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Posts Tagged ‘girdling roots’

Last February I wrote about the bare-root transplant of a large Katsura tree (Cercidophyllum japonicum) at UMass, beautifully executed by the pros at Foti Landscape and Tree. Matt Foti just sent me a photo he took last week of the tree, which has settled into its new home nicely.

Though the crew kept a large slug of soil under the tree’s butt for the move, Matt told me that they did some excavation at the root flare, as they always do, to check for girdling, circling, or damaged roots. (I hadn’t noticed the excavation when I first saw the transplant photos, but if you click back to that post you’ll notice it.) The crew found a girdling root and removed it — and clearly, from this current photo, the tree didn’t skip a beat.

Even in a backlit shot on a very hot day this tree is looking happy.

Even in a backlit shot on a very hot day this tree is looking happy.

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Last year I worked on a large mall planting project.  A number of trees had to be pulled out to make way for a new parking layout; the islands they had been growing in were removed and paved over, with new islands located in a different configuration.  Most of the trees were hauled away by the landscape contractor, but one ended up in a discard pile next to the mountain of loam that had been excavated for reuse.

I was interested in the root configuration on this six-inch caliper red maple.  A mass of fibrous roots wrapped closely around the tree’s trunk, much like cotton-candy filaments spun around a paper cone.  Looking at it more closely, I found that the fibrous roots grew out of thicker woody roots, some of which had been cut during the tree’s original ball-and-burlapping, and some of which, growing since that operation, were circling the trunk.  Take a look:

Fibrous roots circling the six-inch red maple trunk.

Pulled away from the trunk, the roots clearly are circling it. Over time, as the tree grew in girth, these roots likely would have constricted the flow of nutrients between root mass and crown

This sort of circling root is usually seen when the soil mass in a B&B root ball is of different porosity from the soil surrounding it; moisture will not move from one soil mass to the other until one mass is completely saturated.  Because roots tend to grow where moisture and oxygen are available, they will often stay within the root ball, and circle around the trunk as they grow.  The problem is made worse when burlap is not pulled away from the ball, as the burlap constitutes yet another interface for the moisture to move through.

Here's the tree's underside. Note the girdling root snaking on top of the big torn root facing the camera, and the curiously self-contained look of this root mass. The tree's problems likely began early in its life.

Not every B&B tree has these problems, and in those that do, not every rooting problem can be remedied at planting time.  Judicious treatment — looking for circling roots that can become girdling roots, cutting back girdling roots and cutting or redirecting circling roots, roughing up the sides of the root ball, removing or cutting down wire baskets, pulling down or removing burlap — can go a long way in helping B&B trees establish better in the landscape, and in remedying problems that threaten a tree’s long-term health and viability.  For more discussion on root issues affecting B&B trees, check out this post on Matt Foti’s station at the MAA’s Elm Bank bare-root workshop in September 2009.

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I was shuffling through some photos today, hunting for an illustration of girdling roots, thinking that I’d use one of a myriad of pix I have of subgrade snarlups.  But this picture popped up, and it seemed useful to show how a root that seems insignificant in infancy can grow to have an adverse effect on the health of the tree from which it springs.

These two girdling roots started out as thin, wirelike strands growing past the trunk of a sapling.

These two girdling roots started out as thin, wirelike strands growing past the trunk of a sapling.

This tree is a Norway maple in our backyard  (yes, we still have a couple of them).  From its position in the lawn I’m betting that someone planted it.  At the time of planting, it would have been a small tree — perhaps a 5-foot sapling dug from the yard’s border and moved to the lawn, or maybe one of the 1.5″ caliper whips given away by our town one year.

If you envision the young transplant then, you’ll imagine those two girdling roots as a couple of very thin, quite insignificant-looking roots, running parallel to and about two feet away from the trunk of that skinny tree.  They might have been considered circling roots, they might simply have just gotten twisted the wrong way in planting and continued to grow straight past the trunk.

As the tree grew in height it also grew in girth; the crown branched out, the trunk got thicker.  As the trunk got thicker, the roots and branches thickened.  A harmless condition in the tree’s juvenile days has turned into a bit of a problem in its middle age.  Now the skinny roots have fattened up, and have begun to squeeze the vascular tissue in the roots runny radially out from the trunk.  Bark above the girdling roots is traumatized (and not just by the squirrels that run up and down every morning) by constriction.  There’s a bit of dieback in the crown this year — though that may have been caused by something else (winter breakage invaded by fungus? Norway maple cussedness?)

