Your Tree Will Thank You

Written by: Ron Gumz, Board Certified Master Arborist MN-0324B

Posted: 2019 | Plant Health Care | Root Collar Excavation | Summer | Tree and Shrub Care

At times, things you cannot see can be a problem. Certainly, tree root issues fall into this category. Stem girdling roots (SGR’s) and circling roots are not always visible and are a type of root issue that can cause big troubles for a tree.

Stem girdling roots are roots that have been misdirected and grow around or across the tree trunk hidden under the ground. Left unchecked, these roots will start causing problems for trees that watering, fertilization, treatments, and pruning cannot correct.

Some symptoms of girdling roots include:

• Lack of or no visible root flare present where the trunk enters the ground (like a telephone pole)
• Reduced or slow tree growth
• Stress leading to secondary items like insect or disease issues
• Thinning of or lack of leaves in the crown
• Trunk splitting or cracking
• Deformation of the natural shape of the crown

Symptoms usually start showing up just as a tree becomes a contributing plant in the landscape. It can take years for the roots and tree to grow large enough to cause conflicts. As the tree and its roots grow in diameter, the SGR’s act as a noose restricting 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. Maples and lindens are more often prone to this problem. The key is early intervention to help the tree survive if SGR’s are becoming a problem. Performing a root collar exam around the base of the tree trunk with an air spade may be recommended. An air spade uses compressed air to move excess soil and mulch away from the trunk of the tree. The goal for this process is to expose the root collar and/or the problematic roots around the root collar.

During a root collar exam, pruning out problematic roots may become possible. The amount of roots taken out varies from tree to tree depending on what is uncovered. As with any treatment to a living organism there are risks that must be weighed in this decision. After the exam, the area around the trunk should remain exposed so reoccurrence is less likely.

Prevention of SGR’s is important:

• Proper planting depth is critical to the tree’s long-term survivability! A newly planted tree’s root collar should be planted at or slightly above the soil level
• Keep mulch and soil away from the trunk. Avoid mulch volcanoes
• Perform root collar exams on trees in the landscape as recommended, especially when the root flare is not visible as site conditions around a tree may change over the life of a tree
• Maintain trees for growth and vigor

If you suspect that your tree or trees may be affected by stem girdling roots, please reach out to your local Wachtel Tree Science Certified Arborist. Your tree will thank you!