The effects of highly and moderately acid soils on total biomass, biomass partitioning, fine root characteristics and nutritional status of beech seedlings (Fagus sylvatica L.) were studied in a growth chamber experiment. In Haplic Arenosols seedlings grew slowly but equally well without damage symptoms in a highly acid and a moderately acid soil horizon. The moderately acid A(h) + B(w)-horizon of a Eutric Cambisol was favourable to seedling growth. The fine root development was reduced in the highly acid A + B(w)-horizon of a Dystric Cambisol and in the A(h) + E-horizon of a Haplic Podzol, the latter of which also caused increased mortality. Seedling growth in the B2-horizon of the Haplic Podzol was vigorous, in spite of a higher level of extractable Al and lower base saturation as compared with the A(h) + E-horizon. These results are interpreted in relation to soil acidity, soil Al and nutritional status of the seedlings. We conclude that neither Al-toxicity nor nutrient deficiency cause the damage symptoms observed in the A(h) + E-horizon of a Haplic Podzol and the fine root reduction in the A + B(w)-horizon of a Dystric Cambisol. The damage symptoms of the PZh(A) treatment seems to be more the result of H-toxicity or H-related factors other than nutrient shortage or Al-toxicity. Other pH-related toxic factors are discussed.
