Long-term trajectory and temporal dynamics of tropical peat subsidence in relation to plantation management and climate

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

“…1). There was clearly a strong association during the study period between C loss, subsidence and droughts driven by regional climate extremes 26 . Our results indicate that even low-level or indirect human disturbance (for example, by means of climate change) can lead to C loss, highlighting the hydroclimatic vulnerability of C in forested tropical peatlands [13][14][15][16] .…”

“…However, plantation water management is not believed to have affected forest hydrology at the flux tower footprint in the study area. Previous analysis suggested that such effects occurred within 300 m of the plantation boundary 25 , and recent multivariate analysis indicates that subsidence in the interior forest is independent of distance from plantation canals 26 . This is further indicated by subsidence at rates of −1.4 cm year −1 (Extended Data Table 5 ) observed at sampling locations between 7 to 10 km from the active plantation edge (Fig.…”

“…A total peatland area of 7.8 million hectares is managed for agriculture and silviculture, of which more than one million hectares are under fibre wood (mostly A. crassicarpa) plantations 21 . Artificial GWL drawdown in agriculture and plantations on peatland exposes previously accumulated peat organic material to oxygen and promotes aerobic decomposition of organic C, resulting in carbon dioxide (CO 2 ) emissions 22,23 and associated land subsidence [24][25][26] . At present, the IPCC Tier 1 CO 2 EF 20 for short-rotation tree plantations on tropical peat is entirely based on the use of short-term measurements from the 3-8 years after drainage using subsidence 22 and soil-chamber 23 techniques.…”

A process-based model for quantifying the effects of canal blocking on water table and CO2 emissions in restored tropical peatlands

“…Furthermore, the impact of blocks on WTD would probably change in timescales of decades, which is closer to the typical lifespan of canal blocks (Ritzema et al, 2014;Dohong et al, 2018). When analyzing long-term scenarios, the effect of climate change in precipitation and evapotranspiration (Gallego-Sala et al, 2018;Wang et al, 2018;Cai et al, 2014;Pörtner et al, 2022), as well as peat subsidence (Evans et al, 2019;Hoyt et al, 2020;Evans et al, 2022) will need to be addressed. In order to have a more precise estimate of greenhouse gas emissions, future studies should take into account emissions of other compounds, such as methane and nitrous oxides.…”

“…However, the same mechanisms that make the drainage-based bioproduction economically valuable have severe environmental consequences. Drainage increases CO 2 emissions (Novita et al, 2021;Jauhiainen et al, 2012;Ishikura et al, 2018;Carlson et al, 2015), the rate of peat subsidence (Evans et al, 2022(Evans et al, , 2019Hooijer et al, 2012;Sinclair et al, 2020;Hoyt et al, 2020), fire risk (Miettinen et al, 2017;Kiely et al, 2021), nutrient release (Laurén et al, 2021a, b) and export to water courses (Nieminen et al, 2017), and decreases the peat substrate quality (Könönen et al, 2018).…”