Photo 1 (IMAGE) Helmholtz Centre for Environmental Research - UFZ Caption Quantifying gas exchange of various tree species / SMEAR II, Hyytiälä Forestry Station, University of Helsinki (Finland) Credit ©Juho Aalto Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.