Tree dynamics often unfold over many years, such that trends are only revealed by tracking a large number of individuals through time. Changes in forest communities depend on complex interrelationships between the species present, physical template, and stochastic establishment and mortality events. This session will explore the commonalities and differences among different forest types throughout the world. Speakers will use examples from large permanent plots, predominantly in those forty affiliated with the Smithsonian Center for Tropical Forest Science (http://www.ctfs.si.edu/). The emphasis is on comparative dynamics elucidating ecological principles with broad applicability. Several new datasets from large, permanent forest dynamics plots situated in temperate and tropical forests around the globe have recently become available. The Smithsonian-initiated, consistent methodology for large permanent plots established throughout the world allows novel comparisons of dynamics across ecosystems. These datasets also facilitate novel tests of ecological theory which were previously only possible at a few locations. Speakers in this session will present new empirical results from a diverse array of sites. The emphasis for this session is on comparative studies that (1) elucidate commonalities and associated ecological principles with broad generality, and conversely, that (2) reveal divergent or individualistic patterns among sites, suggesting a hierarchal structure to the underlying mechanisms that regulate forest dynamics. The aggregate outcomes of this session therefore include validation of broadly applicable ecological principles, as well as novel results which motivate future theoretical and empirical work.