Fate of nitrogen compounds deposited to spruce (Picea abies Karst.) and pine (Pinus silvestris L.) forests located in different air pollution and climatic conditions

Measurements were made of NO3-N and NH4-N in bulk deposition, throughfall a nd soil solution on six permanent plots in pine and spruce stands located a long a transect from the south to the north of Poland. Location differed bo th in the level of air pollution level and in climatic parameters. The tota l N load calculated from throughfall ranged from 12.5 to 34 kg(-1)a(-1). Th e load of NH4-N exceeded the NO3-N contribution. Differences in total N loa d were not reflected in foliar N concentration. Present forest health statu s of stands determined by defoliation class, and do not appear to be relate d to their N deposition.