Are you noticing earlier than normal fall color or early leaf drop on any of your trees? Are any of these trees maples or lindens? If you answered yes to both of these questions, please keep reading. You may have stem girdling roots slowly killing your tree.
Urban landscapes are filled with trees that are planted too deeply. When root systems of trees are planted as little as six inches to several feet below the soil surface, they are buried too deep and unable to support the nutrient and water needs of the tree.
In effort to survive, trees often create new roots from trunk tissue at the soil surface. These roots are called epicormic roots.
Epicormic roots serve to keep the tree alive by acquiring nutrients and water. They do not provide structural stability for the tree and are prone to bending, often growing in a circling pattern. If the roots grow close enough to the tree trunk they will compress the sapwood and eventually cut off the flow of water and nutrients.
This disorder is called Stem Girdling Root Syndrome (SGR) and is one of the primary causes of tree decline in urban landscapes. Without treatment, Stem Girdling Root Syndrome will eventually prove fatal to the tree.
What to look for:
- No visible root flare at soil surface
- Tree trunk looks like a telephone pole going into the soil
- The trunk appears pinched at soil surface
- Tree canopy is thin or sparse
- Die-back in upper canopy
- Leaves are smaller than normal
- Leaves may be off-colored (yellow)
- Trees exhibit early fall color and leaf drop
- Trunk is flattened on one or more sides
- Sun scald or frost cracks visible on the trunk
- Wilting or scorching of leaves
What you can do about it:
Prevention is the best solution, but for trees already planted, early diagnosis of visible symptoms is essential for future tree health. Trees without a visible root flare at soil level are symptomatic of the disorder and are at risk to develop roots that may girdle the trunk. Diagnosis can also be based on tree species.
Professional arborists perform root excavations by using a special tool that uses high pressure air to blow debris and soil away from the base of a tree, exposing the root collar without damaging the tree roots. This evaluation determines the possibility of improving a tree’s condition.
If it is determined that problematic roots may be safely treated, surgical cuts are made to the roots that are girdling the tree and impacting trunk growth. It may be necessary to leave some offending roots, as only roots that do not affect tree stability and structure will be removed. There must also be enough roots left intact to provide sufficient nutrient and water uptake.
If tree trunk compression by girdling roots is too severe, removal of the tree may be the only option.