I thought that I'd show some photos of the process for making Forest Shoes. The Northwest, willow bark is usually ready to harvest in late spring. It's a good idea to test a stick and make sure that the bark peels off easily.
Make 2 parallel cuts through the bark, to the wood.
If it's ready, the strip should slide right off.
Then you can peel back the rest of the bark, and remove it from the stick.