Carbon and water balance of an afforested shallow drained peatland in Iceland

• Published in: Forest Ecology and Management
• Main Authors: Bjarnadóttir, Brynhildur, Aslan Sungur, Guler, Sigurðsson, Bjarni Diðrik, Kjartansson, Bjarki T., Óskarsson, Hlynur, Oddsdottir, Edda S., Gunnarsdottir, Gunnhildur E., Black, Andrew
• Other Authors: Faculty of Environmental and Forest Sciences, University of Akureyri
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2021
• Subjects: Kolefni; Votlendi; Vatn; Carbon cycle; Drained wetland; Land-use change; Mitigation; Populus trichocarpa; Land-use changes; Forestry; Nature and Landscape Conservation; Management; Monitoring; Policy and Law; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/2978; https://doi.org/10.1016/j.foreco.2020.118861

Funding Information: This research was supported by the Energy Research fund of Landsvirkjun, the National Power Company of Iceland, with an additional support from the Iceland State Electricity. It also contributes to the Nordic CAR-ES project ( C entre of A dvanced R esearch on E nvironmental S ervices from Nordic Forest Ecosystems) and to the SNS 120 program (Nordic Forest Research on Anthropogenic greenhouse gas emissions from organic forest soils: improved inventories and implications for sustainable management). Publisher Copyright: © 2020 The Author(s) Drainage of peatlands increases the depth of the oxic peat layer and can turn them into a carbon (C) source to the atmosphere. Afforestation of drained peatlands could help to reverse this process since the trees may enhance C sequestration. We followed the C and water dynamics of an afforested drained peatland in S-Iceland during a 2 year period, during which the Black Cottonwood (Populus balsamifera ssp. trichocarpa) plantation was 23–25 year old. Net ecosystem exchange (NEE) of carbon dioxide (CO2) was measured with the eddy covariance method and C pools of trees and ground vegetation were measured using the stock change method. Lateral losses of dissolved and particulated organic C (DOC, POC) were estimated from weekly water-runoff samples. Unexpectedly, the afforested drained peatland was a strong sink of carbon during the two years, with an average NEE value of 714 g C m−2 yr−1. Only 0.5% of the total NEE was lost through lateral DOC and POC transport, leaving 710 g C m−2 yr−1 as the total net ecosystem production (NEP). Ca. 91% of the observed NEP could be explained by the annual biomass increment of the Black Cottonwood trees and 1.3% by the ground vegetation. This means that the remaining 7.5% of the total NEP most likely accumulated in peat soil and litter, contributing to the soil C stocks. The dormant-season CO2 emissions were unexpectedly low, which was explained by a high groundwater level at this drained site outside the ca. 5 months of the ...