Will Salt Kill Small Trees?

Size

While salt can kill trees, the size of the tree is not the main consideration. Certain trees are more susceptible to salt damage than others, and young trees are more susceptible than mature ones. Because young trees are smaller than mature trees -- and have smaller root systems -- this may have given rise to the misconception that small trees die of salt injury. Shrubs and trees that tolerate salt include arborvitae, yew, lilac, staghorn sumac and many varieties of oak, pine, birch and cedar.

Salt spray from road salt put down in the winter can harm trees, as can excess salt that gets into the soil from fertilizers with high salt contents. Water high in salt can contaminate plants over time if the salts aren't leached out of the soil. Salty bodies of water, like estuaries, can damage trees if they flood their banks. Trees located as much as 50 feet from the salty spot can show damage.

Trees that are highly sensitive to salt damage, such as white pine, can generally tolerate one year's exposure to salt. A second year of high salt exposure can kill the trees. Trees that have greater resistance to salty conditions can display salt injury but are less likely to die. Symptoms of salt damage include white salt residue on plant leaves and death of leaves and twigs. This may be on only one side of the tree, if it receives salt via road spray, or on the whole tree.

If you fear salt will injure your young trees, protect them in winter by tying burlap around the exterior of the tree. If you notice salt on exposed tree leaves, douse them with water after the storm to dislodge some salt, and rinse them again in spring. Switching from salt to sand for personal de-icing helps limit the tree's exposure.