In our thesis, we investigated the influence of heavy metals on the growth of three tree species: beech (Fagus sylvatica L.), sycamore maple (Acer pseudoplatanus L.) and spruce (Picea abies (L.) H.Karst.). Soils contaminated with heavy metals were obtained from three locations: Žerjav pri Mežici, Prevalje and Podklošter (Arnoldstein, Austria). The soils among the locations in terms of soil type, parent material and land use (forest and agricultural soils). Half of each soil sample was previously remediated by a washing process using the chelating ligand EDTA, which is intended to remove heavy metals from soil. Seedlings of the selected species were grown in remediated and non remediated soils in a pot experiment. At the beginning of the experiment, heavy metals concentrations was determined in the soil before and after remediation. The pot experiment lasted for four growing seasons, each season seedling height was measured and the growth (high increment) was statistically evaluated at the end. In remediated soils, better growth of tree seedlings was shown, but survival rate was lower, while in non-remediated soils, on the contrary, lower growth and higher survival rate of seedlings were shown. Growth differences were also visible between species, sycamore maple had the highest growth in remediated soils, and spruce the lowest. Analysis of heavy metals in the soil showed that the contents of Cd, Pb and Zn in the remediated soil were lower than in the remediated soil. Analysis of leaves and needles showed differences in the content of heavy metals between seedlings grown in remediated and non-remediated soil. We conclude that soil remediation by the soil washing process using a chelating ligand is a process that reduces the amount of heavy metals in the soil and reduces their uptake into the leaves of seedlings and improves their height growth, but does not improve their survival rate.
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