Climate change is often expected to result in migration of tree species and forest expansion. This is based mainly both on paleoecological studies as well as climate-envelope modelling, both of which have their strengths and limitations. Some observational studies have also begun to document expansion and migration. But these processes could be limited by both climatic and non-climatic factors associated with global change. Basic questions remain unknown for many ecosystems: How fast will migration/expansion occur? What factors and processes may limit or facilitate it? The role of multiple stressors and disturbance in forest expansion and migration is still poorly understood. This symposium aims to gather a diversity of scientists (rank, geographic location, etc.) working on forest migration and expansion from different perspectives (field studies, modelling etc.). The goal is to 1) integrate observational and modelling studies, 2) inform the ecological community of the state-of-the art of this science, and 3) to exchange and flesh out ideas in order to direct future research.