BIPHOREP (Biogenic VOC Emissions and Photochemistry in the Boreal Regions of Europe) is a multidimensional project, with an overall objective to measure, quantify and validate biogenic VOC emissions and to assess their importance for ozone formation in North Europe. BIPHOREP was initiated under the financial support by the Environment and Climate Programme of the European Commission. The project methodologies include measurements of biogenic emissions from individual plants using cuvettes and teflon bags and canopy scale flux measurements using micrometeorological methods. Two intensive field campaigns are carried out, the first (July-August, 1996) at Pallas, which is located in the northern boreal zone, and the second (summer, 1997) at Mekrijärvi, which is between the southern and middle boreal zones. Ambient air concentration measurements of biogenic VOCs and oxygenated compounds at these sites during an extended summer period are used to study the seasonal emission pattern. Emission estimates will be calculated using a canopy model and an extensive forest biomass inventory. Emission and photochemical modelling and measured ambient concentrations will be used to make a study of the effect of biogenic VOCs on the photochemical processes.