At present there are about 12 micrometeorological tower sites north of 60°N in Sweden that use eddy covariance techniques to measure the exchanges of carbon dioxide, water vapor, energy, and at some sites methane between terrestrial ecosystem and atmosphere on a long-term and continuous basis (Table 5, ##5, 9, 11, 12, 15, 16–22). Among these tower sites, Norunda is the oldest and most complete complete (Table 5, #5). Three towers are in use at Rosindal, 70 km northwest of Umeå, in full-scale nitrogen and carbon dioxide experiments (Table 5, #12). In addition, one site is located at Zackenberg on Greenland (Table 5, #22). At the sites, data on vegetation, soil, and meteorological and hydrological conditions are also collected. The Swedish sites are integrated in the international Fluxnet program that assembles more than 400 eddy covariance sites around the world in an effort to better understand land surface – atmosphere interaction and its role in global change. The Swedish micrometeorological towers are presently financed by research councils, viz. Swedish Research Council (VR) and Formas, EU and university faculties. A European research infrastructure for flux measurements, the Integrated Carbon Observation System (ICOS) is being planned and includes Sweden as one of the participating nations.