A hemlock tree, left, with close to 30% of its branches clipped off, presumably by a porcupine; center, the larger teeth marks indicative of porcupine damage; right, bark chewed off a boxelder by squirrels, almost from top to bottom.
After a couple of unusual reports of squirrels chewing the bark and buds of maple trees, I reached out to the Maine State Entomologist, and this is what they sent me. I thought it was interesting enough to reprint it here:
There have been several late winter reports of squirrels stripping the bark off of maples in Central and Northern Maine – and this is likely occurring across the state. One offered explanation for this is the increased sugar content of the inner bark at this time of year in trees like maples, basswood and elms.
Also, squirrel damage may be worse/more common this year due to the early summer drought of 2020, which may have caused trees to produce less seeds and nuts, limiting the squirrels’ food sources (i.e. hungrier than normal squirrels selecting less preferred food sources). Porcupine feeding may be more noticeable this time of year as well.
If you do not witness the creature in the act of stripping bark, there are ways to distinguish between the two based on teeth marks and bark strip size. Teeth marks smaller than 1/8 inch are typical of squirrels, while porcupine teeth marks are closer to 1/4 inch. Keep in mind, voles also are known to eat the bark of trees and shrubs, but this damage is usually located close to the ground, or even under the ground or mulch layer.
To discourage voles from girdling your trees, make sure you use tree guards through the winter months and don’t use too thick of a mulch layer to discourage burrowing. To discourage squirrels and porcupines, install a sheet of smooth tin/metal around the trunk of the tree roughly three feet from the ground surface.
This will only be effective if the affected tree is isolated and not in a clump of trees where squirrels and porcupines can climb a neighboring tree to access the tree on which they wish to feed. As these animals tend to favor a specific tree, discouraging feeding may cause the animals to pick their second favorite tree in your yard, increasing the number of impacted trees.
Comments are not available on this story.
Send questions/comments to the editors.
