Biology
provided by Arkive
Okoumé is a light-demanding species which requires full sun to grow well (2) (3), and as a pioneer species it readily colonises open spaces (2) (5). New leaves appear from September to December and are bright red for about a week. Flowering usually starts at the end of the dry season, in August, and may last up to two months, although individual flowers last for only a few days. The whitish flowers, which are insect-pollinated, are borne on branched inflorescences up to 20 centimetres long, with male and female flowers borne on separate trees. Although okoumé may begin to flower at about ten years old, it only starts to produce fruit after about fifteen years, or when the tree has reached 30 to 40 centimetres in diameter. After this, fruiting is usually annual, taking place between January and March, though large quantities of seeds are only produced every few years. The fruits comprise capsules up to five centimetres by three centimetres in size, each producing five spoon-shaped, winged seeds, which are dispersed by the wind up to 200 metres from the parent tree (2) (5). A mature okoumé tree may produce up to 20,000 seeds (2). Okoumé is a long-living tree, with individuals sometimes reaching up to 300 years old (5).
Okoumé produces a lightweight, relatively soft hardwood, which is considered excellent for veneer and plywood, and is also used in light construction and furniture (2) (3) (5). In Gabon and Equatorial Guinea, it is also used as firewood and for building dugout canoes, and the bark resin is used for torches and oil lamps. The bark itself may be used to treat wounds and abscesses and as a treatment for diarrhoea (2) (5).
Conservation
provided by Arkive
Okoumé is considered a priority species for in situ conservation programmes (3) in order to protect its population long-term. Although it has been grown in plantations since 1944, only a small proportion of timber felled in natural forests has been replaced by plantation development (4). It has been suggested that the species should be listed on Appendix II of the Convention on International Trade in Endangered Species in Equatorial Guinea and the Republic of Congo, meaning international trade in the species should be carefully controlled in these states, and on Appendix III in Gabon, allowing a certain amount of controlled trade (7), although this has yet to be agreed.
Description
provided by Arkive
This medium- to large-sized evergreen is Gabon's most important commercial tree, contributing around 90 percent of the country's total timber production (1) (3) (4). The trunk of okoumé is cylindrical and clear of branches up to about 21 metres, with wing-like buttresses up to about three metres high, in individuals over 30 to 40 centimetres in diameter. The smooth bark is greyish to orange-brown in colour, and lichens growing on young trees may result in spotting with white, yellow, orange or red bands. In older trees, the bark cracks and sheds in large vertical scales (2) (5). The heartwood is salmon-pink, and the narrow sapwood whitish or pale grey (5) (6). The leaves of okoumé are alternate and pinnate, bearing between 7 and 13 leaflets, which are ovate to oblong in shape and leathery in texture, with entire (unserrated) edges (2).
Habitat
provided by Arkive
Lowland broadleaf forests up to elevations of 700 to 1,000 metres (3) (5). Okoumé grows well on a wide range of acid soils (2) (5), and is common in secondary forest (3), though it is generally absent from flooded areas (5).
Range
provided by Arkive
The natural range of okoumé is restricted to western and central Gabon and areas of Equatorial Guinea, Republic of Congo and Cameroon (1) (3). The species has also been introduced to Madagascar, Ivory Coast, Ghana, Central African Republic, French Guiana, Indonesia, Malaysia and Surinam (2) (5).
Status
provided by Arkive
Classified as Vulnerable (VU) on the IUCN Red List (1).
Threats
provided by Arkive
Okoumé regenerates naturally when sufficient periods are left between logging cycles (2). However, repeated logging restricts regeneration and while some consider logging to be sustainable in Gabon, other fear for the long-term survival of this species (1) (3). There is also concern that repeated, selective felling of okoumé may be leading to deterioration of the gene pool in some areas (1) (3) (4). Some predict that okoumé forest will probably be exhausted in Equatorial Guinea and the Republic of Congo in the near future (7), and although the species remains abundant in Gabon, it appears logging restrictions, such as minimum logging diameters, are not always enforced (3).
Aucoumea klaineana
provided by wikipedia EN
Aucoumea klaineana (angouma, gaboon, or okoumé) is a tree in the family Burseraceae, native to equatorial west Africa in Gabon, the Republic of the Congo, and Río Muni. It is a large hardwood tree growing to 30–40 m (100–130 feet) tall, rarely larger, with a trunk 1.0–2.5 m (3.5–8 feet) diameter above the often large basal buttresses. The tree generally grows in small stands, with the roots of the trees intertwined with neighboring trees. In Gabon, it is the primary timber species.
Uses
It is a weak wood, with low decay resistance and moderate dimensional stability. The major use of gaboon is in the manufacture of plywood. It is about 8–12% lighter than the other main marine plywood, meranti, that is commonly used in boatbuilding, but is not as stiff. This is useful when a boat design calls for tight-radius bends, such as near the bow in a single chine design, because of its flexibility. However, it does not resist impact damage as well as meranti. It is often sheathed in epoxy resin to increase strength and give more impact and abrasion resistance, and to increase water resistance over conventional marine enamel paints. It is often used in sandwich construction using the West (and other similar) epoxy system.
Its attractive appearance means that it is often used decoratively as the top surface veneer in panelling and furniture, or in solid form, in luxury items such as boxes for cigars or other high-value items (e.g. audio equipment).
Gaboon plywood is also used in the French aircraft industry to make light airplanes, such as those built by Avions Robin. It was used extensively to manufacture the Jodel range of aircraft, which are popular throughout Europe, but no longer factory-built. However, the wood's open grain, flexibility, and light weight make it a popular choice for amateur builders of Jodel aircraft to this day.
In the form known as okoumé marine-grade plywood, it is considered perhaps the finest construction plywood now available for boats, especially where lighter weight is needed. It is widely available manufactured and certified to British Standard 1088. Its users range from individual hobbyist kayak builders to some of the world's largest boat builders. Most often it is used in combination with epoxy and fiberglass, the combination giving a structure that can be stronger and lighter than plastic or fiberglass, rivaling the performance characteristics of more advanced composites such as carbon fiber. The grain appearance is prized, likened to that of mahogany, and is often varnished for a decorative appearance.
When used for the backs and sides of high-end acoustic guitars, okoumé (or as it is known in the trade, akoumé) exhibits many of the tonal properties of maple. Guitars made with okoumé are noticeably lighter in weight than those made with mahogany or rosewood.
References
- license
- cc-by-sa-3.0
- copyright
- Wikipedia authors and editors
Aucoumea klaineana: Brief Summary
provided by wikipedia EN
Aucoumea klaineana (angouma, gaboon, or okoumé) is a tree in the family Burseraceae, native to equatorial west Africa in Gabon, the Republic of the Congo, and Río Muni. It is a large hardwood tree growing to 30–40 m (100–130 feet) tall, rarely larger, with a trunk 1.0–2.5 m (3.5–8 feet) diameter above the often large basal buttresses. The tree generally grows in small stands, with the roots of the trees intertwined with neighboring trees. In Gabon, it is the primary timber species.
- license
- cc-by-sa-3.0
- copyright
- Wikipedia authors and editors
