The effect of Scots pine, Norway spruce and silver birch on the chemical composition of stand throughfall and upper soil percolation water in northern Finland

The aim of this study was to determine the effect of pine (Pinus sylvestris), spruce (Picea abies) and birch (Betula pendula) on the chemical composition of stand throughfall (TF), percolation water (PW) and forest soil in northern Finland. The order of the tree species as regards the pH was approximately the same in both the soil and PW samples: birch > spruce > pine (O horizon), birch > spruce = pine (E horizon). Tree species did not have a notable effect on the DOC concentrations in PW. The base saturation and the Ca and Mg concentrations were the highest in the birch stand. The total Al concentration in PW was mainly related to the concentration of organic Al complexes in all the stands. The total and organically complexed Al concentration was its smallest at a depth of 10 cm in the spruce stand. Whether the properties of DOC present under spruce are the reason for the smaller formation of organic Al complexes in the spruce stand requires further research.