Damaged bark on yellow-wood tree

(Question)

-Yellow-wood tree planted (by the City) in October 2020 is about 8-9 feet tall. It’s in a very sunny spot (south and west exposure). The soil is sandy.
-Today I removed the protective guard around the bottom of the trunk and saw that the bottom 2 or so inches of the trunk doesn’t have any bark (see photo).
-Though the most of the guard is loose and barely touches the trunk, it does curve in at the bottom and contact the trunk there, though not very tightly.
-The tree, though not seriously declining, doesn’t seem to be thriving – the leaves are yellowing in places and have brown spots. This has been happening for about a month, gradually getting worse.
-It’s watered once a week slowly for 4-5 hours. It has mulch (wood chips) around it, which sometimes end up by the trunk, but only in a thin layer. I’ve also added compost a couple of times (shoveled away the mulch first, then put it back).
Questions:
-Is the lack of bark at the bottom of the trunk of concern?
-Should the bottom bare section of the trunk be covered up with soil, i.e. should the soil level be raised?
-Should the guard remain off the trunk or be reinstalled? Or should a different guard be used?
Thank you!

(Answer)

Thank you for contacting Toronto Master Gardeners.  The loss of tree bark  or tree girdling can seriously damage a tree.  It is not clear from your photograph whether the bark removed from the tree completely encircles the tree.  If it does, the tree has a good chance of dying.  What is termed the phloem layer of tissue under the bark carries the food synthesized by the leaves to the roots.  Having no bark at some point on the trunk of the tree interrupts this process which will cause the roots and ultimately the tree to die.  Since the city planted the tree a city staff will come to assess it and identify what needs to be done.  As soon as possible call the city at 311, explain the situation and a service request will be processed.  Click here for more information on repairing bark damage on trees. Good luck with your yellow-wood tree.

September 5, 2021