Maesopsis eminii (Umbrella Tree)

Scientific name

Maesopsis eminiiEngler

Synonyms

Karlea berchemioides Pierre; M. berchemioides (Pierre) A. Chev.

Common names

Umbrella tree, musizi

Family

Rhamnaceae

Origin

Native to tropical West and Central Africa and parts of eastern Africa (Uganda).

Naturalised distribution (global)

Locations within which Maesopsis eminii is naturalised include Puerto Rico, India and parts of eastern Africa to which it is not native.

Introduced, naturalised or invasive in East Africa

Maesopsis eminii is invasive in parts Tanzania (Haysom and Murphy 2003) and is known to be introduced in Kenya (Maundu and Tegnas 2005). The species is indigenous to Uganda where it grow in moist evergreen forests and moist semi-deciduous forests as well as in grasslands and seasonal wetlands at altitudes of 700 to 1500m. In Uganda it has not exhibited any weediness, perhaps due to presence of some natural enemies (D.L.N. Hafashimana pers. comm.). It was introduced first in German colonial times in the Usambara mountains in eastern Tanzania, then in the 1930s and 1960s, it has rapidly invaded submontane rainforest, to become the dominant species there.

Habitat

Moist forests, particularly forest edges. It occurs from lowland tropical rain forest to savanna, extending into submontane forest up to 1500 m altitude.

Description

Maesopsis eminii is an unarmed, evergreen to deciduous tree which can reach up to 15-25(-45) m tall with an open and spreading crown. Its bole is exceptionally straight, cylindrical, measures up to 15 m tall and 50(-180) cm in diameter, while the buttresses are small or absent. The bark is pale grey to grey brown or almost white, smooth or with deep, vertical and often twisted furrows. The branchlets are with patent short hairs.

The leaves are mostly almost paired (subopposite), simple and glandular-serrulate (having minutely serrated margins). The stipules (leafy structure at the base of leaves) measure 2-6 mm long, puberulent (covered in short, fine hairs) and caduceus (drop off quickly). The petiole is 6-12 mm long and hairy to nearly hairless. The blade is ovate (egg-shaped in outline with broad end at base)-elliptical to oblong-ovate, measuring 7-14 cm x 2.5-6 cm, lustrous above and paler beneath. It is smooth except when young, with rounded to subcordate (somewhat heart-shaped) base, and acuminate (gradually tapering) at apex, while the margins are 0.3-5 mm long and with rounded teeth.

The inflorescence is a many flowered axillary cyme and measures about 1-5 cm long. The peduncle is 4-25 mm long. The flowers are bisexual, 5-merous and yellowish-green. The pedicel is 1-3(-6) mm long. The sepals are 2-6 mm long and deltoid, while the petals are very strongly concave-convex, hiding the anthers and not clawed. The anthers are subsessile with short style and dilated. The stigma is stellately 10-lobed. The style and stigma are persistent in fruit.

The fruit is an obovate (egg-shaped but with the narrower end at the base) drupe, measuring 20-35 mm x 10-18 mm, turns from green to yellow to purple-black when mature. The mesocarp is floury and cream-coloured while endocarp is creamy-brown.

Reproduction and dispersal

Small yellow/green flowers are hermaphroditic and probably pollinated by various insects. Flowers and fruits are produced after four to ten years. Flowering can occur in wet or dry seasons, and fruit take three or four months to develop after pollination. There are usually 1 or 2 fruits per inflorescence. Drupes are 22-30 mm long and 10-16 mm thick. Seeds are produced every year or every six months. Seeds germinate when the soil is humid.

Birds such as hornbills and sometimes monkeys (particularly chimpanzees) disperse drupe-containing seeds as they carry the fruit to eat the sweet thin fleshy pulp around the woody seed.

It is distributed by people for use as a fast growing timber tree.

Economic and other uses

Maesopsis eminii has been introduced for timber production and as a shade tree. Most people have little use for the wood as it is readily attacked by fungi and insects. However, in areas where timber is scarce, local people may consider M. eminii an important timber tree (Cronk and Fuller 1995). In Uganda, in addition to the naturally growing trees in the forests and woodlands, M. eminii is widely grown in plantations and as individual trees and is very popular for general purpose timber. The timber is strong and durable when it is harvested when the wood is mature. It is gaining more popularity as it has a fast maturation period comparable with introduced coniferous trees (pine and cypress) and it produces comparatively more wood per unit area.

Environmental and other impacts

Maesopsis eminii can colonise forest gaps and become dominant in logged and disturbed forests. It can alter soil properties as follows:  upper organic soil horizons disappear; dense superficial root mat disappears; litter becomes thinner; pH increases; soil fauna changes in species composition to become more uniform; and a possible increase in the rate of soil erosion. These changes in the soil affect many native species. The plant produces many seeds which makes control difficult. Seedlings are shade-tolerant so can grow in undisturbed forest.

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 when there is little fruiting, but the bark must be removed from the stumps to kill the tree and prevent coppicing. Seedlings and saplings can be dug out. Mechanically removing trees should be accompanied by planting native pioneer species. Logging and disturbance of forest (other than removing Maesopsis eminii) should be prevented, as the plant is likely to invade disturbed areas.

Herbicides can be used to kill trees, although the editors could not find any documentation of control methods. It is likely that cut stump or basal bark methods (painting herbicide onto the bark) using a suitable herbicide can be used on larger plants and foliar sprays can be applied to small plants. When using any herbicide always read the label first and follow all instructions and safety requirements. If in doubt consult an expert.

The editors could find no information on any biological control agents for this species.

Legislation

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

References

Binggeli, P. (1998). An Overview of Invasive Woody Plants in the Tropics. School of Agricultural and Forest Science, University of Wales, Bangor. http://members.lycos.co.uk/WoodyPlantEcology. Accessed February 2011.

Cronk,  Q.C.B. and Fuller, J.L. (1995). Plant Invaders. Chapman and Hall, London.

Haysom, K.A. and Murphy, S.T. (2003).The status of invasiveness of forest tree species outside their natural habitat: a global review and discussion paper. Forest Health and Biosecurity Working Paper FBS/3E. Forestry Department. FAO, Rome (unpublished).  www.fao.org/docrep/006/j1583e/j1583e00.htm.

Pacific Island Ecosystems at Risk (PIER). Maesopsis eminii Engl., Rhamnaceae: plant threats to Pacific ecosystems. www.hear.org/pier/species/maesopsis_eminii.htm. Accessed February 2011.

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