Online Eddy-covariance tower measurements: Fluxes of carbon dioxide, water and energy between the ecosystem and the atmosphere are measured at the intensive study sites Ruukki and Qvidja. Both sites are equipped with a three-axis sonic anemometer2 and an enclosed-path infrared gas analyser3.. Gaps in the flux data are filled using an algorithm of FMI; please note that the values are provisional and will be subject to further quality control. For more information on the Eddy-covariance data, please contact the PIs of the intensive sites.