Bark on maple tree glne
Thank you for the question. It's hard to say for sure what has stripped the bark in places on your tree. One possibility is squirrel damage since it looks quite shallow as far as I can tell and it's up high. Read about animals that strip bark: http://articles.extension.org/pages/10776/barkstripping
It can be a challenge to protect your landscape from squirrel damage but trapping and repellents might be good options. Read this article to learn about techniques in depth: http://extension.missouri.edu/p/g9455
If the bark hasn't been stripped all the way around the trunk, the tree may do well and recover from the damage. Keeping it well watered until the soil freezes and mulching around the base to protect from lawn mower and weed whipper damage. Do not paint over the damaged areas because research has shown that it is not helpful and may interfere with the tree's ability to heal itself.
Thank you for contacting Extension.