Past studies showed a gradual expansion of tree cover over savannah in the forest–savannah boundary zone of Cameroon (Gillet et al. 2001). While the encroachment of savannah by forest is more and more impeded by human activities, farmers have proven that afforestation at the border of the forest is achievable using cocoa and specific techniques to build up an associated tree canopy (Jagoret et al. 2012). Furthermore, mature cocoa agroforestry systems created on savannah (S-cAFS) and in forest (F-cAFS) seem to exhibit comparable multi-strata structure linked to a multi-purpose objective of farmers in terms of livelihoods and long-term sustainable management of cocoa. By combining measurements of cocoa production, litterfall and cycling, soil quality, carbon storage and tree species diversity along an age gradient (1 to 70 years), we showed that those variables in S- and F-cAFS generally tended to comparable levels after several decades. Results also emphasized the ability of S-cAFS to increase most of the ecosystem services (ES) although the time needed to reach levels found in F-cAFS varied strongly amongst variables (Nijmeijer et al. 2019a,b). We also compared the impact of five shade tree species (Canarium schweinfurthii, Dacryodes edulis, Milicia excelsa, Ceiba pentandra, Albizia adianthifolia) and unshaded conditions on soil functions and cocoa yield in relation to plant functional traits and leaf litterfall within 8 cocoa farms 20 to 60 years old (Sauvadet et al. 2020). While no difference in cocoa yields could be detected between the different tree species and unshaded conditions because of high variability of data, the effects on soil functions varied largely among species. Shade tree species with the most dissimilar litter traits to cocoa (cocoa showing the lowest leaf litter quality) showed the largest improvement of soil functions. Low litter recalcitrance was strongly associated with increases in soil fertility indicators such as N and P availability, whi