Moderate C storage, weak conservation ability and the need to renew old cocoa plantations from the Talba forest pioneer front in Centre Cameroon

Ndje Mbile Jean-Guy, Saj Stéphane, Enock Seguy, Mala William, Harmand Jean-Michel. 2022. Moderate C storage, weak conservation ability and the need to renew old cocoa plantations from the Talba forest pioneer front in Centre Cameroon. In : En transition vers un monde viable. Québec : Université de Laval-IUAF-ICRAF, Résumé, 1 p. Congrès mondial d'agroforesterie. 5, Québec, Canada, 17 Juillet 2022/20 Juillet 2022.

Url - éditeur : https://conferium.com/Clients/226_web/index.lasso?lang=fr

Résumé : In Cameroon, cocoa plantations of the Talba pionner front are set up after partial, yet strong, forest clearing and planted with " hybrid " cocoa trees. Previous studies showed complex relationships between preserved forest trees and cocoa yields, which need to be investigated further. In this peculiar cocoa production zone, we studied a chronosequence of 32 cocoa plantations (8 to 73 years old). We measured cocoa and associated trees diameter, height, shade tree cover and cocoa yield. We also estimated basal area and tree biomass. Talba plantations showed a low density of associated trees (32 trees.ha-1) in comparison to other production zones in the country (80 -150 trees.ha-1) and consequently a 35-55% lower carbon storage in aerial biomass (48 Mg.ha-1). The average shade cover was also low (38%) and positively linked to the basal area of associated trees. Associated trees were preserved for timber (Terminalia superba) and/or for their high economic value (Ricinodendron heudelotii). Introduced trees were mainly for self-consumption (Dacryodes edulis). Specific diversity tended to reduce until [40-60] years old. Hence, in the mid-term, these plantations would lose their already low tree species conservation value if farmers were not rapidly encouraged to keep or renew forest-preserved trees. The age of the plot and, to a much lesser extent, the shade tree cover affected negatively cocoa yield. Other canopy attributes did not affect cocoa yield. Cocoa tree density decreased significantly with plot age. The absence of a relationship between the individual cocoa tree and the plot age suggests that the yield decrease with time was mainly due to a lack of renewal of old cocoa trees through coppicing and/or new seedlings planting. The low number of multi-stem cocoa trees in our study area confirms that rejuvenation of old plantations is a challenge for the farmers towards sustainable cocoa production.

Auteurs et affiliations

• Ndje Mbile Jean-Guy, IRAD (CMR)
• Saj Stéphane, CIRAD-PERSYST-UMR ABSys (GUF) ORCID: 0000-0001-5856-5459
• Enock Seguy, ICRAF (CMR)
• Mala William
• Harmand Jean-Michel, CIRAD-PERSYST-UMR Eco&Sols (CMR) ORCID: 0000-0002-8065-106X

Source : Cirad-Agritrop (https://agritrop.cirad.fr/601943/)

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