Effects of leaf harvesting intensity on fruiting processes in three fodder tree species in the West African Savannah

Abstract

Leaf harvesting from fodder trees is one of the major forms of forest disturbance in West Africa, and its frequency is increasing in the wake of climate change. The impacts of leaf harvesting on fruits appearance of Afzelia africana Smith ex Pers., Khaya senegalensis (Desr.) A. Juss., and Pterocarpus erinaceus Poir, particularly in natural savannas, remain largely unexplored. This study explored three fodder species, (i) the minimum fruiting diameter, (ii) the time for the appearance of the first fruits after leaf harvest and (iii) the fruiting diameter most vulnerable to leaf harvest in two ecological zones in Benin. In total, 1040 individuals were examined, including 257 A. africana, 210 K. senegalensis, and 573 P. erinaceus from nine forest reserves in the Sudano-Guinean and Sudanian zones over three years (2021–2023). In the two ecological zones, the average diameters of the fruiting trees were 10 cm for K. senegalensis, 20 cm for P. erinaceus, and 15–20 cm for A. africana. The DBH, harvest intensity, and post-harvest duration were associated significantly with post-harvest fruit appearance. Low and medium leaf harvesting intensities did not prevent fruiting in the three species. Conversely, full leaf harvesting prevented fruiting in A. africana and K. senegalensis for at least two years, unlike in P. erinaceus, which fruited a year later. Stem shoot emergence in large-diameter trees in all three species, which facilitates fruiting, was impaired after leaf harvesting. Considering the results, leaf harvest intensities greater than 75 % should be discouraged to allow the three species to fruit each season to ensure seed availability for natural regeneration.