Short-term effects of alternative de-icing chemicals on tree sapling performance

The use of sodium chloride (NaCl) as a road de-icer causes environmental problems and alternatives with less environmental impact are sought. This study compares the effects of three de-icers, calcium magnesium acetate (CMA), potassium formate (KFo) and NaCl, on tree performance. Growth and stress responses of tree saplings were tested in a pot experiment with five species and three substrates at increasing de-icer concentrations in soil during vegetative growth. A negative effect of increasing soil concentrations of de-icers were found for many of the responses, but the effects varied among plant species. Root growth decreased in both of two species tested, leaf biomass decreased in four of the five species and stem diameter increase decreased in two of the five species. De-icer treatments had no effect on specific leaf area, relative chlorophyll content, height increase or chlorophyll fluorescence (Fv/Fm) responses. The negative effects of increasing de-icer concentration were independent of substrate characteristics, except for root growth in Acer platanoides and Pinus sylvestris and shoot growth in A. platanoides, where higher soil organic matter content improved plant performance under salinity. The negative effects of increasing concentrations were similar for all three de-icers when compared on a similar anion basis. Hence, the two organic de-icers, CMA and KFo, did not have less impact on tree sapling performance than NaCl during active growth.