Fig. 4

Bio-available (ammonium acetate, pH = 4.56) nutrient’s content in the soil organic horizons in forests dominated by spruce and pine within the Cajander’s forest site type 6, Lapland reserve, Murmansk region. S1 – spruce trunk (n = 5), S2 – middle of spruce crown (n = 5), S3 – edge of spruce crown (n = 5), S4 – between the spruce crowns (n = 5), P1 – pine trunk (n = 5), P2 – middle of pine crown (n = 5), P3 – edge of pine crown (n = 5), P4 – between the pine crowns (n = 5). Significance of differences between: S1 – P1: N (p = 0.05), Ca (p = 0.01), Mg (p = 0.004), K (p = 0.002), C/N (p = 0.02). S2 – P2: K (p = 0.01), C/N (p = 0.001); S3 – P3: N (p = 0.08), Mg (p = 0.07), K (p = 0.02). S4 – P4: C/N (p = 0.007); S1 – S2: C/N (p = 0.004). S1 – S4: N (p = 0.06), Ca (p = 0.008), Mg (p = 0.003), K (p = 0.0009). S2 – S3: C/N (p = 0.05); S2 – S4: Ca (p = 0.07), Mg (p = 0.05), K (p = 0.003), C/N (p = 1.47 × 10^− 5). S3 – S4: N (p = 0.02), Ca (p = 0.07), Mg (p = 0.03), K (p = 0.005). P2 – P4: N (p = 0.03), Ca (p = 0.04)