Impact of road salting on Scots pine (Pinus sylvestris) and Norway spruce (Picea abies)

Evaluation of the impact of transport on the surrounding environment requires an ecosystem approach: to analyze components that provide information about the distribution of concentrations of the monitored contaminants and to allow an estimate of the dynamics of movement of these substances in the environment. Trees are used for biomonitoring for wide range of contaminants, coming not only from air pollution from industry or transport but also from winter chemical road maintenance. The research paper presents the determination of sodium and chloride ions content in assimilative organs of conifers and evaluates the influence of the contamination potential on these ions contents in needles of the Scots pine (Pinus sylvestris) and Norway spruce (Picea abies). Scots pine is studied a useful bioindicator for different tip of trace elements, but in the case of influence of winter maintenance, there is not so deep focusing as in the case of spruce. We have used this species of conifers for their usual occurrence. To assess the differences between sensitivity of salinity of different type of needles, the results of analysis of first- and second-year needles of Scots pine needles and samples of the Norway spruce were compared. The study was conducted in two different areas (for Scots pine and Norway spruce) in the Czech Republic. Samples of soils were collected near each tree of interest. The results of ions concentrations (Na, Cl) were evaluated depending on two factors: the distance from the road and the age of the needles. For evaluation of the impact of transport on the surrounding environment also the concentrations of wide range of elements were measured. The study confirmed a higher sensitivity of Norway spruce to salinity than in Scots pine. Given the confirmed increased sensitivity of spruce stands to the effects of winter road maintenance, spruce is not an appropriate tree species for the immediate vicinity of road infrastructure. Increased NaCl accumulation in the assimilation organs of the conifer trees near the road was confirmed and scales with concentrations were established to assess the degree of contamination.