Avoiding String-Trimmer Damage on Trees

String trimmers can seriously damage trees. Here's how to trim around your trees safely.

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Filed under: Trees, Lawn Care, Mulching, Plant Disease

Trees get damaged by all kinds of things, the most obvious of which includes weather — in the form of ice, snow and high winds — as well as pests and diseases. But, believe it or not, one of the most common causes of tree damage is the result of a string trimmer.

The damage these mechanical devices cause can be considerable. When a tree's trunk is damaged by a string trimmer, the open wound becomes an invasion site for pests and diseases. If the wound wraps all the way around the trunk, it may cut off the tree's vascular system. When that happens, the tree can't take up water and nutrients, and in no time it may die. So what's the solution?

The most obvious way to avoid the problem is to simply be careful and keep the string trimmer a safe distance away from the trunk of the tree. But that's not as easy as it sounds, especially with string trimmers that automatically feed more line as the line gets shorter. Another easy way to avoid damage is to plant the tree in a mulched bed so that the need for trimming close to the trunk is eliminated.

But when all else fails, you can use one of several different types of inexpensive tree guards, all of which essentially work the same way.

By wrapping one of the guards around the trunk of the tree, you protect the trunk from string trimmer damage.

As the tree grows, make sure to check on the tree guard to see if it needs to be expanded or replaced with a larger guard to fit the width of the trunk.