Abstract:The dynamic of fine root biomass in mineral soil up to 45cm and their chemical composition were investigated in a 25 years old grand fir stand on a pseudogley soil from the waterlogged period to the vegetation period (November 1987-September 1988) . Under waterlogging the fine roots had considerably higher dead mass (5558 kg DS/ha) than living mass(3594 kg DS/ha). At the start of the vegetation period the total mass of the living fine roots increased by 50% and the total mass of the dead fine roots decrea...