Irvingia gabonensis

Irvingia gabonensis is indigenous to the humid forest zone from the northern tip of Angola, including Congo, DR Congo, Nigeria, Ivory Coast and south-western Uganda.[2][3] Since 2009, the Gabonese government has prohibited logging of the andok tree until 2034.[4]

Irvingia gabonensis grows straight, up to a height of 40 m (130 ft) and 1 m (3 ft 3 in) in diameter.[2] It has buttresses to a height of 3m (10 ft). The outer bark is smooth to scaly with grey to yellow-grey color. The crown is evergreen, spherical and dense. Leaves are elliptic, one margin is often a little rounder than the other, acuminate, dark green and glossy on the upper surface. Flowers are yellow to greenish-white in small panicles.[2] The flowers are bisexual. The fruit is nearly spherical, green when ripe with a bright orange pulp. The stone is woody and contains one seed. Seeds germinate epigeally (above ground).[2]

Irvingia gabonensis is insect-pollinated by Coleoptera, Diptera, Hymenoptera and Lepidoptera.[2] It flowers from March to June and has two fruiting seasons: from April to July and from September to October.[3] Seeds are dispersed by vertebrates, including elephants and gorillas. With a reduction in the number of those animals, the spread and regeneration of African bush mango decreases and it becomes more dependent on human planting.[6]

In the past, 90% of African bush mango products were harvested from scattered, wild trees.[3] African bush mango trees were not cultivated initially, because it was believed, that it took up to 15 years for a tree to bear fruit. Although they were not artificially planted, their occurrence was high because they were also rarely harvested for timber. In a plantation using marcots (air-layering plants), flower production was observed within two to four years after planting.[3] Germination from seeds is low and when they are not handled appropriately, most fail.[3] The seeds are mostly extracted by breaking fruits by hand.[3]

The fruits are often eaten fresh by humans and other mammals such as monkeys, gorillas, elephants and many more. As it is naturally and predominantly found in parts of Africa, it has been popularly called African mango.[2] The fruits are processed into jelly, jam, juice and sometimes even wine.[5] The pulp has also been used to prepare black dye for cloth coloration.

The seed coat has to be cracked open to get to the endosperm. Seeds, also called dika nuts, are eaten raw or roasted. Mostly however they are pounded to butter- or a chocolate-like block.[6] Seeds can be pressed to produce an edible oil (solid at ambient temperatures) or margarine used for cooking. The oil can also be processed further to soap or cosmetics.[6] The press cake can be used as cattle feed or as thickening agent for soup. Seeds can be ground or crushed and used as a thickening and flavoring agent in soups and stews.[2] They can also be made into a cake called "dika bread" for preservation.[2]

Dika bread

The nuts are often used in the Gabonese cuisine to season poultry and meat dishes, such as the poulet à l'odika. The ground nuts provide a smoked scent to the meals.

The wood is hard and therefore used for heavy construction work as making ships' decks or railway ties.[2] Dead branches are used as firewood.[6]

The trees are used in agroforestry systems to shade other crops, especially cocoa and coffee. They are also used to reduce erosion. Cities have started using them to shade streets, as shelter belts, or for beautification.

Thousands of tons of African bush mango seeds are traded each year, mostly within Africa.[7]

• "Irvingia gabonensis". Forest Products Laboratory Tech Sheet. United States Department of Agriculture. Archived from the original on 2015-02-12. Retrieved 2010-12-15.
• "Irvingia gabonensis (Aubry-Lecomte ex O'Rorke) Baill". Protabase record display. Prota. Archived from the original on 2015-02-12. Retrieved 2010-12-15.

• Irvingia gabonensis in West African plants – A Photo Guide.