Issue: July 12, 2008
Are roots of cut trees a landscape problem?
My husband recently cut down a tree that was about 50 feet high. I do not know what kind, but it was healthy and the reason he cut it was that its roots were coming up around our paving stones and were under all sorts of items. In other words, the roots were in the top two feet most of the time, they were not growing straight down. Now that the tree has been cut down and the stump has been somewhat removed, will the remaining gazillion roots eventually die or do we need to remove them also?
Since you do not know what kind of tree your husband cut, I will answer in a general manner. Some trees will sprout from the remaining trunk and roots once the tree has been cut. Other trees will not produce sprouts from their roots. In either case, it is not necessary to dig up the roots. If sprouts do form, you should remove them as soon as you see them. You can remove them physically by digging or cutting them at the ground level, or you can use an appropriate herbicide. To determine the appropriate herbicide, take a sample of the tree (if any remains now) or of the sprouts to your local NMSU Cooperative Extension Service office or a local nursery to have the plant identified. Once the tree has been identified (at least in a general sense) you can purchase the appropriate herbicide. If you choose chemical control, be sure to use the product exactly as recommended on the label (proper dilution, timing, and safety precautions). If you choose to just dig or cut the sprouts, you can be equally successful in eliminating the tree.
As the sprouts begin growing, they are drawing upon stored food reserves in the roots. By cutting the sprouts (or applying herbicide repeatedly) soon after sprouts appear, you can prevent them from storing more food in the roots. As they sprout again and draw again on the stored food, they will deplete the food reserves to an extent that prevents the roots from producing new sprouts. Once that has happened, the roots will begin to decay.
If your tree was the kind that does not sprout from the roots, you will not need to deal with the problem. Once your tree was cut, the problem was removed. You may notice some sinking of the soil around the tree over time as the roots decay and the soil collapses over the decayed roots.
By the way, you made a very important observation in your question. You observed that the roots were near the surface and not growing straight down. That is a correct description of how tree roots grow. There may be some roots (tap root, heart roots, and sinker roots) that grow down, but the majority of the roots of the tree are within two to three feet of the surface. This is an important point to understand when planting and caring for trees.
Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: email@example.com, office: 505-865-7340, ext. 113.
Please copy your County Extension Agent and indicate your county of residence when you submit your question!