ESA generally organises airborne campaigns to support the preparation and validation of ESA's Earth Observation space missions. Within this context the main goal of the SIFLEX campaign was to understand whether solar induced fluorescence measurements may someday be used to monitor and map the photochemical activity of boreal forests from space. Specific objectives of the campaign were: to measure and quantify solar-induced fluorescence flux in A and B oxygen absorption bands during spring thaw in Boreal forest, to collect complimentary measurements for fluorescence interpretation and radiative modelling purposes e.g. spectral reflectance, solar irradiance etc, to collect CO2 flux dataset for study of linkage between photosynthetic activity indicators (e.g. fluorescence and PRI) and CO2. The main participating institutes in the campaign were LURE (Laboratoire pour l'Utilisation du Rayonnement Electromagnetique), in Paris, France, the University ofValencia, Valencia, Spain and FMI (Finnish Meteorological Institute) in Helsinki, Finland. The campaign took place at the Sondankyla Geophysical Observatory in northern Finlandbetween April 30 and June 10, 2002 and covered the main period of spring recovery of photochemical activity of Scots pine trees. In order to meet the study objectives a vast array of complimentary measurements were carried out during this time. These included solar induced fluorescence of the forest canopy at different scales using instruments developed in-house by LURE, solar radiation measurements to determine and quantify illumination conditions, thermal measurements to measure heat loss by the pine needles and reflectance measurements to obtain a broader picture of the status of the trees. Essential information about the condition of the boreal trees through carbon dioxide, water vapour, air temperature and humidity was collected from a 50-metre high micrometeoological tower adjacent to the experiment site. As a result of the campaign researchers gained experience in the characterisation of Boreal forests for remote sensing studies and over 1 Gigabyte of valuable data was collected. This data is currently being documented and organised into a database which will let researchers easily access and cross-compare the measurements from different instruments providing a complete picture of the radiation properties of boreal forests. The database will be instrumental in helping define novel accurate ways of measuring photosynthesis from space, for instance through solar induced fluorescence, and will help in the verification that such signals are suitable for observation from space.