Root Girdling

Root Girdling: Diagnosis and Treatment for Strangling Roots

If your tree has been slowly declining — thinning crown, early leaf drop, a flat-sided trunk with no visible root flare — girdling roots may be the cause. Root girdling is one of the most underdiagnosed causes of tree decline in urban and suburban landscapes, and one of the most preventable when caught early. Tree Care Enterprises has been diagnosing and correcting girdling root issues throughout the Rockford area since 1978.

What Is Root Girdling?

Girdling roots form when a tree's roots begin to grow in circles around the trunk or main lateral roots instead of spreading outward. Over time, these circling roots press against the stem, compressing the vascular tissue (phloem) just below the bark. As compression worsens, water and nutrient transport between the roots and canopy is progressively restricted — starving the tree from the inside out.

Girdling roots typically develop early in a tree's life, often as a result of being grown too long in a container (pot-bound roots that continue circling after transplant) or planted in a hole with smooth vertical walls where roots deflected rather than spread. The problem may not become visible for 10–20 years after planting, often appearing just when the tree has become a significant landscape feature.

Trees Most Commonly Affected in Northern Illinois

In the Rockford area, the most frequently affected species include red and Norway maples (among the most girdling-prone trees in the region), silver maple and box elder, linden (basswood), white pine, and ornamental crabapple and cherry. Any tree that spent time growing in a container before transplanting is at elevated risk.

Signs Your Tree May Have Girdling Roots

• No visible root flare at the base of the trunk — the trunk appears to go straight into the ground like a post
• A flat or compressed area on one side of the lower trunk
• Crown thinning, particularly on one side of the canopy
• Early fall color or premature leaf drop on one or more scaffold branches
• Bark ridges, swelling, or visible roots crossing the trunk at ground level
• Gradual decline over multiple growing seasons despite adequate water, with no obvious pest or disease explanation

Treatment: Air Spade Excavation and Surgical Root Removal

The most effective treatment for girdling roots is root collar excavation followed by surgical removal of the offending root. Our arborists use an air spade — a supersonic air tool that blasts compressed air to remove soil from around the root zone without cutting or damaging fine feeder roots. Once the root collar is exposed and the girdling root is mapped, the circling root is carefully severed and removed.

Not every girdling root should be cut. Roots that have grown deeply embedded into the trunk, or that represent a significant portion of the tree's structural root system, require more careful assessment. Our ISA Certified Arborists — John Richards (IL-0027A), Doug Edwards (IL-0505A), Matt Richards (IL-9831A), Jeremy Montana (IL-4690A), and Pete Montana (IL-4689A) — determine the best approach based on species, root size, depth of embedding, and overall tree health before any cutting begins.

Can a Girdled Tree Be Saved?

The prognosis depends largely on how long the girdling root has been present and how much of the vascular system has been compromised. Trees identified early — before canopy decline becomes severe — typically respond well to root collar excavation and surgical correction. Trees with significant trunk flaring loss or advanced crown dieback may have more limited outcomes, but early intervention can extend functional life and reduce hazard risk considerably.

Tree Care Enterprises holds TCIA accreditation and has been treating girdling root issues throughout the Rockford area and Lake Geneva region since 1978. If your tree shows any of the warning signs above, call 815-965-5757 to schedule a free evaluation. Early treatment gives your tree the best chance of full recovery.