There are great benefits for using deicing salts on streets and sidewalks in winter. During the summer following, high salt use can cause problems in water and nutrient uptake for nearby trees.

A University of Minnesota publication entitled “Minimizing De-Icing Salt Injury to Trees” addresses the concerns for injury to trees and how to control the injury. Symptoms include a browning of the leaf margins in late summer. This year I noticed a similar symptom on about 6 of the trees without sign of a pest. It was strange since rainfall had kept the trees moist. After reading this publication I knew exactly what was going on.

Salt injury to trees will come from two sources, roadway spray or sidewalk applications. The first source comes from salt applied to the street and car traffic will create a spray that can travel many feet out from the curb. This can be commonly seen if you park on any street and see the amazing amount of dirt collected even after a short time.
The second and highest concern is the use of de-icing salts on the sidewalks. Boulevards with trees can act as a drain for melting snow and spring rains. The salt increases the soil pH or soil chemistry that limits the tree from absorbing of water and essential nutrients in the soil.

There are several trees that are sensitive to these conditions and thus the symptoms and so I feel we have caught it before it becomes a serious lost of trees. I would ask homeowners and businesses to use de-icing salts sparingly on sidewalks especially near tree plantings. Use coarse sand instead and limit use to high-risk areas. Alternatives calcium chloride and calcium magnesium acetate (CMA) are safe to use around trees and plants. When shoveling and scrapping snow and ice avoid piling next or near the tree pits. In most cases the salt content is highly concentrated in these piles and melt-water will go directly to the tree roots.

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