Abstract
This chapter reviews the various interactions between tree processes and the environment in the context of observed and expected environmental changes. The chapter begins with the influences of the ubiquitous atmospheric increases in CO2 concentration on leaf photosynthesis and respiration, followed by the expected influences on tree processes. Influences of increasing incidence of drought, increased temperatures and extreme events are then discussed with respect to leaf and tree level processes. Specific attention is given to hydraulic architecture, tree growth and water use efficiency, and species differences in water relations and canopy structure across Europe. The chapter ends with a brief review of canopy-atmosphere interaction and forest influences on climate.