By: Ron Gumz, Certified Arborist MN-0324A
Sometimes things you cannot see can be a problem. Certainly this is the case with most root problems of trees. Stem girdling roots are one type of root issue that can cause big troubles for a tree without ever being seen.
Stem girdling roots (SGR’s) are roots that have been misdirected and grow around or across the trunk of the tree. Left unchecked, these roots will start causing problems for trees that watering, fertilization and pruning cannot correct. Some early symptoms of girdling roots include:
-Reduced or slowed growth
-Deformation of the natural shape of the crown
-Lack of or no visible root flare present where the trunk enters the ground (like a telephone pole)
-Thinning of or lack of leaves in the crown
-Trunk splitting or cracking
These symptoms start showing up just as the tree is getting large enough to become an important part of the landscape. The reason for this delay is because it takes some time for the roots and the tree to grow large enough to cause the conflict. As the roots grow and the tree grows, the SGR’s act as a noose restricting the movement of water, nutrients and food within the tree which can lead to the death of the tree.
Any type of tree can be susceptible to SGR’s. Certain types of trees like maples and lindens are more prone to this problem than others.
Early intervention is key to helping the tree survive, if SGR’s are becoming a problem. Performing a root collar exam with an air spade may be recommended. An air spade, which is based on a compressed air system, is used to move the soil away from the trunk of the tree so the problematic roots and the root collar may be examined.
Once the area around the trunk is exposed, the offending roots can be pruned out if possible. After the exam, the area around the trunk should remain exposed so reoccurrence is less likely. Prevention of SGR’s is important. Keep mulch and soil away from the trunk of the tree to avoid girdling roots. Avoid mulch volcanoes! A proper tree evaluation cannot be done without being able to assess the root collar.
If tree roots do not have soil around the trunk of the tree to grow into, they will not create a problem. The root tips will dry out if not protected by the moist soil and will self prune when exposed to the air. This is why planting depth is absolutely critical to the tree’s long-term survivability! Planting too deep may rank up there with improper pruning as two of the most crippling procedures done to trees.
Another preventive measure to avoid girdling roots is to perform a root collar exam as a preventive measure on any tree that has been in the landscape for approximately 5 to 10 years. This will check for excessive soil buildup around the trunk and enable removal of roots before they create problems when the tree is larger. This preventive measure is very similar to going to the dentist to have your teeth cleaned and examined to avoid bigger problems in the future.
So the next time you look at your tree, ask yourself “Do I see a good root flare? Or does it look more like the base of a telephone pole?” If you suspect a problem, get in touch with your Wachtel Certified Arborist.