Salt can kill trees. Salt is sometimes used to kill tree stumps. If soil has been contaminated with salt, it cannot support any plant life.
If soil has salt in it, the salt separates into sodium and chloride ions. Chloride ions can be absorbed by the roots in the early spring. The chloride can enter the sap and the shoots; this prevents the buds from opening. The sodium ions travel the same path as essential nutrients. The sodium ions can halt the tree's transport system. This prevents magnesium and potassium from being absorbed. As a result, the tree cannot make chlorophyll. A tree can die of thirst if it is exposed to enough salt.