Girdling Roots
Certain trees chronically experience problematic girdling roots and can be prone to girdling root syndrome. Topping the list are maples, expecially Norway, American beech, poplars and the small-leaf linden cultivar "Greenspire".
Only those girdling roots that occur at the root collar area or above are problematic and considered chronically dangerous. Girdling roots that occur below the root collar area are not normally a threat to the trees' healthy or stability. If a tree has girdling roots, it is more likely to have problems than if it does not have a girdling root.
Any tree can develop root systems that could eventually result in girdling depending on how it was grown or planted. Root-bound plants often develop girdling roots if the roots are not pruned at planting time. Girdling roots can develop from poor planting techniques such as "twirling" a bare-root system into a planting hole that is too small for the roots, planting too deep, and planting in inadequate soil volumes.
Symptoms:
*Scorch, early fall coloration, early leaf drop, localized damage symptoms.
*Excessive twig dieback.
*Thin appearance to crown, overall stunt.
*Little to no step taper at ground level, or a flat side to the trunk.
*Leaning
*Vulnerability to other problems and environmental extremes.
Damage:
*Restriction of photosynthates to the root system.
*Root death.
*Loss of anchorage system.
*Creation of weak points in the stem at or above the root collar flare.