Net greenhouse gas balance of fiber wood plantation on peat in Indonesia

Tropical peatlands cycle and store globally significant amounts of carbon in their soil and biomass. Climate and land-use change alter greenhouse gas (GHG) fluxes of tropical peatlands, but the magnitude of these changes remains highly uncertain owing to limited measurements. We measured net ecosystem exchanges of carbon dioxide (CO₂) and methane (CH₄) as well as soil nitrous oxide (N₂O) fluxes between mid-2016 and mid-2022 from Acacia crassicarpa plantation, degraded forest and intact forest within the same peat landscape to represent land-cover change trajectories in Sumatra, Indonesia. Here we report the first full plantation rotation GHG balance investigation undertaken in any fiber wood plantation on peatland globally. The Acacia plantation was found to have lower GHG emissions than the degraded peatland, which had a similar mean groundwater level, despite more intensive land-use. The GHG emissions from the Acacia plantation over a full plantation rotation (38.3 ± 4.8 tCO₂-eq ha⁻¹ yr⁻¹, average ± standard deviation) were two times higher than those from the intact forest (20.1 ± 3.7 tCO₂-eq ha⁻¹ yr⁻¹), but only around half of the current IPCC Tier 1 emission factor for this land-use. Our results should help to reduce the uncertainty in the estimation of GHG emissions from globally important ecosystems, provide a complete estimate of the impact of land-use change on tropical peat, and develop science-based peatland management practices that help to minimize GHG emissions.