Squirrel Damage to Tree Bark

I had an interesting call from one of my clients in Grand Blanc last fall. She said, “I would like to know if you can tell me what happened to the bark on my Japanese maple. Yesterday it was fine, but today the bark on a couple of the branches is completely gone.” Due to the unusual nature of this statement, I made sure to get out there right away. What I discovered was something that is not commonly found on ornamental trees in a landscape setting – squirrel damage.

Squirrels, while often adorable and fun to watch, can sometimes cause significant damage to trees, through gnawing on the bark. Gnawing is a common behavior in both tree squirrels and ground squirrels because their front teeth never stop growing. So, they tend to chew on the bark for several reasons, from making nesting material to searching for food to wearing down their teeth. However, the damage they cause can leave trees vulnerable to disease, pests, and even structural failure.

Squirrels typically damage the bark during colder months, as they look for a way to access the cambium layer beneath the bark. This layer contains carbohydrates and water, and by chewing it, squirrels can disrupt the tree’s ability to transport water and nutrients. In severe cases, this can lead to girdling, where a complete ring of bark is removed, effectively starving the tree above the damaged area. This may result in branch dieback or the eventual death of the tree if the gnawing occurs around the main trunk of the plant.

Another risk of squirrel damage is the introduction of pathogens. Open wounds caused by chewing are perfect entry points for fungi, bacteria, and insects, which can further weaken the tree. In some cases, squirrels may also damage young trees, inhibiting their growth or causing long-term health problems.

Damage is easier to see on smaller trees as damage typically occurs on the top of a branch which may not be easily seen from the ground on larger trees. Tree care workers can easily see damage when inspecting a tree aloft.

To prevent squirrel damage, consider installing tree protectors like plastic wraps or metal collars around the trunks of vulnerable trees. Some homeowners in Grand Blanc have also chosen to provide a different food source for the squirrels. Keeping your trees healthy through regular fertilization will help them withstand the occasional squirrel nibble.

For this tree, wound protection was applied followed by deep root fertilization with nutrients, soil stimulants, and root stimulants.