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ORIGINAL RESEARCH article
Front. For. Glob. Change
Sec. Forest Soils
Volume 8 - 2025 | doi: 10.3389/ffgc.2025.1528440
A synthesis of freshwater forested wetland soil organic carbon storage
Provisionally accepted- 1 Environmental Laboratory, U.S Army Engineer Research and Development Center, Vicksburg, MS, United States
- 2 Wetland and Aquatic Research Center, U.S. Geological Survey, Lafayette, LA, United States
- 3 Construction Engineering Research Laboratory, U.S. Army Engineer Research and Development Center, Champaign, IL, United States
Freshwater forested wetlands account for ~76% (918 M ha) of the total global wetland extent. However, freshwater forested wetlands are difficult to distinguish from upland forest due to canopy coverage, the abundance of wetland-nonwetland mosaics, seasonal hydropatterns, and fewer readily observable connections to large surface water bodies relative to marshes and other emergent habitats. Therefore, freshwater forested wetland ecosystems are often misclassified as upland forests in carbon accounting models, underestimating soil organic carbon (SOC) storage.This study highlights freshwater forested wetland SOC accounting challenges and presents SOC densities/stocks from a global literature synthesis across different freshwater forested wetland types. We reviewed 374 forested wetland articles, compiling and calculating carbon densities by depth from 90 freshwater forested wetland studies to construct a database of 334 study sites including nine countries. The median (± median absolute deviation) SOC stock was 91.2 ± 46.4 Mg C ha -1 and 235.3 ± 125.6 Mg C ha -1 in the top 30 cm and 100 cm of soil, respectively. The tidal freshwater forested wetland had highest SOC stock (341.6 ± 98.4 Mg C ha -1 ) in the upper 100 cm soil profile followed by rainforest (285.6 ± 75.8 Mg C ha -1 ), non-tidal swamps (229.3 ± 120.4 Mg C ha -1 ), and floodplain forested wetlands (176.6 ± 84 Mg C ha -1 ). Within the conterminous United States forest type groups, the Tsuga/Picea group had the highest median SOC stocks (353.6 ± 82.9 Mg ha -1 ) in the top 100 cm of soil followed by Quercus/Pinus (246.6 ± 82.3 Mg ha -1 ) and Quercus/Liquidambar/Taxodium (207.9 ± 87.7 Mg ha -1 ) groups, likely driven by variability in litter degradability, wetland hydroperiod, geomorphic positions, and regional climatic factors. This literature synthesis highlights SOC accounting in freshwater forested wetland carbon pools when estimating carbon stocks and fluxes. Results can be used to improve carbon modeling outcomes, as well as inform regional, national, and global management of wetland carbon resources.
Keywords: carbon stock, Carbon accounting, Wetland soil, carbon cycling, Geomorphic settings, Forest type groups
Received: 14 Nov 2024; Accepted: 20 Mar 2025.
Copyright: © 2025 Sapkota, Berkowitz, Stagg and Busby. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Jacob F. Berkowitz, Environmental Laboratory, U.S Army Engineer Research and Development Center, Vicksburg, MS, United States
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