The Interplay Between Carbon Storage, Productivity, and Native Tree Density of Agroforestry Systems

Agroforestry has been widely suggested as a tool for storing carbon while also providing other ecosystem services like food and income production. A greater understanding of how carbon storage in agroforestry systems varies, and particularly how it is intertwined with the productivity of these systems, could enable farmers and policymakers to make changes that simultaneously increase carbon storage and alleviate poverty. In this study, we used allometric equations to evaluate the carbon storage in the biomass of two complex agroforestry systems in Bali, Indonesia—rustic where a native tree canopy is still present, and polyculture where all native trees have been removed, and the canopy consists only of cropping trees. We then compared these figures to that of a nearby primary forest and linked carbon storage to productivity for both agroforestry systems. We found that the primary forest (277.96 ± 149.05 Mg C ha −1 ) stored significantly more carbon than either the rustic (144.72 ± 188.14 Mg C ha −1 ) or polyculture (105.12 ± 48.65 Mg C ha −1 ) agroforestry systems, which were not significantly different from each other. We found productivity and carbon storage to be significantly positively correlated with each other within the polyculture system but not within the rustic system. We also found that for the rustic system, an increase in the density of native trees is accompanied by an increase in carbon storage, but no significant change in productivity. Consequently, we conclude that within the rustic system, carbon storage can be increased or maintained at a high value by the preservation and encouragement of large native trees, and that this need not necessarily result in a decrease in productivity.