Effects of tropical forest conversion into oil palm plantations on nitrous oxide emissions: A meta-analysis

Oil palm plantations have dramatically expanded in tropical Asia over the past decades. Although their establishment has been projected to increase nitrous oxide (N2O) emissions, earlier reports have shown inconsistent results. This study analyzed these previously published data to compare N2O emissions in oil palm plantations to reference forests. A linear mixed-effects model was used to examine the significance of the effect of establishing oil palm plantations on N2O emissions, rather than to calculate mean effect sizes because of limitations in the data structure. The results indicated that N2O emissions were significantly greater from oil palm plantations than from reference forests, as expected. This is the first study to report the effect of oil palm plantations on N2O emissions by synthesizing previously published data. To quantify the size of this effect, additional studies with frequent and long-term monitoring data are needed.