I have received many emails regarding extensive damage to the bark of fully mature trees, particularly maples, this winter. The tree is stripped bare of bark in multiple places and sometimes this extends high up into the canopy.
Although the extent of this damage might suggest a large beast, the bushy tailed offenders are squirrels. Bark stripping has been linked to several squirrel species in North America including eastern gray (Sciurus carolinensis), fox (S. niger) and the red squirrel (Tamiasciurus hudsonicus).
Squirrels are opportunistic feeders. In addition to nuts and seeds, they eat small fruit, field crops like corn, insects, mushrooms, and are active visitors to bird feeders. Fox and eastern grey squirrels have been found to strip and apparently feed on inner tree bark as well.
In the northern regions, bark gnawing is most visible in the late winter months, but there have been reports of different tree species being affected throughout the seasons.
Stopping the squirrels isn’t a practical option in a forest setting. If the inner bark is removed all the way around a branch, that branch will die. If the inner bark is removed all the way around the main trunk of the tree the whole tree is most likely lost. A landowner may be able to protect an open-grown tree, with no buildings or wires close enough for the squirrels to jump onto the tree, by ringing the trunk with a 2-foot-wide metal collar about 3 to 4 feet off the ground.
For more information about squirrels and other nuisance animals, visit the Minnesota Department of Natural Resources at dnr.state.mn.us/livingwith_wildlife/index.html.
For other garden questions, call 320-762-3891 and leave a message, or email email@example.com.
Also, visit the Douglas County Master Gardeners Facebook page at: facebook.com/dcmastergardener for garden updates and virtual events.
Until next time, stay safe, happy gardening!
Robin Trott is a horticulture educator with University of Minnesota Extension. Contact her at 320-762-3890, or at trot0053@umn.