One of the most common causes of tree damage is the result of mowers and string trimmers. Too often, city trees are unintentionally killed by the improper use of these garden tools.
The damage string trimmers 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 mowers and string trimmers 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. Weed prevention can happen by properly mulching the ground around the base of the tree. If weeds need to be removed from the base of the tree, this can be done by hand or with small hand tools.