Abstract: The fluxes of wet nitrogen deposition inside and outside Tiantong forest were observed for 2 years (from March 2011 to February 2013), basing on Ionexchange resin method, to examine the composition and the seasonal dynamics of wet nitrogen deposition in Tiantong forest. The results showed that: (1) The monthly fluxes of nitrate nitrogen inside and outside forest were 0.22~3.73 kg·N/(hm2·month) and 0.13~2.85 kg·N/(hm2·month), respectively, which both had higher fluxes in autumn and winter, while lower fluxes in summer. The 〖JP3〗monthly fluxes of ammonium nitrogen inside and outside forest were 0.17~1.35 kg·N/(hm2·month) 〖JP〗and 0.21~1.44 kg·N/(hm2·month), respectively. The monthly fluxes of ammonium nitrogen were lower in spring than in other seasons. (2)The nitrate nitrogen deposition fluxes were lower than ammonium nitrogen deposition fluxes in spring and summer, while higher in autumn and winter. Moreover, the average ratio of nitrate nitrogen to ammonium nitrogen was 0.9, whatever inside and outside forest. (3) The wet nitrogen deposition fluxes were higher in autumn and winter inside and outside forest, respectively, resulted from the influences of monsoon climate, typhoons in summer and the farming activities in Tiantong region.(4) The annual wet nitrogen deposition fluxes inside and outside forest were 18.86 kg·N/(hm2·a) and 17.51 kg·N/(hm2·a), respectively.

Key words: nitrogen deposition, ionexchange resin method, Tiantong, forest