Girdling Roots: Why Lansing Maples Decline and Die Early

Published August 8, 2026 by Lansing Tree Services

Here is the pattern we get called out to every August. A maple in a Lansing front yard, twenty years old, planted by the builder. The homeowner says it has been thinning at the top for a few years and this summer half the crown looks bad. Nothing else in the yard is sick. No borer holes, no fungus, no storm damage. The tree is being strangled by its own root, and it has been happening quietly since the day it was planted.

Stem girdling roots do not look like anything until they look like everything. This guide covers what they are, why maples get them, how a bag of mulch turns into a slow-motion killing tool, what to check on your own trees this weekend, and what an arborist can and cannot fix once the damage is done.

What a Girdling Root Actually Does

Roots are supposed to run outward from the trunk, spreading like spokes. A girdling root instead wraps around the trunk, or across the base of it, and stays there. Both the root and the trunk keep adding wood every year, so the gap between them closes. Eventually the root is pressing hard into the trunk.

What gets crushed is the tissue just under the bark, and that tissue is the tree's plumbing. Water moves up through the sapwood, sugars move down from the leaves through the phloem, and a girdling root pinches both. The part of the crown fed by the constricted side gets less water. Sugars headed down to the roots pile up above the pinch instead of arriving. The tree does not die from an attack. It runs out of supply lines.

That is why the timeline is so long and so confusing to homeowners. Nothing happens for ten or fifteen years. Then the tree starts thinning on one side, leafs out later each spring, holds smaller leaves, and finally begins losing whole branches. By the time it is obvious, the root has been doing its work for most of the tree's life.

Why Maples Take the Worst of It

Maples are the species most frequently affected by stem girdling roots, and mid-Michigan planted a lot of them. Drive any 1970s or 1980s Lansing, East Lansing, or Okemos subdivision and you will pass hundreds of Norway and red maples set into small planting holes in heavy soil.

Three things stack up. Maples root shallowly and aggressively, so a root that meets resistance turns and follows the path of least resistance, which in a nursery container or a slick-sided planting hole means going in a circle. Maples also tolerate deep planting long enough for the problem to establish, unlike species that decline fast and get replaced early. And maples are the trees homeowners most want to keep, so they stay in the ground for decades while the root does its work.

Silver maple has its own separate set of structural problems in this region, which we cover in the silver maple guide. Girdling roots are the quieter issue that affects the whole genus.

The Mulch Volcano Problem

Every spring, mulch goes down in cones piled a foot high against tree trunks. It looks tidy. It is one of the most damaging things done to landscape trees in Michigan.

Two separate injuries come from it. First, bark that stays constantly moist starts to decay, and that decay lets pathogens into tissue that was designed to be dry and exposed. Second, and worse, a buried trunk grows roots. The tree responds to soil piled against its stem by sending out new roots from the buried bark, and those adventitious roots have nowhere to go but around. They wrap the flare and become the girdling roots that show up as decline fifteen years later.

MSU Extension's guidance is 3 to 4 inches of mulch, tapered to about an inch near the trunk, and never piled against it. Ohio State Extension has been running the same warning about mulch volcanoes for years, and the University of Maryland's "free the flare" campaign exists for exactly this reason. The correct shape is a wide flat ring with the root flare visible in the middle. If you cannot see where the trunk widens out at the bottom, there is too much material on it.

The fix is free and takes ten minutes. Pull the mulch back with your hands until the flare is exposed. If you hit roots wrapped around the trunk on the way down, you have found your answer.

What to Check on Your Own Trees

Go stand at the base of each significant tree in your yard and look for these.

Is there a visible root flare? A healthy trunk flares out where it meets the ground. If the trunk enters the soil like a post, the flare is buried or a root is crossing it. This is the single most useful thing a homeowner can check.

Is the trunk flat on one side? A trunk that is round everywhere except one flattened face, low down, is being pressed by something. That something is usually a root just below the surface.

Is the crown uneven? Thinning, small leaves, or early fall color on one side while the other side looks normal points to a supply problem on the affected side rather than a whole-tree issue like drought or disease. The broader checklist is in our guide to signs a tree is dying.

Is there mulch or soil against the bark? Grade changes from landscaping projects bury flares just as effectively as mulch does, and they are harder to spot because they look like the original grade.

Do this in late summer, which is now. Stress shows most clearly in August and September, after the tree has spent a full season trying to move water through a constriction.

What Can Still Be Done

It depends entirely on how far along it is, and that means excavating the flare to see what is actually there. Careful hand or air excavation around the base exposes the root system in the top few inches, which is where the problem lives.

If a single root is crossing the flare and it is small relative to the trunk, severing it is usually the right call. The tree loses a modest amount of root and gains back its plumbing. Trees caught at this stage often recover well.

If the root is large, if several roots are involved, or if the trunk has already grown around and over them, the decision gets harder. Cutting a major structural root can destabilize a tree, and removing a constriction that the tree has already compensated for does not always help. There are cases where the honest advice is to manage the tree's decline, keep deadwood out of the crown, and plan for eventual removal rather than pay for a repair that will not work.

Prevention is where the real money is. Plant so the root flare sits at or slightly above grade, cut and straighten circling roots at planting time, and keep mulch off the bark for the life of the tree. Those three habits eliminate almost all of this. For established trees, a look at the base during routine pruning work costs nothing extra and catches problems while they can still be solved.

Frequently Asked Questions

What is a stem girdling root?

It is a root that circles the trunk instead of growing out from it, and as both keep thickening the root presses into the trunk and chokes off the flow of water and sugars. The tree slowly starves the tissue above the constriction. The damage is mechanical, not a disease, and it can take fifteen years to show.

How do I tell if my tree has girdling roots?

Look at the base. A healthy trunk widens into a visible root flare where it meets the soil, like the bottom of a wine bottle. A tree with girdling roots often goes straight into the ground like a telephone pole, with no flare at all. One side of the crown thinning while the other looks fine is another common tell.

Why are maples affected more than other trees?

Maples are the species most often affected. They root aggressively and shallowly, they are planted heavily in Lansing and East Lansing neighborhoods, and they tolerate being set too deep long enough for the problem to develop out of sight. Norway maple in particular is well known for circling roots in landscape settings.

Is a mulch volcano really that bad?

Yes, and it is the most common self-inflicted tree problem in mid-Michigan yards. Mulch piled against the trunk keeps the bark constantly wet, which invites decay and lets pathogens in, and it encourages new roots to grow out of the buried trunk. Those adventitious roots are exactly the ones that end up girdling the flare.

How deep should mulch be around a tree?

MSU Extension puts adequate mulch depth at 3 to 4 inches, tapering down to about an inch near the trunk and never piled against it. Spread it out in a wide ring instead of up in a cone. The goal is a flat doughnut with the root flare exposed in the middle, not a volcano with the trunk buried in the crater.

Can girdling roots be fixed?

Sometimes. If the root is small relative to the trunk and the constriction is not yet severe, an arborist can excavate the flare and sever the offending root. If the root is large, or several are involved, or the trunk has already been deformed around them, cutting can destabilize the tree. The call depends on what excavation reveals.