Productivity of Theobroma cacao agroforestry systems with timber or legume service shade trees

Abstract

Timber production and cocoa yields were studied (initial 10-11 years) in two experimental plantations: a Cocoa-Legume system (CL, Erythrina poeppigiana, Gliricidia sepium or Inga edulis), and a Cocoa-Timber system (CT, Cordia alliodora, Tab- ebuia rosea or Terminalia ivorensis, plus I. edulis for inter-site comparisons). These trials had two major goals: (1) to evaluate the use of mono-specific timber shade canopies as an alternative to traditional, mono- specific, legume service shade tree canopies; and (2) to determine the production potential of ten cocoa clonal bi-crosses under these shade tree species. Within each site, shade tree species did not influence dry cocoa bean yield nor pod counts (total number of pods produced, number of healthy pods harvested, pod losses due to monilia (Moniliophthora roreri), black pod (Phytophthora palmivora) or other causes—birds and squirrels in this study-, and total pod losses). Significant differences were found between cocoa bi-crosses for both cocoa bean yield and pod counts. Sites differed only in terms of total pod losses (43% in CL; 54% in CT) and their causal factors (mainly monilia in CL; both monilia, squirrels and birds in CT). At CT, all timber tree species grew rapidly, reaching 30-34 cm dbh, 17-25 m total tree height and 97-172 m 3 ha -1 total stem volume (age 10 years). Timber species should be promoted for the shade component of cacao plantations given their potential production and the fact that their presence did not negatively affect cocoa yields.