Extreme climate events such as droughts and floods are predicted to increase in the future. Hereby, the hydrological regime in ecosystems alters and therefore influences the biochemical processes controlling the greenhouse gas (GHG) flux.
A multinational team of researchers from Global Change Research Institute of the Czech Academy of Sciences and the University of Tartu/Estonia investigated the important effect of short-term flooding on fluxes of methane (CH4) and nitrous oxide (N2O) from trees in riparian systems. The studied results were published in Scientific Reports (a Nature-research journal) in February 2020. For the experiment, the researchers “flooded” a mature grey alder (Alnus incana) forest in Estonia. Hereby, the gas exchange was measured simultaneously from soil (automatically) and tree stems (manually) at different stem heights. The tree stems and soil surface were net sources of N2O and CH4 during the flooding and the emissions of both gases increased with the flooding. Moreover, CH4 emissions enormously raised also after the flooding. N2O fluxes from tree stems were much lower, whereas CH4 emissions were much higher than from soil after the flooding. The flooding experiment indicated soil water and nitrogen content as the main controlling factors of the fluxes. The stems contributed up to 88% of CH4 emissions from soil-tree stem continuum in flooding and post-flooding period, whereas soil N2O fluxes dominated during all periods. The results underline the importance of trees within the GHG exchange in forests, especially, but not limited to future climate change scenarios.
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Schindler T, Mander U, Machacova K, Espenberg M, Krasnov D, Escuer-Gatius J, Veber G, Pärn J, Soosaar K (2020) Short-term flooding increases CH4 and N2O emissions from trees in a riparian forest soil-stem continuum.
Scientific Reports 10, 3204. https://doi.org/10.1038/s41598-020-60058-7