Below-ground responses of silver birch trees exposed to elevated CO2 and O-3 levels during three growing seasons
Field-growing silver birch (Betula pendula Roth) clones (clone 4 and 80) were exposed to elevated CO2 and O-3 in open-top chambers for three consecutive growing seasons (1999-2001). At the beginning of the OTC experiment, all trees were 7 years old. We studied the single and interaction effects of CO2 and O-3 on silver birch below-ground carbon pools (i.e. effects on fine roots and mycorrhizas, so