes to a moderately high luster, but again, filling is generally required
STABILITY: movement in service is usually rated as small, but occasional reports indicate medium movement
BENDING: moderate steam-bending properties; not recommended for bent work
ODOR: none reported
SOURCES: The two species, between them, extend across the entire width of tropical Africa. C. regia is limited to the extreme west of Africa from Gambia to Ghana and is less drought resistant and C. excelsa is found almost everywhere across the width of tropical Africa. Together the occur in at least all of the following countries: Angola, Benin, Burundi, Cameroon, Congo, Côte d'Ivoire, East Africa, Gabon, Gambia, Ghana, Guinea, Guinea-bissau, Ivory Coast, Kenya, Liberia, Mozambique, Nigeria, Rwanda, Senegal, Sierra Leone, Tanzania, Togo, Uganda, Zaire, and Zimbabwe
USES: Iroko is reported to be a good choice for making the top of laboratory workbenches because of its high resistance to chemical reagents, and its general properties make it a good substitute anywhere that teak is normally used. Its good weathering properties allow its use in exterior applications. It is also used for: agricultural implements, boat building (general - decking - framing - planking), boxes and crates, bridge construction, building materials, cabinet work, canoes, carving, chairs, chests, coachwork, concealed parts (furniture), cooperages, core stock, counter and table tops, decks, decorative veneer, desks, dining-room furniture, domestic flooring, doors, dowell pins, drawer sides, exterior and interior joinery, factory flooring, figured veneer, fine furniture, fire-proof doors, floor lamps, flooring, framing, furniture components, garden and park benches, golf club heads, hatracks, heavy construction, interior and exterior joinery, interior construction, interior trim, joinery, joinery (external): ground contact, kitchen cabinets, laboratory benches, lifeboats, light construction, light flooring, living-room suites, lock gates, marine uses such as pilings and docks, millwork, mine timbers, moldings, musical instruments: percussion, office furniture, paneling, parquet flooring, particleboard, plywood and veneer, posts, pulp/paper products, radio, radio - stereo - tv cabinets, railroad crossties, railroad ties, rustic furniture, shingles, ship and boat building, shop fittings, sills, stair rails, stair treads, stairworks, stereo, stools, stringers, structural timber, sub-flooring, tables, trimming, turnery, tv cabinets, utility furniture, vats, vehicle parts, veneer, wainscotting, wardrobes, wheel spokes, wheels, window frames
TREE: heights reach 160 ft, bole straight, trunk diameter to 8 or 9 feet (4 or 5 more common), cylindrical and clear to 80 ft, small buttresses sometimes present
WEIGHT: 45 pounds per cubic foot, give or take about 5
DRYING: dries easily and quickly, usually with little to no degrade of any kind (occasional slight end splitting and/or distortion). Because of light sensitivity, it may develop discoloration from stickers.
AVAILABILITY: moderate to limited
OTHER NOTES: Many reports note the high occurance of reaction wood (which tends to promote excessive differential shrinkage and machining difficulties) and many reports also note that wet sawdust may cause dermatitis and fine machining dust can irritate skin and nasal passages, and is especially dangerous to workers with asthma.
- - - - - - - - - - - - - -
A Good Teak Substitute: Iroko, according to The Encyclopedia of Wood, "lacks the greasy feel of teak" yet it has enough similarities to make a good substitute. Iroko is harder but slightly weaker than teak. Among the uses they share are garden and park bench seats. It is also used for counters and laboratory bench tops and draining boards, because of its durability in wet conditions. Albert Constantine, Jr., in the book Know Your Woods, writes that quartered iroko is used for furniture and architectural panels.
- - - - - - - - - - - - - -
The following statement is typical of several reports: "Large, hard deposits of calcium carbonate called 'stone deposits, are sometimes present in cavities, probably as a result of injury to the tree. They are often enclosed by the wood and not visible until the time of sawing, though the wood around them may be darker in colour, thus giving an indication of their presence."
- - - - - - - - - - - - - -
One quirky thing about the tree is what happens after cutting. When freshly cut, the stump oozes a clear resin that covers the cut area and hardens, forming a glass-like surface that retards decay.
- - - - - - - - - - - - - -