Differences in soil properties in adjacent stands of Scots pine, Norway spruce and silver birch in SW Sweden

Soil properties were compared in adjacent 50-year-old Norway spruce, Scots pine and silver birch stands growing on similar soils in south-west Sweden. The effects of tree species were most apparent in the humus layer and decreased with soil depth. At 20–30 cm depth in the mineral soil, species differences in soil properties were small and mostly not significant. Soil C, N, K, Ca, Mg, and Na content, pH, base saturation and fine root biomass all significantly differed between humus layers of different species. Since the climate, parent material, land use history and soil type were similar, the differences can be ascribed to tree species. Spruce stands had the largest amounts of carbon stored down to 30 cm depth in mineral soil (7.3 kg C m−2), whereas birch stands, with the lowest production, smallest amount of litterfall and lowest C:N ratio in litter and humus, had the smallest carbon pool (4.1 kg C m−2), with pine intermediate (4.9 kg C m−2). Similarly, soil nitrogen pools amounted to 349, 269, and 240 g N m−2 for spruce, pine, and birch stands, respectively. The humus layer in birch stands was thin and mixed with mineral soil, and soil pH was highest in the birch stands. Spruce had the thickest humus layer with the lowest pH.

► On similar soils in Sweden, soil properties of birch, pine, and spruce differ.
► Less than one rotation period is enough for clear differences to emerge.
► More soil carbon is stored in spruce stands than in pine and birch stands.
► Birch stands have less available soil base cations than pine and spruce stands.
► Birch stands have higher pH and base saturation than pine and spruce stands.