Power line trimmers or weed eaters have become one of the most popular gardening tools. Almost everyone has one. Whether powered by electricity or gas, they quickly trim and edge lawns, and cut grass and weeds in areas which are difficult to reach with mowers. They create a neat, tidy look which is very appealing.
One of their common uses is to trim grass and weeds growing around trees. An occasional use around a well established tree probably does little damage. However, weekly use around trees, especially young ones, is devastating. Every time the line hits the bark of a tree, a little outer bark is removed. As fast as line trimmers rotate, that may be a hundred times in one trimming. After 20 or 30 trimmings, there may be little or no bark left.
The inner bark of a tree contains the tubes which carry food manufactured by the leaves down to the roots. If some of these tubes are damaged, less food reaches the roots. Slowing root growth means the tree can support fewer leaves. This reduces the growth rate and can actually reduce tree size as leaves are shed to balance top growth with root capacity. Once all the conducting tubes are cut, no more food reaches the roots and they begin to die. A slow, painful death of the leaves and branches follows.
The simplest way to avoid tree damage is to create a circle of mulched soil around the base of every tree which is free from grass and weeds. This should be a minimum 3 foot diameter circle for individual trees. The size of the circle should be increased with tree growth. Groups of trees and shrubs can have irregularly shaped beds around them.