Adaptation of short-lived plants to pollutants is a well documented phenomenon, but with long-lived trees pollution resistance has been found much less frequently. Mountain birch is a likely candidate for detecting resistance, as it is one of the few woody plants surviving in the heavily polluted industrial barrens of the Kola Peninsula, NW Russia. The current experiment was designed to find out whether 60 to 70 years of pollution impact from two nickel-copper smelters has caused selection of resistant birch genotypes and to investigate possible trade-offs between pollution resistance and competitive ability in clean conditions.
Seedlings from polluted sites outperformed seedlings from pristine sites in the heavy metal treatment, and vice versa, seedlings from pristine sites outperformed seedlings from polluted sites in the control treatment. I suggest that the superior performance of seedlings from polluted sites in the heavy metal treatment was a result of either heavy metal resistance or adaptive phenotypic plasticity, whereas the better performance of seedlings from pristine sites in the control treatment was a result of Greater competitive ability.