The intermittent and synchronized production of a large amount of flowers and seeds is called masting or mast seeding. Applying recent advances in molecular and genetic studies about flowering time control to masting species is increasingly useful to unravel the underlying mechanism of masting. To uncover the molecular basis for masting, we performed global gene expression analyses in a typical masitng species, Fagus crenata Blume. Our analyses unraveled the non-intuitive relationship between seasonal environment and expression profiles of genes involved in photoperiod and circadian clock pathways. The most striking result was the interaction between nitrogen transporter activity and expression of floral pathway integrator, FLOWERING LOCUS T. This result supports our previous finding that nitrogen is the key regulator of flowering in F. crenata. Our results will be discussed from the view point of nitrogen cycling and plant-soil feedback.