Rawhide glue is the best glue in my opinion that you can use for bonding any natural materials. I use it for lamjnating bows.
Check out "all bark and a lot of bite" in the bows category. I laminated the bow with bark and used hide glue to do it.
It is simple to make. All you have to do is boil rawhide ( cut into chip size peices). I use deer hide. When the water boils down , you'll get a caramel colored, thick (like cake batter) That is your glue.
Pour the glue into a shallow container and put it in the fridge overnight.
Next day, cut into thin slices and let it dry. It will turn hard.
Whenever you need some, you just warm it up in water and it will desolve back into hide glue.
It's great stuff!