Forest ecosystems are receiving substantial nitrogen (N) deposition due to human activities. However, there were rare estimations on fluxes of dissolved organic nitrogen (DON) and contribution of snowfall on N deposition. Moreover, N fluxes in internal N cycle of forest ecosystems are necessary to identify final N deposition to soil layer. In this study, bulk precipitation, stemflow and throughfall were measured in the Takayama forest during three years. 11.2 ± 1.83 kg N ha^–1 yr^–1 N input into the study site with great contribution of DON (71 %). Snowfall fluxes contributed up to 46 % of total N input with great year-to-year variation related to amount of snowfall (2.08–5.52 kg N ha^–1 yr^–1). When N deposition passed through canopies, tree canopy released DON (2.11 ± 0.42 kg N ha^–1 yr^–1) but consumed NO₃ + NO₂–N (0.73 ± 0.19 kg N ha^–1 yr^–1). In contrast, understory bamboo canopy released dissolved inorganic nitrogen (0.35 ± 0.44 kg N ha^–1 yr^–1). This study appealed that DON and snowfall should not be neglected to evaluate total N deposition into forest ecosystems. Canopy process is important for internal N cycle of forest ecosystems.