I made a short recurve of red oak.   Actually out of a stick that the two high school guys passed up.  In short, it cracked.  A nice, long splinter running in off the back.  I glued it, and backed the bow with heavy brown grocery bag material.   I cracked again.   I glued it again and covered the area with more bag.  It cracked again.......
So, I resorted to the old "sinew on a spool", dental floss.   Unwaxed, plain white.  Wrapped on in close winds for 3/4 inch or so over the end of the splinter and then over wrapped back the beginning.   I dosed it with thin cyanoacrylate.  Now it's holding.  I may put a wrap to match on the other limb, just to keep balance in the universe.  
It's not that I NEEEEED that bow.  I just thought I may as well try to save it and learn something in the process.  Knowing how to repair this sort of damage might come in handy sometime.  
piper