Une forte saisonnalité du climat et de la phénologie reproductive dans la forêt du Mayombe: l’apport des données historiques de la Réserve de Luki en République démocratique du Congo

In Africa, the reproductive phenology of tropical trees is mostly annual and regular. This study documents the intra- and inter-annual reproductive phenology of trees in the Mayombe forest, from historical data on the Luki Reserve in the Democratic Republic of the Congo. Reproductive diameter, which is a key parameter for forest management but is largely unknown for many timber species, was also documented for the most abundant species in the dataset. Phenological monitoring of 3,642 trees belonging to 158 species and 39 families was conducted in the Luki Reserve every 10 days from 1948 to 1957. Circular statistics were used to test the synchronicity of phenological events among trees, both at the community level, i.e. for the forest as a whole, and individually for 87 species, which included 35 well-represented species (n ≥ 20 trees), 16 commercial species and 36 other species. Logistic regressions were used to determine the diameter (minimum and regular) of these species on fruiting. Reproductive phenology for the majority of the trees and the species is largely seasonal, annual and regular (81.6%, 71 species). The peaks for flowering are more abrupt than the fruiting peaks and more spread out over time, although the timing of flowering and fruiting is significantly aggregated. Most of the trees and species bloom from December to February, during the short dry season, but flowers and fruits can be observed throughout the year within the community. Only 13 species showed a significant relationship between diameter and reproduction, including seven canopy species, five understory species and one light-demanding species. For these 13 species, the average minimum reproduction diameter was 17.3 cm.