Methane emission from stems of European beech (<i>Fagus sylvatica</i>) offsets as much as half of methane oxidation in soil
Kateřina Macháčová, Hannes Warlo, Kateřina Svobodová, Thomas Agyei, Tereza Uchytilová, Petr Horáček, Friederike Lang
Abstract
Summary Trees are known to be atmospheric methane (CH 4 ) emitters. Little is known about seasonal dynamics of tree CH 4 fluxes and relationships to environmental conditions. That prevents the correct estimation of net annual tree and forest CH 4 exchange. We aimed to explore the contribution of stem emissions to forest CH 4 exchange. We determined seasonal CH 4 fluxes of mature European beech ( Fagus sylvatica ) stems and adjacent soil in a typical temperate beech forest of the White Carpathians with high spatial heterogeneity in soil moisture. The beech stems were net annual CH 4 sources, whereas the soil was a net CH 4 sink. High CH 4 emitters showed clear seasonality in their stem CH 4 emissions that followed stem CO 2 efflux. Elevated CH 4 fluxes were detected during the vegetation season. Observed high spatial variability in stem CH 4 emissions was neither explicably by soil CH 4 exchange nor by CH 4 concentrations, water content, or temperature studied in soil profiles near each measured tree. The stem CH 4 emissions offset the soil CH 4 uptake by up to 46.5% and on average by 13% on stand level. In Central Europe, widely grown beech contributes markedly to seasonal dynamics of ecosystem CH 4 exchange. Its contribution should be included into forest greenhouse gas flux inventories.