Replacing an oriental beech forest with a spruce plantation impacts nutrient concentrations in throughfall, stem flow, and O layer

To measure the nutrient leaching from canopy and the O layer in a natural oriental beech (Fagus orientalis Lipsky) forest and a Norway spruce (Picea abies) plantation. Materials and methods: From mid-July to early November, 2013, we measured throughfall (TF) (n=45), stemflow (SF) (n=12) and leaching from the O layer (n = 30) in a 0.5 ha sample plot in the Caspian region, Mazandaran province in northern Iran. Main results: Concentrations of PO43-, Na+, Mg2+, Ca2+ and K+ in the throughfall and the O layer in both beech and spruce forests significantly increased relative to gross rainfall. Concentrations of Ca2+ and Na+ in TF and SF were significantly higher in the spruce forest compared with the beech forest. Furthermore, in both forests, cumulative fluxes of all studied elements (with the exception of NH4+ and NO3-) during the study period were statistically different from those of GR (P<0.05). This study demonstrates that changing from a natural beech forest to a spruce plantation significantly alters nutrient fluxes exiting the canopy and the O layer. This information provides essential information on how planting exotic species will affect nutrient cycles in this region.