Specific questions to be addressed are:

The mechanistic and process-based responses of trees and tree communities to global change, particularly in response to the predicted increase of atmospheric [CO₂], will be crucial in determining the ability of planted and natural forests to sequester carbon at the global scale. Despite the key role played by trees and forests within the terrestrial biosphere, we still have very limited information on the total responses of agro-forestry and forest systems to enhanced [CO₂] because of the complex web of possible interactions

Is above-ground biomass production stimulated during a long-term exposure of a fast-growing tree stand to elevated [CO₂] and will C-allocation patterns change in relation to N-treatment and genotypic differences?

Does the exposure to elevated [CO₂] affect both leaf cell production and expansion?

Will elevated [CO₂] increase leaf area duration and LAI of poplar stands because of a better adaptation of foliage to shade?

Does elevated [CO₂] decrease leaf stomatal conductance but not canopy transpiration?

Will fine roots production and turnover increase in response to [CO₂] enrichment, specifically in the low N-treatment?

Will elevated [CO₂] exposure increase carbon accumulation into the soil and nitrogen utilization efficiency?

Will insects performance decline under elevated [CO₂] and will pathogens virulence be differently affected in biotrophic vs. weakness fungi?