The Case of the Sleeping Maple (girdling roots)

The case of the sleeping maple (girdling roots)

  Do you have a maple tree that just doesn’t look very healthy? Or perhaps the tree looks ok, but has barely grown over the years, especially compared to other trees?  Most likely your tree is not sleeping, but could very well have a girdling root problem.  Maple trees are one of our most widely planted tree species in the Milwaukee area.  For many years, the Norway maple tree has been the most popular of all the maples.  This tree comes in different varieties such as Crimson King, Emerald Lustre, and Swedler maple.  All of these varieties have one thing in common, girdling roots.  Norway maples all are highly susceptible to this fatal underground root weakness.

  Girdling roots circle around the trunk of the tree, generally right below the soil surface.  As the trunk, and the circling root become larger over time, and grow together, pressure begins to build up, and the tree is no longer able to pull up enough water and nutrients to support the canopy of the tree.  The circling root strangles the tree.  The tree starts to decline.  The genetics of the Norway maple tree make them much more prone to girdling roots than just about any other species.

In the best case scenario, the tree just doesn’t grow very much.  The tree takes on a stunted growth appearance, and the problem may not be very noticeable.  Severe cases will be much worse and lead to tree death.  The early signs can be subtle.  Thinner canopy with less leaves each progressive year, smaller leaves, lighter color to the leaf, and then dead branches, usually starting at the top.  The problem will get worse each year.

  Girdling roots are the number one killer of Norway maple trees.  The problem is so widespread, that as an arborist, I see an example of it just about every day.  If you suspect your maple tree has girdling roots, the best place to look is where the trunk goes into the ground.  A properly planted maple tree with have a trunk that flares out at the bottom, it will be wider before it goes into the ground.  You will be able to see the main structural roots originate off the trunk before they go into the ground.   A maple tree that has girdling roots will look more like a telephone pole going into the ground.  It will go straight down into the ground without getting wider at the base.  Sometimes the trunk will not be a nice round circle and may have a flat spot, indicating a girdling root that did not allow the trunk to widen out.

  There can be hope for this serious problem of Norway maple trees.  The number one thing to do is to make sure that the tree is planted correctly, and at the proper depth.  The main structural roots coming out of the trunk should just be visible on the surface.  Inspect the root ball at planting time.  If roots are wrapping around the trunk, cut them or re-orientate them away from the trunk of the tree.

  If you tree has already been in the ground for a number of years, it still may be possible to remove the girdling roots by excavating away the soil at the base of the tree and removing the offending root.  Hoppe Tree Service can use a special tool called an air spade to non invasively blow the soil away from the trunk and then remove the root.

  Sometimes it is too late to help.  If the girdling root is too large, it may not be possible to remove.  It will be too traumatic to the tree and not worth the effort.  That is why it is important to catch the problem early while your tree still has a fighting chance.

August Hoppe

Certified Arborist WI-077A

 
 
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