A Distributed Forest Wetland Hydrologic Model(DFWHM) was constructed and used to examine water dynamics in the different climates of three different watersheds(a cold region,a sub-tropic region,and a large-scale watershed).A phenological index was used to represent the seasonal and species changes of the tree canopy while processes of snow packing,soil freezing,and snow and ice thawing were also included in the simulation.In the cold region,the simulated fall of the groundwater level in winter due to soil freezing and rise in spring due to snow and ice melting compare well with the observed data.Because the evapotranspiration and interaction of surface water and groundwater are included in the model,the modeled seasonal trend of the groundwater level in the sub-tropic region is in agreement with observations.The comparison between modeled and observed hydrographs indicates that the simulations in the large-scale watershed managed to capture the water dynamics in unsaturated and saturated zones. A Distributed Forest Wetland Hydrologic Model (DFWHM) was constructed and used to examine water dynamics in the different climates of three different watersheds (a cold region, a sub-tropic region, and a large-scale watershed.) A phenological index was used to represent the seasonal and species changes of the tree canopy while processes of snow packing, soil freezing, and snow and ice thawing were also included in the simulation. the cold region, the simulated fall of the groundwater level in winter due to soil freezing and rise in spring due to snow and ice melting compare well with the observed data.Because the evapotranspiration and interaction of surface water and groundwater are included in the model, the modeled seasonal trend of the groundwater level in the sub-tropic region is in agreement with observations.The comparison between modeled and observed hydrographs that the simulations in the large-scale watershed managed to capture the water dynamics in unsaturated and saturat ed zones.