Common name: African teak

African teak is a major timber tree from the African continent. Its natural range extends from the humid forests of West Africa, east to the savannas of Ethiopia and south to Angola, Tanzania, Mozambique, and Zimbabwe.

In closely spaced forests in the wetter parts of its range, it may reach up to 45 m (150 ft), though elsewhere is more typically a small tree. The trunk is usually straight, sometimes with a slight buttress on large trees, free of branches for around half the tree height and supports a moderately branched rounded crown.

The leaves are elliptical, up to 15 cm (6 in) long and deep green. They are deciduous, falling off the tree in the dry season and leaving the branches bare until the rainy season when the new leaves start to grow.

The flowers are small and insignificant, greenish, borne on long, tail-like clusters and with female and male flowers on separate trees. They bloom in the dry season and are followed on female trees by small, green, elongated mulberry-like fruit.

Use

African teak produces a medium-weight wood, averaging around 620 kilograms per cubic meter (39 lbs per cubic ft), with good natural resistance to rot, decay and marine-boring insects. This puts it in the durable hardwood class, fit for indoor and outdoor construction, including underwater construction. The heartwood is coloured golden-orange to dark brown.

Well-formed logs are sawn into beams and planks used in heavy and light construction, including wharf and bridge construction, boat building, interior and exterior joinery, flooring, decking, as well as fine furniture and cabinets. 

Some logs are selected for slicing thinly into decorative veneer and plywood. Those too small in diameter are usually processed into particleboard.

Occasionally, stone-like calcium carbonate deposits, found embedded in the wood, dull the cutting blades and interrupt sawing or veneer cutting operations. 

The fruit is reportedly edible when ripe, but there is not much information on its attributes, such as taste, aroma, and texture.

African teak is heavily exploited for its wood. The International Union for Conservation of Nature (IUCN) listed it as a near-threatened species, bringing attention to its conservation need.

Climate

It grows naturally in humid tropical lowland climates, generally areas with annual lows of 18 to 25°C, annual highs of 27 to 35°C, annual rainfall of 1000 to 2500 mm and a dry season of 4 months or less. 

Although it also grows naturally in sub-humid savanna climates with annual rainfall of less than 1000 mm and a pronounced dry season, it develops a short trunk with a low-branching habit.

Growing

New plants are usually started from seed, which lose their viability quickly and should be sown soon after extracting them from the fruit. They can be stored under cold, dry, air-tight conditions for future use.

Seedling plants are ready for planting when around twelve to eighteen months old and perform best on rich, free-draining clay and loam soils of an acid to neutral nature, generally with a pH of 5.0 to 7.5, and on sites with full sun exposure. It has poor tolerance to slow-draining, saturated soils and shade conditions.

Problem features

There does not appear to be any records of escape and naturalisation anywhere in the world. Because of low fruit production, the short viability of the seed and the inability of seedlings to establish in the shade, it is unlikely to become a weed problem.

The wood is reported to cause contact dermatitis in carpenters and other woodworkers.

Books

• Brooks, Pamela 2001, The complete guide to allergies, Robinson, London

• C.A.B. International 2013, The CABI encyclopedia of forest trees, CABI Publishing, Wallingford, Oxfordshire

• Chudnoff, M. 1984, Tropical timbers of the world, Forest Service, U.S. Department of Agriculture (USDA), Washington, D.C.

• Crossman, M. & Simm, J. & Great Britain. Dept. of Trade and Industry & HR Wallingford (Firm) & Environment Agency (Great Britain) 2004, Manual on the use of timber in coastal and river engineering, Thomas Telford, London

• Food and Agriculture Organization of the United Nations (FAO) 1983, Food and Fruit-bearing Forest Species, 1 : Examples from Eastern Africa, FAO Forestry Paper no. 44/1, Rome

• Food and Agriculture Organization of the United Nations (FAO) 1986, Databook on endangered tree and shrub species and provenances, FAO Forestry Paper 77, Forest Resources Division, Rome

• Food and Agriculture Organization of the United Nations (FAO) 1986. Some medicinal forest plants of Africa and Latin America, Forest Resources Development Branch, Rome, Italy

• Forest Products Laboratory (U.S.) 2007, The encyclopedia of wood, Skyhorse Pub, New York

• Hines, D. A., & Eckman, K. 1993, Indigenous multipurpose trees of Tanzania: uses and economic benefits for people, Cultural Survival Canada

• Jacobson, M. 1958, Insecticides from plants : a review of the literature, United States Department of Agriculture (USDA), Washington D.C.

• Lemmens, R.H.M.J., Louppe, D. & Oteng-Amoako, A.A. (eds). PROTA, Plant Resources of Tropical Africa, Volume 7(1) : Timbers 1, PROTA Foundation, Backhuys Publishers, Leiden

• Martin, F. M., et al. 1987, Perennial edible fruits of the tropics : an inventory, U.S. Dept. of Agriculture (USDA), Agricultural Research Service, U.S. Government Printing Office (GPO), Washington, D.C.

• Martin, F. W & Ruberte, R. M. 1975, Edible leaves of the tropics, U.S. Agency for International Development (USAID), and the Agricultural Research Service, U.S. Department of Agriculture (USDA), Mayaguez, Puerto Rico

• Oliver, A. C & Timber Development Association 1974, Timber for marine and freshwater construction [Rev. ed.], Timber Research and Development Association (TRADA), High Wycombe, Bucks

• Porter, T. 2012, Wood : identification & use, Compact edition, Guild of Master Craftsman Publications, Lewes, East Sussex

• Scheffer, T. C & Morrell, J. J. 1998, Natural durability of wood : a worldwide checklist of species, Forest Research Laboratory, Oregon State University, Corvallis, Oregon

• Tatken, R. L., & C. A. Browning 1987, Health effects of exposure to wood dust: A summary of the literature. No. PB-87-218251/XAB, National Institute for Occupational Safety and Health, Cincinnati, Ohio

• Webb, D. B. 1984, A Guide to species selection for tropical and sub-tropical plantations, 2nd ed., Unit of Tropical Silviculture, Commonwealth Forestry Institute, University of Oxford, Oxfordshire

• Whitesell, C. D. & Walters, G. A. 1976, Species adaptability trials for man-made forests in Hawaii. Research Paper PSW-RP-118, U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station, Hawaii

Articles, Journals, Reports and Working Papers

• Joint FAO/ECE/ILO Committee on Forest Technology, Management, and Training. 2003. Harvesting of non-wood forest products: seminar proceedings. Ministry of Forestry of Turkey, Ankara.