Can the Mangombe forest plantation contribute to restore and conserve biodiversity?

International audienceThis research, conducted in the tropical rainforest, is focused on restoration of tree diversity through natural regeneration mechanism in the 49 year-old Mangombe forest plantation. 12 plots were surveyed, 6 with large transects and the 6 others under regrowth. In each plot, two subplots with 400 m² each were demarcated for the inventory of all stems with diameter greater than 2.5 cm. A total of 2239 stems comprising 107 species distributed in 93 genera and 42 families were identified over 9600 m². There was a slight difference between species richness of plots with large transect (79 species, 72 genera and 35 families) and regrowth plots (85 species, 76 genera and 38 families) while the basal area in the plots with large transects (10.76 m²/ha) was significantly greater than that of regrowth (8.65 m²/ha). Species with high important value index have an affinity with forest undergrowth such as: Tabernaemontana pachysiphon, T. crassa, Mallotus oppositifolius and Heinsia crinita. The undergrowth is diversified with different life feature and a high number of small size trees indicating a vigorous regeneration. This can be favoured by: microclimate undergrowth, canopy gaps, abundance of litter fall that brings humus to the soil, type and age of plots, planted species and the complexity of spatial and vertical structure of the stand