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Maple Tree #851373

Asked September 27, 2023, 8:56 AM EDT

Hello, I am wondering if this crack in this Maple Tree is of any concern. If yes, anything I can wrap around this area, sort of like a bandaid to close it up?

Sherburne County Minnesota

Expert Response

Thanks for your question.

Cracks in the bark of maple trees are common and are often caused by a variety of factors including weather, pests, and diseases. In your picture, I see some vertical cracks in the bark. These should not be of any great concern. Such cracks appear in the bark of maple trees when there are rapid temperature fluctuations.

These fluctuations could occur on warm, sunny days in the winter when the bark warms up, causing the cells to expand in the bark and wood directly under the bark. Then if temperatures drop very quickly, the bark cools and contracts. The wood under the bark does not cool as quickly, causing the bark to split. Very hot weather such as we experienced this past summer (2023), can also lead to cracks appearing in the bark. See:

https://aplustree.com/why-does-my-tree-have-bark-cracks-and-what-should-i-do/

However, I suspect that you are mainly concerned about the elliptical wound. This could be due to a large vertical crack that developed a few years back and is now in the process of healing. Here are two thoughts of mine:

1). Look at this wound carefully and if necessary clean it with water using a soft cloth or brush. Look especially at the bark around the wound and remove any loose bark.

2). Doing any type of wrapping (“band-aid”) is not generally recommended as this can trap water under it this in turn can lead to fungal infection. Sometimes a tree wound sealant is used when the injury is new but even in such cases there are mixed opinions. For older wounds, such as this appears to be, no sealant is used. See:

https://www.gardeningknowhow.com/ornamental/trees/tgen/wound-dressing-on-trees.htm

https://extension.unh.edu/blog/2019/07/should-i-cover-large-pruning-wounds-tree-wound-dressing - :~:text=In reality, pruning paint may,wounds seal on their own.

https://www.purdue.edu/fnr/extension/tree-wounds-and-healing/

Bottom line: for the rest of this 2023, just monitor things. Especially watch the wound’s edges to see if enlargements occur. This would be a good sign that the tree is attempting to seal things up. In 2024, if things seem to turn for the worse in the sense that there is an enlargement of the wound and/or if fluid leaks from it, you may want to have a professional arborist make a visit and an assessment. See the following for information on these and related points:

https://extension.tennessee.edu/publications/Documents/SP683.pdf

https://extension.umn.edu/planting-and-growing-guides/how-hire-tree-care-professional

http://extension.msstate.edu/publications/tree-wounds-should-they-be-repaired

https://mortonarb.org/plant-and-protect/tree-plant-care/plant-care-resources/trunk-wounds-and-decay/

Good luck. Please get back to us if you are further questions

An Ask Extension Expert Replied September 27, 2023, 10:01 AM EDT

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