The research was carried out in the spruce forests of Barania Góra (Silesian Beskids, Poland) affected by pandemic dying of trees. Twenty-seven samples were collected from the O layer in two plots: 17 in a cut down forest infested with insect pests (bark beetle) and ten in a 120-year-old healthy forest. The analyses covered basic parameters (pH(H2O), pH(KCl), w(org), C(tot), N(tot), CEC) and the concentrations of aluminium in the fractions leached with 0.1 M BaCl(2) (Al(exch)), 0.5 M CuCl(2) and 0.1 M Na(4)P(2)O(7) (Al(bio)) solutions. The total aluminium concentration in the soil was assayed digesting samples with hydrofluoric acid. The effect of pH and organic matter content on the amount of exchangeable (Al(exch)) and bioavailable (Al(exch)) aluminium in the soil was analysed. It has been found that the soils in both plots are strongly acidic and contain 550 to 1,700 mg kg(-1) of exchangeable aluminium and 1,200 to 4,800 mg kg(-1) of bioavailable aluminium. The lack of disease symptoms in the spruce trees in plot 2 can be explained by the higher content of organic matter in the soil. Unfortunately, one might expect that the high concentration of exchangeable aluminium will also cause the trees in the area to wither.