The use of controlled grazing by large herbivores as a research and management tool in forest systems is reviewed, with particular focus on exclosure-based studies of plant–animal interactions within north-west Europe. Controlled grazing studies have revealed that large herbivores (wild and domestic) have a substantial influence on forest composition and dynamics. We review current knowledge and highlight the deficiencies and potentials for new research, in relation to specific areas identified as of key importance in forest dynamics.