Modeling vegetation carbon stock and soil greenhouse gas emission dynamics in undrained degraded peat swamp forests of Indonesia and Peru

Data on vegetation carbon storage and soil greenhouse gas (GHG) dynamics in degraded undrained peatlands, and their recovery timeframes, are limited. Additionally, despite their important extent across the tropics, these systems remain unconsidered by the Intergovernmental Panel on Climate Change guidelines for GHG inventories. We modified the existing DeNitrification DeComposition model to simulate undegraded and degraded undrained peat swamp forests in Indonesia and Peru. We simulated partial clearing for agroforestry and burning in Indonesia, and in Peru selective timber harvesting and Mauritia flexuosa palm cutting for fruit harvest. Based on model results, we derived peat onsite CO 2 , N 2 O, and CH 4 emission factors (EF), assessed timeframes for recovery of vegetation C stocks and peat GHG emissions, and investigated relationships among peat GHG fluxes and biophysical controls. Vegetation carbon stocks recovered 40 years after modeled disturbance in Indonesia, and 80 years post-disturbance in Peru. Simulated degradation increased the peat onsite CO 2 EF during the first decade post-disturbance by 557% and 121% in Indonesia and Peru, respectively, with recovery by the second decade post-disturbance at both locations. Degradation also induced an increase in soil N 2 O emissions in Indonesia (344%) and Peru (323%), with elevations persisting for four decades. As in field observations, simulated disturbances tended to raise CH 4 emissions in Indonesia and lower them in Peru, but not substantially. Temporal variations in modeled peat onsite CO 2 and N 2 O EF were linked to degradation-driven changes in soil C:N ratio, and for peat CH 4 fluxes to water table and soil moisture dynamics unrelated to disturbance. Our results suggest elevation of peat GHG emissions in these forests up to four decades after anthropogenic disturbances that need accounting in national GHG inventories. • We used the DNDC model to simulate degraded undrained tropical peat swamp forests. • Recovery of vegetation carbon stocks after disturbance required up to 80 years. • Degradation induced increases in peat CO 2 and N 2 O emissions persisting for four decades. • National greenhouse gas inventories should account emissions from these forests.