Elaeis guineensis (African Oil Palm)

Scientific name

Elaeis guineensisJacq.

Synonyms

E. melanococca  J. Gaertn.

Common names

African oil palm, mchikichi, mjenga (Kiswahili), mubira, munazi (Luganda)

Family

Arecaceae

Origin

West Africa coast from Liberia to Angola and the tropical rainforest belt from west to Central Africa, reaching its easternmost range in Western Uganda (Semliki National Park in the Albertine Rift).

Naturalised distribution (global)

Locations within which Elaeis guineensis is naturalised include some dry areas of Pacific islands and in remnants of Atlantic Forest in Bahia state, Northeast Brazil.

Introduced, naturalised or invasive in East Africa

Elaeis guineensis is invasive in parts of Tanzania (Tropical Biology Association 2010, GISD 2006). African oil palm has been introduced to Kenya and eastern Uganda but the editors are not aware of records of it being naturalised or invasive in these countries.

Habitat

Natural forests, ruderal/disturbed

Description

Elaeis guineensis is a tall palm typically reaching, 8-20 m tall. The trunk is stout, erect, solitary, covered by the persistent leaf-bases above, bare below, dark grey-brown and ringed.

Leaves are large, compound (pinnate), the lower segments as spines on the leaf stalk (petiole) margin; segments many, irregularly divergent, somewhat clustered (fascicled) in 4's or 5's.

Male and female flowers in separate clusters, but on same tree (monoecious). Inflorescence large, head-like, with spiny tipped branches borne close to the trunk, among the leaves, The fruits are green turning orange later. The fruits are born in large clusters of 200-300, close to trunk on short heavy stalks (pedicels). The fruits are plum-like, ovoid-oblong to 3.5 cm long and about 2 cm wide, black when ripe, red at base, with thick ivory-white flesh and small cavity in centre. The nuts are encased in a fibrous covering which contains the oil.

Reproduction and dispersal

Fruits are produced after 3-4 years and ripen 5 or 6 months after pollination. The seeds are dispersed by animals.

Economic and other uses

Elaeis guineensis is widely cultivated for oil from its fruits from which palm oil and palm kernel oil are extracted (Barker and Worgan 1981). The oils are used in manufacturing and foodstuff production.

Environmental and other impacts

Elaeis guineensis can invade forest edges and gaps inhibiting the regeneration of native species in moist forests. It thrives in riverine forests or in freshwater swamps. It cannot thrive in primeval forests and does not regenerate in high secondary forests. It is now showing potential of spreading from cultivation to become invasive in many dry areas of Pacific islands, It has become very invasive in remnants of Atlantic Forest in Bahia state, Northeast Brazil (GISD 2006). E. guineensis has been included in the Global Invasive Species Database (GISD 2006).

Management

The precise management measures adopted for any plant invasion will depend upon factors such as the terrain, the cost and availability of labour, the severity of the infestation and the presence of other invasive species. Some components of an integrated management approach are introduced below.

The best form of invasive species management is prevention. If prevention is no longer possible, it is best to treat the weed infestations when they are small to prevent them from establishing (early detection and rapid response). Controlling the weed before it seeds will reduce future problems. Control is generally best applied to the least infested areas before dense infestations are tackled. Consistent follow-up work is required for sustainable management.

Trees can be cut down, but chemical control must be used on cut stumps to prevent resprouting. When using any herbicide always read the label first and follow all instructions and safety requirements. If in doubt consult an expert.

The editors are not aware of a biological control programme for this species. Any biological control programme for a species such as this which is grown on a large scale is likely to engender conflicts of interest.

Legislation

Not listed as a noxious weed by the state or governments in Kenya, Tanzania and Uganda.

References

Barker, T.W. and Worgan, J. T. (1981). The utilization of palm oil processing effluents as substrates for microbial protein production by the fungus Aspergillus oryzae. Eur. J. Appl. Microbio. & Biotechn. 11(4):234-240.

GISD (2006). Global Invasive Species Database. Elaeis guineensis (palm). www.issg.org/database. Invasive Species Specialist Group.

Tropical Biology Association (2010). Usambara Invasive Plants - Amani Nature Reserve - www.tropical-biology.org/research/dip/species.htm.

Editors

Agnes Lusweti, National Museums of Kenya; Emily Wabuyele, National Museums of Kenya, Paul Ssegawa, Makerere University; John Mauremootoo, BioNET-INTERNATIONAL Secretariat - UK.

Acknowledgments

This fact sheet is adapted from The Environmental Weeds of Australia by Sheldon Navie and Steve Adkins, Centre for Biological Information Technology, University of Queensland. We recognise the support from the National Museums of Kenya, Tropical Pesticides Research Institute (TPRI) - Tanzania and Makerere University, Uganda. This activity was undertaken as part of the BioNET-EAFRINET UVIMA Project (Taxonomy for Development in East Africa).

Contact

BioNET-EAFRINET Regional Coordinator: eafrinet@africaonline.co.ke