Tree diversity and stored carbon in cocoa (Theobroma cacao L.) agroforestry systems in Soconusco, Chiapas, Mexico

Introduction: Cocoa (Theobroma cacao L.) yields in Chiapas, Mexico remain low, but can be improved with agroforestry designs that consider tree composition to ensure diversity and carbon sequestration. Objective: To determine tree diversity and stored carbon at three elevational levels of cocoa agroforestry systems in Soconusco, Chiapas.  Materials and methods: Representative 50 x 20 m plots were established at three elevational levels (0 to 50 m, 51 to 100 m and ≥101 m). Species were counted and classified taxonomically. Diameter at breast height, height of each species, diversity, similarity between pairs of heights, and carbon storage were estimated. Results and discussion: Richness was 35 tree species selected by the producers to shade the cocoa crop. These were grouped into 32 genera and 22 families. Abundance was 199 trees, with abundance per plot and diversity being the highest at ≥101 m. Lower diversity was associated with heights with less equity between abundance and richness. Carbon stored in aerial biomass ranged from 224.9 to 362.1 Mg·ha-1; the amount was highest at lower elevations (0 to 50 m). Conclusions: Agroforestry systems had medium to high diversity. Species distribution, by elevational level, responds to the interests of the producers and to the composition of the natural forest. The amount of stored carbon was high, due to the abundance, richness and dominance of the species.