Allocation of elements in a chronosequence of silver birch afforested on former agricultural lands

Research on the effect of birch regeneration on changes occurring in the environment on former farmlands included a quantitative and qualitative analysis of the biomass growing on the research plots. Five experimental plots were selected in the Mazovia region: two in Dobieszyn and the Kampinos National Park and one in Kozienice. The analysis performed on each plot was concerned with the amount and chemical composition of biomass in four patches of vegetation, characterised by the different ages of the birch trees growing there. The vegetation patches were classified according to age group, i.e. I: 1-4 years old, II: 5-8 years old, III: 9-12 years old and IV: over 12 years old. Biomass samples were collected in the field and determined in kg DM/ha using the following components: roots, stem, bark, branches, assimilation apparatus, litterfall and the total biomass of the other (except birch) plants. For all the above-mentioned groups, the content of the elements N, C, S, Ca, K, Mg, Na, P, Mn, Cu, Fe, Zn, Pb, and Cd was determined. This allowed us to obtain both the values of the concentrations of particular substances and their allocation in both the organic matter and litterfall. The aim of the research was to discover whether the allocation of elements changes with the age of birch growing on former farmland.