Short-term impact of fertilization on ground vegetation in deciduous forest stands and tree plantation

This study examines the impact of fertilization with wood ash and ammonium nitrate on ground vegetation in Silver birch stands representing 4 forest types (Hylocomiosa, Myrtilloso-sphagnosa, Myrtillosa mel. and Myrtillosa turf. mel.), as well as in a deciduous tree (Alnus glutinosa, Betula pendula, Cerasus avium) plantation. Ground vegetation was assessed 2 years after application of fertilizers. The mean ground cover of individual species in moss, herb and shrub layer was determined. Species composition, species richness and species diversity were compared between fertilized and unfertilized plots. Shannon diversity index (H) was chosen as an indicator of species diversity. Results show that in Silver birch stands species composition in both control and fertilized plots is typical of the respective forest types. In the Ķeipene plantation, occurrence or increased abundance of several nitrophilous species was observed in the fertilized parcels. Statistically significant differences between H values of control and fertilized plots have been found only in the Myrtillosa mel. forest stand in the moss layer, as well as in the herb layer of one of the Hylocomiosa stands and Sweet cherry parcel in Ķeipene plantation. Long-term observations are required in order to determine if the observed differences in ground vegetation between control and fertilized areas persist longer.