Dynamics of Natural Stands and Response of Seedlings to the Action of Controlled Fire of Three Overexploited Species in the Sudanian Zone (Cote d-Ivoire)

Both natural and anthropic disturbances affect integrity of classified forests in northern Côte d'Ivoire, to point that certain valuable species and their habitats are threatened with extinction. Our work aims to study the structural characteristics and the impact of bush fire regimes on young plants of Isoberlinia doka Khaya senegalensis and Pterocarpus erinaceus. from classified forests of Palé and Pouniakélé in north-western Côte d'Ivoire. Data was collected by the surface survey method in 10 plots of one hectare per forest. Dendrometric measurements were carried out in order to determine structural profiles of species studied. An experimental plot made it possible to assess effect of bushfire regimes on the juvenile stage of species. Dendrometric parameters show significant differences with density and mean diameter of the individuals. The densities of individuals (dbh ≥ 5 cm) of these valuable species are relatively low (0.2-117 individuals / ha), regardless of the forest. In Palé classified forest, three plants species are destructive, synonymous with the instability of their populations. On the other hand, in Pouniakélé forest, Isoberlinia doka have a more stable population than the other two. Pterocarpus erinaceus and especially Khaya senegalensis are the most vulnerable species in the two plant formations. Late fire has been shown to be the most aggressive on young plants of the species, although the depressive effect can be immediate or delayed depending on whether the seedlings are less than a year old or more than a year old.