If you can believe it, it's near impossible to find a birch bark tutorial online. Yes, I was going to be lazy and look for one because I didn't have a lot of time or resources to spend experimenting. There were a few, but not with the end result I was going for, so I ended up coming up with my own. Which, I'm happy to say, I'm pretty pleased with.
An item to turn into "birch" -I used wooden purse handles
white flat acrylic gesso
black acrylic paint
brown acrylic paint
white school glue
(note I will be adding pictures)
1) Paint your item black. If you are starting with plain unfinished wood you don't need to be overly thorough with this, it can be a little sloppy. Allow paint to dry.
2. Paint item with a thick coat of school glue. Allow the glue to dry slightly so it's not overly goopy.
3. Dab your brush with white gesso and a bit of black and paint across your item in long strokes without overlapping as much as you can. This will create a nice cracking. If you want less of a crackled look go ahead and overlap a bit more. Try to apply it in a bark like effect (parallel horizontal stripes). Allow to dry (you can carefully use a heat gun to speed this up).
4. Add a very small amount of brown paint on your brush-wipe most of it off and using a dry brush technique, add a little brown over the white. This gives a cream color with a bit of brown. Allow to dry.
5. Highlight some areas where you want smooth unblemished white bark. Allow to dry.
6. Cover with a protective sealer.
7. If you want a more matte finish spray the sealed piece with a coat of matte clear coat.
Now you've got a birch look without flaying some poor tree!