Relationships between needle nutrient composition in Scots pine and Norway spruce stands and the respective concentrations in the organic layer and in percolation water

We explored how N, S, P, Ca, K, Mg, Zn and Mn concentrations in percolation water (PW) and organic layer (OL) are reflected in the respective element concentrations in Scots pine and Norway spruce current needles. For both tree species, N and Ca had the highest covariation (R adj 2 ≥ 0.73) between nutrient concentrations in the OL and in the needles. Mean N, S, P, K, Zn and Mn concentrations in PW significantly explained the variation in the respective needle concentrations on the spruce plots, and of K, Zn, and Mn in PW on the pine plots. The annual variation in needle element concentrations did not account for the respective variation in PW. Our results suggest that plant metabolism regulates the nutrient concentrations in the current needles more strongly in pine than in spruce, whereas the supply of soil nutrients is more clearly reflected in the nutrient concentrations of spruce.