Sapele

The sapele is a long-lived and slow-growing tree that plays an important ecological role in the forests of west and central Africa (1) (3) (6). Sapele trees provide habitat for a number of rare monkeys in the Congo forests, such as Thollon's red colobus (Procolobus badius tholloni) and mandrills (Mandrillus sphinx) (6), and during the summer, the trees are also the unique host to a species of caterpillar Imbrasia (Nudaurelia) oyemensis (7) (8). These caterpillars provide an important source of protein for forest-dwelling communities, and also an important source of income; collecting caterpillars can provide a higher annual income per hectare than growing crops (7). How the large sapele tree reproduces is not entirely clear. It was considered to be hermaphroditic, with each flower containing both male and female organs, but more recent studies suggest that each sapele tree bears separate male and female flowers (3). Sapele trees begin to flower when they have a diameter of 20 centimetres, but only begin producing seeds when reaching a diameter of about 50 centimetres. Flowering occurs from November to February (5), and like other trees of the mahogany family, (Meliaceae), the sapele is pollinated by insects, primarily bees and moths (3). Each year, about one-third of mature sapele trees produce fruits, but flowering and fruiting are irregular among individuals and years, and seed production is erratic (3). As well as housing protein-rich caterpillars, the sapele is also critical to local communities for their medicinal and structural properties. The bark of the sapele is believed to have anti-inflammatory properties and is used for the treatment of headaches, eye infections and swollen feet, and the trunk is used for dug-out canoes and the central roof support in homes (7).

There are protected populations of the sapele tree, and felling limits in various countries (1). In addition, successful plantations have been established in the Côte d'Ivoire (10), which will lessen the pressure on wild populations and the animal and human communities that rely on them.

This tall, straight African tree holds incredible value; ecologically, commercially, and even medicinally. The sapele is a member of the mahogany family, a group of trees which play an important structural role within tropical forests and have a high commercial value for their timber (3). The wide trunk bears no branches or leaves until around 30 metres (2), and has fairly dark, reddish or purplish brown heartwood, while the outer-wood is white to light rosy-red (4), covered with brownish-grey bark that is often peeling off in patches (5). The symmetrical crown of the sapele consists of pinnate, alternate leaves (4) (5), and the numerous, small flowers consist of five petals and bloom in loose, open clusters (4) (5). The fruits are elongated, woody capsules, and contain many brown, winged seeds. The sapele emits a distinct cedary odour (4).

Sapele trees grow scattered in tropical evergreen and semi-deciduous forests (1) (3). They can also be found in drier habitats, including abandoned fields (1).

The sapele is distributed in Africa, in Sierra Leone, east to Uganda and south to Angola (1).

Classified as Vulnerable (VU) on the IUCN Red List 2007 (1)

Sapele trees are a major source of African mahogany (1), with a high commercial value (3), and are therefore exploited heavily throughout their range (1). For example, sapele composes over 70 percent of the timber harvested in the northern Congo (9), and exploitation has led to supplies from West Africa being exhausted (8). Harvesting of the sapele destroys important habitat for many species, and a source of protein and income for local communities. The future of this precious tree is bleak if harvesting at this level continues without adequate management (9).