Sycamore Maple (Acer pseudoplatanus L.) belongs to the typical pioneer trees found in contaminated ecosvstems where it can contribute to the phytostabilisation of heavy metals (HM) in soils. In this study, foliage reactions caused by the experimental exposure to copper/zinc/cadmium lead = 640/3000/10/90 mg/kg were investigated in trees following development of distinct visible symptoms of stress in crown foliage during the third year of exposure. Low amounts of HM were translocated to the foliage and no reduction of foliage biomass was recorded. Only zinc reached concentrations near the toxicity level, especially in older foliage, and its involvement in stress reactions was confirmed by the morphology of visible symptoms, cytochemical micro-localisation and structural changes in the leaves. Low quantities of zinc reached sensitive sites in the leaf blade and triggered oxidative stress. Phytoremediation potential of Sycamore Maple includes both a phytostabilisation and bioindication component. The latter can be useful for monitoring and surveillance purposes.