Carbon stocks, emissions, and aboveground productivity in restored secondary tropical peat swamp forests

Abstract

Tropical wetlands such as peat swamp forests (PSFs) have been known globally as one of the carbon (C)-rich ecosystems. However, there is still a lack of understanding on the C cycle in PSFs, especially in association with land use and cover changes (e.g., ecosystem degradation and restoration). This study presents the C stocks, removals, and emissions dataset, as well as the determining factors from an early restoration stage of secondary tropical PSFs in Central Kalimantan. We assessed various biophysical parameters such as forest structure, above-and belowground C-stocks, aboveground primary productivity, total and heterotrophic soil respirations, and groundwater level (GWL). We found that tree density varied from 1200 to 1825 trees per hectare (ha) across the plots, whereas the mean of stand basal area was 32.86 ± 4.72 m 2 ha −1 . Mean ecosystem C stocks in the study site was 1752 ± 401 Mg-C ha −1 , of which 93% was stored in belowground organic peat soils. A mean aboveground litterfall production of 4.6 ± 0.5 Mg-C ha −1 year −1 and biomass C sequestration through tree diameter increment with 2.7 ± 0.5 Mg-C ha −1 year −1 was obtained. We observed slightly larger portion of annual mean total soil respiration with 14.2 ± 1.1 Mg-C ha −1 year −1 than heterotrophic respiration 11.1 ± 0.9 Mg-C ha −1 year −1 , emphasizing the lower contribution of autotrophic respiration from the belowground rooting system. Findings imply that further conservation management efforts through ecosystem restoration may preserve C stored and enhance C input in PSFs substantially, and could be potentially included in national climate change mitigation strategies.

People-Centric Nature-Based Land Restoration through Agroforestry: A Typology

“…Peat landscapes-Limited in area but now recognized in Congo and Amazon basin beyond their better-studied examples in Southeast Asia, they are disproportionately important in terrestrial carbon storage. Peat domes and lowland peat areas developed where drainage was restricted, and a year-round level of water saturation reduced organic matter decomposition to rates below the annual above-and belowground inputs [133]. Current understanding is that restoration focus should be on the peatland hydrological units (from dome to the river) essential for the continued function of peat domes including riparian zones that are not classified as peat soils themselves, spanning all land from river to river across the dome [134,135].…”

Land-use change and greenhouse gas emissions in the tropics : Forest degradation on peat soils

“…Site-scale R s at the intact site (11.4 ± 2.3 Mg C ha -1 yr -1 , Table 5.4) is in line with the 12.9 ± 2.1 Mg C ha -1 yr -1 average for PSFs of Southeast Asia , and more recent results from Indonesian primary and secondary PSFs of 12.3 ± 0.8 Mg C ha -1 yr -1 in (Swails et al, 2019), or 14.2 ± 1.1 Mg C ha -1 yr -1 (Saragi-Sasmito, Murdiyarso, June, & Sasmito, 2018). The moderately degraded site had a R s that was 47 -61% lower than in the other sites.…”

Tropical peatlands under siege: the need for evidence-based policies and strategies

“…where Ra is autotrophic respiration and Rh is heterotrophic respiration. Separating Rh from the total respiration reported in this issue (Murdiyarso et al 2018;Saragi-Sasmito et al 2018) is a useful approach to estimating NEP when combined with separate estimates of NPP. The latter is a close approximation to total ecosystem carbon balance, once other loss terms such as DOC export and loss of other gasses (e.g., CH 4 ) are accounted for.…”

“…These ambitious top-down policies need the scientific community to help guide the policy to meet the multiple objectives envisioned, including GHG emission reduction. Multiple studies in this issue generated data that can be used to refine emission factors (e.g., Murdiyarso et al 2018;Basuki et al 2018;Saragi-Sasmito et al 2018;, which are critical to quantifying the importance of tropical peatlands in global GHG budgets. The data reported in this special issue enrich existing information, including the published emission factors in the Wetland Supplement of the IPCC guidelines (IPCC 2014).…”