Sometimes it difficult to judge by color alone, especially with the variety you're talking about. You may need to take a few pieces and scrape the bark away and smell the bark and wood. You can scrape off some shavings and smell the fresh wood, or put in a burned-out tin can and place over a burner or other heat source to get it smoking...smell the smoke and compare it to the other types of wood. You should be able to notice the subtle differences from the smoke aromas...hickory being sharp; apple sweet and mild; maple slightly sweet with a rich and earthy background, yet heavier than apple, etc.
It will be a process of elimination, and then determining which pieces match by color, grain and type of bark and sorting them out based on everything you've found to specific to that type.
Some of this may not seem like much help, but using the wood smoke has worked for me in the past...maybe not the best for actually identifying the wood, but does help to sort some species, at the minimum.
Eric