This segment is on string trimmers and young trees. While talking to an extension agent he said he got a call from a property owner who said that all the trees along their property line had suddenly began to die. The property owner said the trees had been planted about three years and they had done fine until recently. Suddenly they took a turn for the worst and the leaves began to wilt and fall off in the middle of summer. The property owner wanted to know what disease they had to see if they could be saved.
Don't wack young trees
The extension agent visited the property and asked the property owner what had happened in the three years, to see if they had done anything different, because the trees didnĎt appear to be diseased. The property owner said they had done nothing different during the three years the trees were in. The agent inspected the trees and found no noticeable signs of disease. The agent continued to inspect the trunk, and below the grass line he found a well worn continuous line all the way around the young trees. The death of the trees was the result of the property owner trimming grass around the trees with a string trimmer and damaging the bark of the tree on a continuous basis. Eventually as the property owner continued to use the string trimmer around the tree it began to damage the internal layers of the tree that provide the food and water for the tree to survive.
When the water and food gets transferred up the tree it is stored in the cells of the tree
and used as needed. As the damage progressed it reached a point where the food and water supply for the tree was cut off by the damage, but the trees didnít die.
Instead, the trees began to use the energy stored in the cells and continued to produce leaves and appear perfectly healthy. This process can go on for a period of time depending on the ability of the tree to store energy and water. Usually what will tip the scale is when the tree becomes stressed by hot weather, or disease. When this occurs the stress takes a toll on the tree quickly, because the tree does not have the ability to provide additional water or energy and it begins to die.
Photos can be seen here at Girdled Walnut Trees. If you read the comments below the pictures you will see the tree produced leaves and nuts even though the food and water supply lines for the tree was cut off. That should give you an idea of how long it can take before the tree actually dies.
When you plant new trees you should take the time to protect the trees if you plan to use a string trimmer. You can do this by placing something around the tree to protect it so the string trimmer can not reach the bark. I have seen pieces of large white PVC pipe slit length wise about six inches high and placed around the tree, and I have seen people wrap the tree.
My preference would be to clear the grass from around the base of the tree and either keep it bare dirt or mulch the area around the trunk so grasses donít grow next to the base of the tree. Then you donít have to get the trimmer near the base of the tree.
Monty, Master Gardener