Influence of road salting on the adjacent Norway spruce (Picea abies) forest

Winter deicing and traffic spreads salt to road-adjacent Norway spruce trees in the form of spraying and salt slops. Our use of (NaCl)-Cl-36 revealed roots as the main pathway of salt uptake. One-shot application of a concentrated (NaCl)-Cl-36 solution to spruce saplings by both irrigation and spraying causes macroscopic damage to the needles and affects the needle phyllosphere. Irrigation affects the trees more than spraying because Cl- uptake through roots is faster and eventually leads to higher chloride content in the plant. Along with the root-needle route, spray-deposited chloride from the needles is re-transported back into the soil and again taken up by roots to needles.