Periodical mass seed production, called masting, effects forest ecosystem and food web dynamics. Despite its importance, masting is not included in forest vegetation models, so future changes due to global warming in masting frequency and intensity are not evaluated.
   To address this problem, this study modified an individual based vegetation model to include masting and validated it using a temperate deciduous-conifer mixed forest in Hokkaido.
   Three major masting theories were tested: the resource budget, pollen limitation, and weather pattern hypotheses. The models were optimized for three parameters: daily storage of masting resources, threshold limit for masting, and cost of acorn production in relation to the cost of flowers.
   The results showed that high values of masting storage and low values of threshold both aborted tree survival, and only a few parameter combinations did not impede tree growth. The coefficient of variation calculated from seed production was lower than observed at the validation site, but masting frequency and pattern was similar. By using future climate data, the model developed here can simulate the effects of global warming on masting and help to mitigate potential negative impacts on the forest ecosystem and nature-human interactions.