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

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.