forest dynamics arise from three demographic processes simultaneously, namely recruitment, mortality and growth, all of which are expected to accelerate for the boreal forest under future climate change. tree species diversity, however, is hypothesized to mitigate the impacts of climate change on the rates of these demographic processes. at the same time, understanding the generation and maintenance of tree species diversity is a historical challenge and requires examining multiple demographic dynamics simultaneously. the purpose of this dissertation is to investigate the complex relationship between tree demographics and diversity under the influence of climate change through spatial analysis of 173 permanent sample plots in the boreal forest of manitoba, canada, at the individual-tree level. a mapped dataset of individual stems that were repeatedly measured from 1986 to 2010 forms the basis of three studies. [...]