ABSTRACT
Many papers in this volume emphasize the potential importance of global change to mountain ecosystems. The possible effects of global change on Swiss forests have been examined using a modelling approach (Brzeziecki et al., 1993; Bugmann and Fischlin, this volume). While models provide a valuable insight into the possible changes that might occur given changing environmental conditions, it is important that the predictions are backed up by observation. These are not only necessary for the initial model calibration, but enable the model to be tested and, if necessary, adjusted, through time. A major problem in relation to studies of changes in forests is the scarcity of basic data on forest ecosystem processes which can be used to calibrate the models (Wiersma et al., 1991). In addition, there are few data available on changes in forest ecosystem processes in relation to environmental change. These provide important reasons for the field observation of processes acting in forest ecosystems.
