Tree stems are a net source of CH 4 and N 2 O in a hemiboreal drained peatland forest during the winter period

作者：Reti Ranniku, Thomas Schindler, Jordi Escuer-Gatius, Ülo Mander, Kateřina Macháčová, Kaido Soosaar · 发表于：Environmental Research Communications · 年份：2023 · DOI：10.1088/2515-7620/acd7c7 · 被引用次数：14 · 研究领域：Peatlands and Wetlands Ecology、Climate change and permafrost、Fire effects on ecosystems

Abstract Nutrient-rich northern peatlands are often drained to enhance forest productivity, turning peatland soils into sinks of methane (CH 4 ) and sources of nitrous oxide (N 2 O). However, further attention is needed on CH 4 and N 2 O dynamics during the winter period to fully understand the spatio-temporal variability of fluxes. Besides soil, tree stems can also emit CH 4 and N 2 O. However, stem contribution is not considered in most biogeochemical models. We determined the temporal dynamics of winter-time CH 4 and N 2 O fluxes in a drained peatland forest by simultaneously measuring stem and soil fluxes and exploring the relationships between gas fluxes and soil environmental parameters. During sampling (October 2020–May 2021), gas samples from Downy Birch ( Betula pubescens ) and Norway Spruce ( Picea abies ) trees were collected from different tree heights using manual static chambers and analysed using gas chromatography. Soil CH 4 and N 2 O concentrations were measured using an automated dynamic soil chamber system. Tree stems were a net source of CH 4 and N 2 O during the winter period. The origin of stem CH 4 emissions was unclear, as stem and soil CH 4 fluxes had opposite flux directions, and the irregular vertical stem flux profile did not indicate a connection between stem and soil fluxes. Stem N 2 O emissions may have originated from the soil, as emissions decreased with increasing stem height and were driven by soil N 2 O emissions and environmental parameter...