EN
The study investigated the accuracy of thirty equations formulated in England, Sweden, Turkey, Lithuania and Spain and which aim to determine the aboveground biomass of black alder. The reference constituted of bark, timber, stem, branches and leaves dry biomass of 168 sample trees aged 6−96 from 56 alder stands located in the western part of Kotlina Sandomierska (south−eastern Poland). The analysed formulas, considering local conditions, resulted in biased biomass calculations. The evaluation of such components as leaves, branches, trunk timber or trunk bark is subject to systematic errors larger than a dozen or so per cent, and in certain ranges of breast height diameters − up to even a couple of dozens or a few hundred per cent. Only three out of 30 formulas may be considered useful for estimating aboveground biomass of black alder in Poland.