Forest ecosystem and climate and environmental change - what does this mean for biosphere-atmosphere exchange of atmospheric trace gases?

Keynote for the IUFRO Landscape Ecology Conference “Sustaining ecosystem services in forest landscapes”, 23-30 August 2015, Tartu, Estonia 

Forests ecosystem cover approx. 30% of the world terrestrial surface, or around 4 billion hectare. Forests do not only function as major sinks (and sources) for atmospheric CO₂ but also as significant sources and sinks of other environmental important atmospheric trace gases, namely NO, N₂O and CH₄. The importance of forests as regulators of atmospheric concentrations of these trace gases is undebated, but how this function might change in view of on-going climate and environmental changes (e.g. atmospheric N deposition and increases in atmospheric CO₂ concentrations) remains a matter of debate, which hampers to analyse and predict possibly feedbacks. E.g. increases in temperature and atmospheric CO₂ concentrations might favour denitrification and forest soil N₂O emissions, while declining precipitation or more erratic rainfall might result in the opposite. Providing a set of examples I will discuss current knowledge and research perspectives to better understand the future role of forests as regulators of the atmospheric composition.

Institute of Meteorology and Climate Research, Atmospheric Environmental Research (IMK-IFU), Karlsruhe Institute of Technology, Garmisch-Partenkirchen, Germany