The solution?  Chiseling the girdling roots away from the constricted roots to free up that vascular system could help, though at this stage it would be interesting to see if that section of root and trunk flare could really recover.  I have been using the Norway maples in the yard — the two mature ones, and a small thicket of saplings — as a small laboratory, so will keep watching to see what happens here.  Feel free to comment below….

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At the MAA Elm Bank workshop on September 10, 2009, Matt Foti demonstrated how to address root problems at the time of planting.  He had a fairly large collection of trunk-and-root masses to illustrate his points, and used them to show how girdling roots, secondary root systems, and J-rooted systems can develop as a result of poor planting or growing practices.

Matt first showed a couple of forest saplings he had pulled early in the day to illustrate how a naturally-seeded tree’s roots grow.  The sapling’s roots were evenly spaced around its stem, and extended out a distance relatively equivalent to the distance its topgrowth extended from the stem.

This little forest-grown white pine has a clean, evenly spaced root system.

This little forest-grown white pine has a clean, evenly spaced root system.

He then pointed to a couple of nursery-grown trees whose rooting problems had become evident after several years.

These root systems have been cut in the digging process.  In an attempt to regrow roots, the foreground tree has sent out a secondary root system, several of which are beginning to girdle other roots.  Kept too long in a burlapped ball or in a container, roots will often turn back in to the ball, making effective planting and long-term growth problematic.

These root systems have been cut in the digging process. In an attempt to regrow roots, the foreground tree has sent out a secondary root system, several of which are beginning to girdle other roots. Kept too long in a burlapped ball or in a container, roots will often turn back in to the ball, making effective planting and long-term growth problematic.

Shrubs as well as trees are susceptible to root problems; Matt dismantled an Ilex verticillata root mass to illustrate how he treats roots bound in a container or in burlap before planting.

Fibrous roots hold together in a near solid mass right out of the container.

Fibrous roots hold together in a near solid mass right out of the container.

Using a three-pronged fork to untangle the root mass.  For a bigger shrub or small tree, a machete or pitchfork may work well to loosen soil and reorient roots.

Using a three-pronged fork to untangle the root mass. For a bigger shrub or small tree, a machete or pitchfork may work well to loosen soil and reorient roots.

Ilex verticillata root mass, now ready for planting.

Ilex verticillata root mass, now ready for planting.

Soil can present another problem for nursery-dug B&B trees.  Clay soils make sturdy root balls, which can be useful for shipping, but not so great for root growth.

This pair of trees have root masses encased in rock-hard clay soils.  Note the solid clumps of clay in the foreground, and root growth only on top of the root ball -- these roots found it impossible to grow into and through this soil.  Breaking up the soil in a root ball like this before planting promotes the tree's future health; leaving this kind of root ball intact almost guarantees tree stress and decline.

This pair of trees have root masses encased in rock-hard clay soils. Note the solid clumps of clay in the foreground, and root growth only on top of the root ball -- these roots found it impossible to grow into and through this soil. Breaking up the soil in a root ball like this before planting promotes the tree's future health; leaving this kind of root ball intact almost guarantees tree stress and decline.

Closeup of rock-hard clay root ball, broken apart (fairly violently) for demonstration purposes.

Closeup of rock-hard clay root ball, broken apart (fairly violently) for demonstration purposes.

Another example of a dense clay root ball that constricted root growth to the tree's great detriment.  Soil had also been piled up around this tree's trunk flare, further challenging its ability to live.  Tough conditions for a tree to grow in.

Another example of a dense clay root ball that constricted root growth to the tree's great detriment. Soil had also been piled up around this tree's trunk flare, further challenging its ability to live. Tough conditions for a tree to grow in...

The point of these illustrations was to show how necessary it is, when planting a tree or shrub, to work with the root ball before covering it with soil.  Removing wire baskets, removing burlap, loosening or removing the soil, untangling roots as best as possible, pruning roots when necessary — all these tactics make up a strategy for promoting real tree growth.  Bare-root techniques have shown that a great deal of the work that arborists do these days is remedial — that is, is work intended to remedy poor growing, digging, or planting practices.  With the knowledge arborists now have of how root issues so obviously affect plant health, it only makes sense to attend to those issues early on, to avoid greater problems later.

Demonstrating arborist at this station:

Matt Foti, Matthew R. Foti Landscape and Tree Service, Inc., Lexington, MA

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