Monitoring the effect of rising carbon dioxide (CO) concentrations and climatic changes on Europe's forests is the aim of a collaborative project across eight European countries and Australia. The project is jointly funded by the Forestry Commission of UK and the European Union under the Environment and Climate Programme 1994-1998. Presently, researchers are observing the effect of increased C02, ozone and drought on the growth of oak, ash and Scots pine at Headley Nursery in Hampshire, UK. They am measuring photosynthesis in the saplings of these plants, which are grown in open-top glazed chambers (Spectrutn, No 256).