Personally I'd take that tree down in a heart beat. It has terrible structure and is way past its prime. ===>>> DITTO its going to be nothing but problems from here in out ... heck.. it doesnt even look like it gives any usable shade ... and the canopy looks very sparse.. but i dont know if that is the usual in your zone .. in winter ... be done with it ... its the end of the line for that one.. but it opens a vast potential.. for you to make your mark on this yard ... you can do so much better ... and.. unless its an optical delusion.. i wouldnt be surprised if the power company doesnt show up one day and torture it with some creative pruning .... sorry ... i am with the neighbor on this one.. and be sure to use it politically .. to make her a better neighbor .... a long story about how she is right.. and you are doing it all for her.. blah.. blah .... lol .. try to get some mileage out of it .. ken

yyou have a tree that is going to be significantly retarded in food production.. ergo vigor is going to be limited to the 1/4 inch strip .... it might take a decade to return to vigor .... you MIGHT be better off... cutting the whole thing off ... just below the danmage ... and letting it resprout some vigorous new shoots.. and then pick the best one or two and let them grow like rockets.. since there is no damage to the root zone ... wouldnt be surprised if you dont get one to go 6 to 8 feet by fall ... as compared to the one struggling for the next 5 years.. barely alive.. mending the trunk .... give it a go .. something new to watch and learn about ... its an experiment either way .... which do you prefer to learn about .... i will bet a buck [no pun intended] that you will have more trunk damage to watch heal ... so i vote for truncating [god.. another pun] the damaged trunk .. and watching it grow like a weed .... ken

Clump birch often lean. (Botann, this could be one tree that grows a couple of side trees, very common for some Birch, even in the woods where they grow naturally.) I can post a photo of mine and you will see the lean is pronounced on 2 of the 3. So far as the limberness of the tree, I think botann nailed it, too much fert when it was grown. This not only makes it suceptible to ice, but wait until a thunderstorm with cross-winds come through. You know all those nice long branches at the top? You will see some of them handing down alongside the trunk, broken but not down. Since River Birch lose their leaves pretty early, snow is rarely a problem. However, rain on the leaves adds weight, and the flimsy branches can break when the wind blows. Birch are fairly brittle trees. Where in PA are you?

A clump river birch is a river birch with multiple trunks. All the trunks should be from the same tree/root-system, but some cheapo nurseries stick single trunk specimens together for quick production. This practice (bundling multiple separate singe-trunk specimens together) frequently causes problems later as the trees grow and start splitting apart.