Seasonal dynamics of stem N2O exchange follow the physiological activity of boreal trees
Katerina Machacova1, Elisa Vainio2,3, Otmar Urban4
1Global Change Research Institute of the Czech Academy of Sciences, Belidla 4a, CZ-60300, Brno, Czech Republic. machacova.k@czechglobe.cz.
Abstract:
The role of trees in the nitrous oxide (N2O) balance of boreal forests has been neglected despite evidence suggesting their substantial contribution. We measured seasonal changes in N2O fluxes from soil and stems of boreal trees in Finland, showing clear seasonality in stem N2O flux following tree physiological activity, particularly processes of CO2 uptake and release. Stem N2O emissions peak during the vegetation season, decrease rapidly in October, and remain low but significant to the annual totals during winter dormancy. Trees growing on dry soils even turn to consumption of N2O from the atmosphere during dormancy, thereby reducing their overall N2O emissions. At an annual scale, pine, spruce and birch are net N2O sources, with spruce being the strongest emitter. Boreal trees thus markedly contribute to the seasonal dynamics of ecosystem N2O exchange, and their species-specific contribution should be included into forest emission inventories.
Related Concept Videos
Biological Clocks and Seasonal Responses
Regulation of Transpiration by Stomata
Inorganic Nitrogen Assimilation
The Calvin Benson Cycle
Xylem and Transpiration-driven Transport of Resources
Meristems and Plant Growth


