Okoubaka tree
Okoubaka aubrevillei

Family: Santalaceae

What it is like

Okoubaka aubrevillei is a deciduous tree growing about 30 m in height and native to tropical Africa. It has a straight and cylindrical bole that can be up to 80cm in diameter. The crown is comprised of branches that hang low down. The bark is used medicinally for skin disorders and poisoning. It is found to have antimicrobial and immuno-stimulating properties. The wood of this species is sometimes used for constructions or as firewood.

Okoubaka aubrevillei is a deciduous Tree growing to 23 m (75ft) 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, prefers well-drained soil and can grow in nutritionally poor soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It cannot grow in the shade. It prefers dry or moist soil and can tolerate drought.

Height (m): 23

Where it is found

Forests on rocky hills, usually solitary but occasionally in pure stands in Ghana and Cote D'Ivoire.

West tropical Africa - Sierra Leone to Cameroon and DR Congo.

Conservation Status: Status: Endangered C2a(i)

Countries/locations it is found in

Cameroon; Central African Republic; Congo, The Democratic Republic of the; Côte d'Ivoire; Gabon; Ghana; Guinea; Liberia; Nigeria; Sierra Leone

How it is used

Food

Rating: 0

Medicine

Rating: 4

The bark is widely used as a medicine in west Africa and is also exported to Europe and other countries. It is particularly employed in the treatment of skin disorders and poisoning. Six different catechins have been isolated from the bark, including (+)-catechin and (+)-gallocatechin, as well as_-sitosterol and stigmasterol. The bark has antimicrobial and immunostimulating properties that are attributed to phenolic compounds. A macerate of the bark is used in the treatment of tachycardia. The bark is used in phytotherapeutic medicine in the Western world. Its main applications are for stomach upsets caused by poisoning and to boost the system in cases of tiredness, depression and allergies. Skin problems, including those caused by syphilis and leprosy, are treated by washing with, or bathing in a macerate or infusion of the bark in water. External application of bark preparations is also practised to counteract poisoning. A bark macerate is taken as a vapour bath or as nose drops to cure oedema. In a compress it is used to disperse haematomas. A wooden tool is traditionally used for the removal of the bark, and under no circumstances is a metal implement used.

Antibacterial: Kills bacteria.

Antidepressant: Used to alleviate mood disorders, such as major depression and dysthymia and anxiety disorders such as social anxiety disorder.

Antidote: Counters poisoning.

Antifungal: An agent that inhibits or destroys fungi. Used in the treatment of various fungal problems such as candida.

Leprosy: Used to treat leprosy - a chronic bacterial infection of the skin and superficial nerves (in the skin) caused by Mycobacterium leprae.

Skin: Plants used in miscellaneous treatments for the skin.

Tonic: Improves general health. Slower acting than a stimulant, it brings steady improvement.

Other

Rating: 2

Other Uses The wood is sometimes used for construction or as firewood.

Fuel: Usually wood, plant materials that have been mentioned as being a good fuel.

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

How it is grown

Natural regeneration is poor, because the fruits and seeds are eaten by porcupines. In southern Nigeria, Okoubaka aubrevillei is an important tree in religious ceremonies. It is considered to be a mystery plant in Cote D'Ivoire, and nobody would fell it. It belongs to a family of plants that includes many parasitic and hemiparasitic species and is said to kill trees around its growth place, though it has not been proven to be parasitic. Okoubaka aubrevillei is a hemi-parasitic plant. Within 6 months after germination, when nutrient reserves in the seed become depleted, the roots attach themselves to those of nearby plants by means of haustoria. However, one year after germination no differences were found in growth and foliar nutrient concentrations between plants growing with and those without hosts. The hosts, however, showed increased mortality or reduced growth. Hence, the apparent benefit which this species gains from the parasitic association is killing potential competitors for water, light and nutrients. The only tree species surviving close to it are Myrianthus arboreus and Musanga cecropioides.

Propagating it: Seed - germination rates of 60 - 100% have been recorded. Attempts have been made to cultivate this species. After germination, the seedlings were transplanted in rows 4 metres apart, at a distance of 2 metres within the rows. Between the rows, Millettia laurentii was planted to act as a host. After about 10 years, 54% of the plants had survived and had reached an average height of 4.2 metres, with a maximum height of 8.6 metres. The host plant, Millettia laurentii, grew well for the first 6 years, but then started dying.

Best place to grow:

Habit: Tree

Hardiness: 10-12

Growth: Medium

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

Shade: No shade

Moisture: Dry, moist

Things to keep in mind

The bark is used as a fish poison.

Its other names

Local names

Okoubaka tree, okoubaka aubrevillei

Synonyms

Octoknema okoubaka Aubr?v. & Pellegr.