The importance of shade trees in promoting carbon storage in the coffee agroforest systems

Abstract

Mitigation of CO₂ atmospheric emission rates is partially accomplished through carbon storage in ecosystems, including agricultural systems. In particular, agroforestry systems have been cited as important current and potentially future depositories for carbon. Coffee is produced on substantial areas of tropical lands, traditionally incorporating shade trees as part of the system, but recently having seen much conversion to so-called sun coffee, largely absent of shade trees. Taking the coffee production region of Puerto Rico as a case study, we estimated carbon (C) stock on 68 coffee farms in the Cordillera Central region of Puerto Rico. Total farm carbon was determined by combining carbon content in the soil, shade trees and the main crops (coffee, plantain and citrus). We note that 38 of the farms used in this study incorporated shade trees, 30 did not. Farms that included shade trees had larger overall pools of C, with shade trees accounting for almost all the variability in C storage, as the other pools of carbon measured in this study were relatively constant from farm to farm. This case study demonstrates that adopting agroforestry practices on coffee farms (i.e., maintaining and incorporating shade and fruit trees) could contribute to the reduction of the world’s carbon footprint, given the importance and extent of this agroecosystem type.