Cocoa stand rehabilitation practices affect cocoa production in the long run in agroforestry systems in Cameroon

In Cameroon, farming practices that drive productivity vary according to the production area and its local history. Previous studies have demonstrated that tree density and diversity play a crucial role in the long-term stability of cocoa agroforestry systems (cAFS). Concomitant regeneration practices for cocoa stands under shade conditions have led to acceptable cocoa production beyond 100 years of age; however, these rehabilitation practices require further investigation. Our study aims to identify cocoa farm rehabilitation practices that contribute to sustainable production in the long run. We studied 46 cocoa plantations in two different areas: a forest pioneer front (Talba) and an old cocoa production area (Bakoa). We measured the diameter, basal area, and height of cocoa and associated trees, as well as the shade tree cover, and estimated the carbon (C) storage of these trees. We also identified architectural types corresponding to different stages of cacao tree development and measured cocoa yield. Our results showed no significant effect of age on all characteristics of associated trees (cover, density, basal area, and carbon storage). However, regarding basal area, the cAFS of Bakoa can be classified as complex (19.1 m2 ha-1) compared to the simplified systems in Talba (8.8 m2 ha- 1). The density of total cocoa trees decreased significantly with the age of the plantations in Talba (from 1287 ind ha-1 in young plantations to 848 ind ha-1 in ancient plantations). Still, no significant change was found in Bakoa. Furthermore, total cocoa yield decreased significantly with cAFS aging only in Talba (Figure 1). We observed a higher contribution of regenerated multi-stem cocoa trees to the total yield in Bakoa (54%) than in Talba (23%). In Bakoa, the renewal of old cocoa plantations was achieved through coppicing and seedling planting, whereas in Talba, it was practiced much less frequently, primarily through seedling planting. The lack of rehabilitation of mature and old cocoa plantations in Talba can be explained by the fact that farmers still had the opportunity to establish new cocoa plantations in secondary forests, which was not the case in Bakoa. The study revealed that in Central Cameroon, the rehabilitation of old cocoa plantations is dependent on the production area and appears to be linked to the local availability of land for crop expansion. In an area with no available forest reserves, such as Bakoa, the renewal process of cocoa plantations led to sustainable cocoa production. Promoting these practices in areas with available forest reserves, such as Talba, to create new plantations, in addition to increasing the output of existing cocoa plantations, could help limit deforestation.