Aim A regional model of vegetation dynamics was enhancedto include biogeochemical cycling of nitrogen and was thenapplied to a forest transect in east China (FTEC) in order to investigatethe responses of the transect to possible global change. Location Eastern China. Methods Biomass and nitrogen concentration of green andnongreen portions of vegetation, moisture contents of threesoil layers, and total and available soil nitrogen are includedas state variables in the enhanced model. The model wasparameterized and validated against field observations ofbiomass, productivity, plant and soil nitrogen concentration,nitrogen uptake, a vegetation index derived from satelliteremote sensing and digital maps of vegetation and soil distributionsalong a forest transect in eastern China (FTEC). The model was applied to FTEC in order to investigate theresponsive characteristics of the ecosystems to global climaticchange. Scenarios of climate change under doubled CO2produced by seven general circulation models (GCM) wereused to drive the model. Results The simulations indicated that the model is capableof simulating accurately potential vegetation distribution andnet primary productivity under contemporary climatic conditions.The simulations for GCM-projected future climatescenarios with doubled atmospheric CO2 concentrationpredicted that broadleaf forests would increase, but coniferforests, shrubs and grasses would decrease; and that deciduousforests would have the largest relative increase, but evergreenshrubs would have the largest decrease. Conclusions The overall effects of doubling CO2 and climaticchanges on FTEC were to produce an increased net primaryproductivity (NPP) at equilibrium for all seven GCM scenarios.The inclusion of nitrogen dynamics in the model imposesmore constraint on the responses of FTEC to climatic changethan the previous version of the model without nitrogendynamics. Temperature exerts a stronger control on NPPthan precipitation, as indicated by the negative correlationsbetween NPP and temperature. The southern portion of FTEC,at latitudes less than 33