African Walnut
Coula edulis

Family: Olacaceae

What it is like

Coula edulis or African Walnut is an evergreen tree native to western Africa with a dense crown and grows up to 38 m in height. The leaves are simple and arranged alternately. The flowers are greenish yellow with four or five petals. The nut is an ellipsoidal drupe, smooth and red or green in colour. It is also known as Gabon nut. Plant parts have various uses. The nut is eaten raw or cooked. It can also be fermented and used as a condiment. The wood is very hard, heavy, and durable. It is resistant to attacks of fungi, termites, and marine borers. It is used in turnery, heavy carpentry, piles for bridges, etc.

Coula edulis is an evergreen Tree growing to 20 m (65ft) by 20 m (65ft) at a medium rate. See above for USDA hardiness. It is hardy to UK zone 10. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very acid and very alkaline soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

Height (m): 20

Where it is found

It has its main distribution in the rain forest. Tolerates moderate shade and is normally a constituent of the upper reaches of the lower storey but is also found in the upper canopy. Semi-gregarious, it does not appear to be selective about sites.

Western Tropical Africa - Democratic Republic of Congo, Nigeria, Sierra Leone.

Conservation Status: This taxon has not yet been assessed

Countries/locations it is found in

Africa, Benin, Cameroon, Central Africa, Central African Republic, CAR, Congo DR, Congo R, Cote d'Ivoire, East Africa, Gabon, Ghana, Ivory Coast, Liberia, Nigeria, Sierra Leone, Togo, West Africa.

How it is used

Food

Rating: 3

Seed - raw or cooked. A good dessert nut with a pleasant taste. The oily kernel has a taste comparable to that of a chestnut or hazelnut. It can be eaten raw, grilled or boiled. The seed contains 50% oil, of which 87% is oleic acid. The seed is also fermented and used as a condiment. The spherical fruit is about 3cm long.

Oil: Oil

Seed: includes nuts, cereals, peas and beans.

Condiment: the various plants that are used as flavourings, either as herbs, spices or condiments.

Medicine

Rating: 0

Other

Rating: 4

Other Uses: The heartwood is dark red or violet brownish-red with dark brown veins; it is clearly demarcated from the 3 - 4cm wide band of pinkish-brown sapwood. The texture is fine; the grain straight or interlocked, sometimes wavy. The wood is very hard, very heavy, elastic, and very durable, resisting water well and resistant to fungal and insect attack, particularly termites and marine borers. It seasons slowly, with a high risk of distortion and checking; once dry it is moderately stable in service. The wood has a fairly high blunting effect upon tools, stellite-tipped and tungsten carbide are recommended; it polishes well; is easy to work, but has the disadvantage of being liable to shake and crack; it takes nails and screws well so long as it is pre-bored; gluing is correct for interior use only. In great demand, the wood is used in turnery and as a substitute for mahogany, as well as for heavy carpentry, industrial flooring, piles for bridges and railway ties. The wood produces a suitable charcoal.

Charcoal: Used for fuel, drawing, deodorant, filter, fertilizer etc.

Furniture: A few miscellaneous uses that do not fit easily into other headings.

Oil: Vegetable oils have many uses, as lubricants, lighting, soap and paint making, waterproofing etc. This does not include the edible oils unless they are also mentioned as having other uses.

Wood: A list of the trees and shrubs that are noted for having useful wood.

Management: Standard: Plants grow to their standard height. Harvest fruit, seeds, or other products. Non-Destructive management systems.

Regional Crop: These crops have been domesticated and cultivated regionally but have not been adopted elsewhere and are typically not traded globally, Examples in this broad category include perennial cottons and many nuts and staple fruits.

Management: Standard: Plants grow to their standard height. Harvest fruit, seeds, or other products. Non-Destructive management systems.

Regional Crop: These crops have been domesticated and cultivated regionally but have not been adopted elsewhere and are typically not traded globally, Examples in this broad category include perennial cottons and many nuts and staple fruits.

Carbon Farming: Plants that can be a critical part of the solution to climate problems. The Carbon Farming Solution - Eric Toensmeier.

Food Forest: Plants for Edible Forest Gardens and Food Forests.

How it is grown

A plant of the hot, humid, lowland tropics. It grows best in areas where annual daytime temperatures are within the range 25 - 35°c, but can tolerate 20 - 40°c. It prefers a mean annual rainfall in the range 1,000 - 2,000mm, but tolerates 800 - 2,500mm. Succeeds in full sun and in partial shade. Shading is beneficial when plants are young. The tree has no special soil requirements. Prefers a well-drained soil. Prefers a pH in the range 5 - 6.5, tolerating 4.5 - 7. Fruit is normally borne plentifully in the wild.

Propagating it: Seed - Because of the hard integument, germination is rather poor and may take up to a year.

Best place to grow:

Habit: Tree

Hardiness: 10-12

Growth: Medium

Soil: Light (sandy), medium, heavy (clay)

Shade: Semi-shade, no shade

Moisture: Moist

Things to keep in mind

Its other names

Local names

Coula edulis or African Walnut. Also known as: Attia, Bodwe, Ekom, Emumu, Engom, Ewome, Ewoumeu, Fiya-towo, Gaboon-nut, Ivianlegbe, Kommol, Kumen, Kumini, Kumumu, Kumunu, Mengom, Ndokei, Ngoma, Noyer du pays, Slah, Sweh, Tokei, Udi, Woula,

Synonyms

Coula cabrae Wildem et Th. Dur.