Iroko

Wikipedia SV

Iroko, Chlorophora excelsa, samt Chlorophora regina, är ett hårt gulbrunt träslag från Afrika som har kommit till användning som ersättning till den dyrare teaken till vissa ändamål. Iroko lämpar sig väl till båtvirke och även till kölar.

Wikipedia EN

Iroko (also known as ọ́jị̀ in Igbo language, 'uloho' in the Urhobo language of Southern Nigeria, and as odum in the Kwa languages of Ghana) is a large hardwood tree from the west coast of tropical Africa that can live up to 500 years. This is the common name for the genus Milicia, in which there are two recognized species, which are closely related: Milicia excelsa and Milicia regia.

The genus name of Milicia is in honour of Milici (19th and 20th centuries), an administrator in Portuguese East Africa (in modern-day Mozambique) who supported the work of the author of the genus, Thomas Robertson Sim. It was first described and published in Forest Fl. Port. E. Afr. on page 97 in 1909.

The tree is known to the Yoruba as ìrókò, logo or loko and is believed to have healing properties.[6] Iroko is known to the Igbo people as ọjị wood. It is one of the woods sometimes referred to as African teak, although it is unrelated to the teak family. The wood colour is initially yellow but darkens to a richer copper brown over time.
Contents

Species

Iroko is yielded mostly (probably) by Milicia excelsa. In much of the literature on this timber the names of the trees that yields it are given as Chlorophora excelsa (syn. Milicia excelsa) and Chlorophora regia (syn. Milicia regia).

Milicia excelsa is currently listed as 'lower risk/near threatened' on the IUCN Red List.

Both species are dioecious, with male and female flowers on separate individuals.

Uses

The timber is used for a variety of external and internal purposes including boat-building, domestic flooring, furniture and outdoor gates. From the late 1990s, it was used as part of the txalaparta, a Basque musical instrument constructed of wooden boards, due to its lively sound. Iroko is one of the traditional djembe woods. Iroko wood was the wood chosen for the pews in the Our Lady of Peace Basilica.

It is a very durable wood; iroko does not require regular treatment with oil or varnish when used outdoors, although it is very difficult to work with tools as it tends to splinter easily, and blunts tools very quickly.

In the UK there are no trade restrictions on the machining of this timber. The only reported adverse effects known to be caused by the dust from iroko are asthma, dermatitis and nettle rash.

Cultural beliefs

The tree is feared in some cultures where it originates and hence is shunned or revered with offerings. Yoruba people believe that the tree is inhabited by a spirit, and anybody who sees the Iroko-man face to face becomes insane and speedily dies. According to the Yoruba, any man who cuts down any iroko tree causes devastating misfortune on himself and all of his family, although if they need to cut down the tree they can make a prayer afterwards to protect themselves.

They also claim that the spirit of the Iroko can be heard in houses which use iroko wood, as the spirit of the Iroko is trapped in the wood. In Nigeria the iroko wood is of much lower quality due to soil conditions as well as root-rot. Some Westerners refer to the wood as “poor man's teak”.

Cultural beliefs

The tree is feared in some cultures where it originates and hence is shunned or revered with offerings. Yoruba people believe that the tree is inhabited by a spirit, and anybody who sees the Iroko-man face to face becomes insane and speedily dies. According to the Yoruba, any man who cuts down any iroko tree causes devastating misfortune on himself and all of his family, although if they need to cut down the tree they can make a prayer afterwards to protect themselves.

They also claim that the spirit of the Iroko can be heard in houses which use iroko wood, as the spirit of the Iroko is trapped in the wood. In Nigeria the iroko wood is of much lower quality due to soil conditions as well as root-rot. Some Westerners refer to the wood as “poor man's teak”.

Wood database

Color/Appearance: Heartwood is usually a yellow to golden or medium brown, with color tending to darken over time. Pale yellow sapwood is clearly demarcated from the heartwood.

Grain/Texture: Iroko has a medium to coarse texture, with open pores and an interlocked grain.

Endgrain: Diffuse-porous; large to very large pores in no specific arrangement, very few to few; solitary and radial multiples of 2-3; tyloses common; growth rings indistinct; medium rays visible without lens, spacing wide to normal; parenchyma banded, paratracheal parenchyma vasicentric, aliform (winged and lozenge), and confluent.

Rot Resistance: Iroko is very durable, and is resistant to both rot and insect attack; it’s sometimes used as a substitute for Teak.

Workability: Generally easy to work, with the exception of its interlocked grain, which may cause some tearout during surfacing operations. Also, deposits of calcium carbonate are sometimes present, which can have a significant dulling effect on cutters. Iroko glues and finishes well.

Odor: No characteristic odor.

Allergies/Toxicity: Although severe reactions are quite uncommon, Iroko has been reported as a sensitizer. Usually most common reactions simply include eye, skin, and respiratory irritation. Iroko can also cause other health effects in sensitive individuals, such as asthma-like symptoms, boils, and hypersensitivity pneumonitis. See the articles Wood Allergies and Toxicity and Wood Dust Safety for more information.

Sustainability: This wood species is not listed in the CITES Appendices, but is on the IUCN Red List. It is listed as vulnerable due to a population reduction of over 20% in the past three generations, caused by a decline in its natural range, and exploitation.

Common Uses: Veneer, flooring, furniture, cabinetry, boatbuilding, turned items, and other small specialty wood items.