Well, if nobody knows the answer, I guess I'll just leave the tree as is. :)

Definitely, 100% confident it was not bumped by a lawn mower nor hit by a trimmer/edger. Trust me, if I hit it, lightly or hard, I'd be beating myself up for being such an idiot as I am exceedingly careful. lol. Now maybe a rock got thrown out by the mower but that's the only thing I can think regarding the lawn equipment. There were two stakes next to the tree that would've prevented the mower from getting that close to the side of the damage plus, like I mentioned, I do my own yardwork and am 100% confident I have not bumped or hit the tree with any thing. I am assuming squirrels because outside of neighbors cats and lizards, nothing else would typically be in my backyard. I've read from places, like this link/quote below, that squirrels will do damage. Ultimately, just want to not lose the tree and prevent further damage from occurring. http://icwdm.org/handbook/rodents/TreeSquirrels.asp "Squirrels may occasionally damage forest trees by chewing bark from branches and trunks. Pine squirrels damage Ponderosa pine, jack pine, and paper birch. In the Southeast, fox squirrels damage loblolly and other pines."

This is why people like me call these "junk trees". Left to their own devices, in many of North America's climate regions, they are usually short lived and very prone to storm damage. I've spent at least 30K in the past 15 years on tree services, largely dealing with these dogs (A. rubrum and A. saccharinum) that were planted or worse, allowed to grow from seedlings, by prior owners.* Probably 40% cleaning up storm damage, and the balance preemptively removing them to avoid future storm damage destroying valuable plants. The sugar maple (A. saccharum) is purported less awful, but I have no experience with them as they don't seem native to my my ecoregion in Maryland. If for some reason people want them in their yards, they should have a plan for very thoughtful pruning at every stage of the tree's development. Something that almost never happens. Maybe at the extremes of their natural ranges like Vermont, there is a case for planting them. Not here. And yet I bet 1/4 of shade trees planted in the Mid-Atlantic or Delmarva are a red maple. As some other threads have recently noted though, the country is becoming so dumbed down, it might be a lucky thing people even understand to plant shade trees anymore LOL. I myself have started to notice this "don't plant anything in a yard, and remove any trees" trend. Or the amusing trend of people cutting down the only nice tree they had in their yard, and leaving crap like red maples! Another thing I've noticed is some kind of dieback becoming more common. Not sure though if it's a disease in every case - sometimes it definitely appears to be - or just generalized stupidity. * not even counting small to mid-sized ones I handled myself, surely saving myself at least 5-6K. The $350 investment in a Stihl back in 2007 was a good one!

Hi there, Stax. Thanks so much for assuming I didn’t have a conversation with my own child. What a dumb comment to make. Last time I checked this wasn’t a parenting app? The point of the post was this: I know nothing about trees, especially River birch trees, some kids thought it would be fun to peel lots of bark off...does it look okay, in your experience, or should I maybe take action (I.e, wrap the tree, have someone come out and look at it). The only thing I know about tree bark it functions like somewhat like “skin” and is what provides nutrients to the tree and that a tree can be girdled or die from de barking. Simple as that. As far as I’m concerned how I handle the situation is my business only. I only explained what happened so that anyone who reads this post had context as to how the damage occurred. As for parenting, at the of the day all children should be taught by their guardians to respect other people’s property 🤷🏼‍♀️