Fruit Productivity of “African locust bean” along a climatic gradient in Burkina Faso

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Résumé

Parkia biglobosa (Jacq.) R. Br. ex G. Don is highly valued species in many domains as food. However, the overexploitation of its fruits is one of the main causes of the species' vulnerability. Accurate assessment of annual fruit production could contribute in better conservation of the species. This study aims to assess fruit productivity of Parkia biglobosa and the relative proportion of the Non-Timber Forest Products (NTFPs) derived from the fruit. Fruit productivity was determined using a sample of 144 trees distributed across 6 diameter classes at 8 sites identified in two climatic zones. Seeds and husks were dried separately and then weighed. The weight of the pulp was obtained by subtracting the weight of the husk and seeds from the total weight of the fruit. The result revealed that fruit productivity is higher in the sudanian climatic zone than in the sudan-sahelian zone in Burkina Faso. The relative proportion of the NTFPs derived from the fruit varies according to climatic zones. Stem diameter at breast height (DBH) was the dendrometric parameter that better predicted fruit productivity of P. biglobosa. The best allometric equations of fruit production for both zones are: Total fruit biomass (Kg) = 0.8 DBH - 14.5 and Total fruit biomass (kg) = 5 ln DBH - 13.6. The observed variations in P. biglobosa NTFP productivity may reflect the species’ response to climate change. However, since the species is also exposed to considerable anthropogenic pressure, validating this hypothesis requires an ethnobotanical study to ascertain that anthropogenic influences are comparable across the different climatic zones.

Mots-clés

Parkia biglobosa, biomass, Non-Timber Forest Products (NTFPs), allometric model