The second step for this tree is to cover it in a good layer of Durham's Water Putty, which you can easily get at a big box hardware store. You will find it with all the other "fix this hole" things on the paint aisle, and the 4 lb can runs just over or under $8, depending on where you are. This stuff dries harder than a turtle shell and it sets quickly, so work fast! It'll take a while to dry, generally overnight, but since I didn't putty mine last night, and Brae did, I busted out the blow dryer. :D I mixed it up in some sort of toss away cup that was left over from one of the birthday parties, used a craft stick to stir and the crappiest cheap brush I had to slather it on. This is a messy task, so if you want to try to do it later yourself, be prepared for mess. And whatever you do, do not rinse anything out. Talk about a clog in the drain! Us a cup/brush you can just toss in the trash.
I, incidentally, saved my cup of left over goop because it is carve-able, and I plan on carving mine into a boulder. :D
This stuff is so nice and easy to work with. I slathered it all up onto the trees base and made sure to cover all the nooks and crannies. I made sure to be especially thick on the trunk, so that I could shave it down smooth, and still hide the binding wire.
For a paper birch, this rough texture just won't do! I think I can fix this with a razor and file....