part I. Introduction into the scope and structure of the book -- part II. Interactions between trace gases, climate change, and vegetation -- part III. Significance of biotic processes in forest ecosystem response -- part IV. Mechanistic and diagnostic understanding for risk assessment and up-scaling -- part V. Global dimension of air pollution as part of climate change -- part VI. The potential of "supersites" for research on forest ecosystems -- part VII. Knowledge transfer and socio-economic aspects -- part VIII. Synopsis.