Last week, Karolina, Michaela and Albin, went up to Mezyk/Poland to set up the instrumentation for a joint COS/CO2 flux and chlorophyll fluorescence campaign over a Scots Pine forest. The idea of the campaign is to quantify GPP during the “spring awakening” of photosynthesis of this evergreen species and use active and passiv chlorophyll fluorescence to diagnose functioning of the electron transport chain and evaluate the potential of sun-induced chlorophyll fluorescence as a proxy for GPP.