The process-oriented model PnET-N-DNDC describing biogeochemical cycling of C- and N and N-trace gas fluxes (N₂O and NO) in forest ecosystems was tested for its sensitivity to changes in environmental factors (e.g., temperature, precipitation, solar radiation, atmospheric N-deposition, soil characteristics). Sensitivity analyses revealed that predicted N-cycling and N-trace gas emissions varied within measured ranges. For model validation, data sets of N-trace gas emissions from seven different temperate forest ecosystems in the United States, Denmark, Austria, and Germany were used. Simulations of N₂O emissions revealed that field observations and model predictions agreed well for both flux magnitude and its seasonal pattern. Differences between predicted and measured mean N₂O fluxes were <27%. An exception to this was the N-limited pine stand at Harvard Forest, where predictions of fluxes deviated by 380% from field measurements. This difference is most likely due to a missing mechanism in PnET-N-DNDC describing uptake of atmospheric N₂O by soils. PnET-N-DNDC was also validated for its capability to predict NO emission from soils. Predicted and measured mean NO fluxes at three different field sites agreed within a range of ±13%. The correlation between modeled and predicted NO emissions from the spruce and beech stand at the Höglwald Forest was r ² = 0.24 (spruce) and r ² = 0.35 (beech), respectively. The results obtained from both sensitivity analyses and validations with field data sets from temperate forest soils indicate that PnET-N-DNDC can be successfully used to predict N₂O and NO emissions from a broad range of temperate forest sites.