Silviculture of productive secondary forests in Gabon (Central Africa)

The different types of secondary forests are not equally distributed across Africa. In West Africa, most secondary forests are young, corresponding to forest fallows or logged-over residual forests. Secondary successions of these types are generally not favourable either to regeneration of high commercial value species or to conservation of biodiversity. To offset economic and ecological threats the use of Reduced Impact Logging is crucial. In Central Africa, there is less human pressure for cultivation and logging is generally very selective (less than one tree per ha). Secondary succession as described above is fairly limited. Most secondary forests are old forests and generally they result from the very slow colonisation of savannas, to which the present climate is favourable. They cover a large area, and are thought difficult to evaluate. These forests are sometimes rich in 'long-life' pioneer species with high commercial value; #Aucoumea klaineana (Burseraceae)# in Gabon is a well-known example. When they reach maturity these species are unable to find favourable conditions (mainly light) without human intervention. Forest management in stages of succession must have clear objectives and should encourage durability of long-life pioneer species if necessary. (Résumé d'auteur