Isoberlinia doka (doka)
Doka is a vigorously colonising African tree which often dominates the woodland belt that stretches from Guinea in the west to Uganda in the east.
About this species
Isoberlinia doka is a woodland tree which is common and widespread in west and central Africa, where it often dominates the landscape in uncultivated areas. This hardwood tree is quick to colonise clearings and abandoned land, and grows gregariously, often establishing near-pure stands. I. doka has been reported as a major food source for several species of silk-producing moths and is the principal host plant of the silk-producing moth Anaphe moloneyi (family Thaumetopoeidae). The use of silk moths in silk production is a sustainable industry that not only provides an income for local people, but also encourages the conservation of doka woodlands by rural communities.
Geography & Distribution
Native to west and central Africa, Isoberlinia doka is a major constituent of the woodland belt which stretches from Guinea in the west to Sudan and Uganda in the east. It also occurs extensively to the south of these woodlands, but in a more scattered manner, and is unknown south of the equator. I. doka occurs in Benin, Burkina Faso, Cameroon, Central African Republic, Chad, Côte D’Ivoire, Democratic Republic of the Congo (formerly Zaire), Ghana, Guinea, Mali, Niger, Nigeria, Sudan, Togo, and Uganda.
Isoberlinia doka is a tree measuring 10-20 m tall with a trunk of about 40-50 cm diameter, branching from about 5 m upwards. The leaflets are arranged in three or four pairs. The flowers are small and white, forming large open inflorescences that are held conspicuously above the leafy crown. The pods are oblong, flat and quite large, about 30 cm long and 10 cm wide. When they are mature, the two halves twist apart with such force that they can expel the seeds about 50 cm from the tree.
Threats & Conservation
Herbarium specimen of Isoberlinia doka collected in Nigeria by Dalziel, J.M. in 1911 (Image: RBG Kew)
Widespread in west and central Africa, Isoberlinia doka populations appear to be stable at present, and not unduly affected by harvesting for timber and other uses. However, the tree is known to be fire-sensitive, so any drying of the climate in the future may potentially pose a threat to some stands. There are no known conservation measures currently in operation specifically for I. doka, but it does grow in many protected areas. Samples of seed have been collected and are held in Kew’s Millennium Seed Bank as an ex situ conservation measure. It is recommended that further monitoring should be carried out to ensure this species is not over-exploited in the future.
Conservation assessments carried out by Kew
Isoberlinia doka is being monitored as part of the Sampled Red List Index Project, which aims to produce conservation assessments for a representative sample of the world’s plant species. This information will then be used to monitor trends in extinction risk and help focus conservation efforts where they are needed most.
Widely exploited for its timber in West Central Africa, Isoberlinia doka is used in carpentry and for making furniture, although the wood is somewhat difficult to work with hand-tools. It is also used as fuelwood. It is used for treating muscular-skeletal system disorders in traditional West African medicine. An infusion of the leaves is used for treating jaundice. Doka is also used to treat infectious diseases, and scientific investigations have confirmed its antibacterial activity. The tree is thought by some to have magical properties. It is potentially useful for land reclamation and reforestation schemes on account of its vigour, and ability to colonise clearings and abandoned land.
Millennium Seed Bank: Seed storage
Kew's Millennium Seed Bank Partnership aims to save plant life world wide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.
Number of seed collections stored in the Millennium Seed Bank: One.
This species at Kew
Dried and spirit-preserved specimens of Isoberlinia doka are held in the behind-the-scenes Herbarium at Kew, where they are available to researchers from around the world, by appointment. The details, including images, of some of these specimens can be seen on-line in the Herbarium Catalogue.
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