Avoid evergreens, the tannins and oils can be toxic. Maple, oak, apple or cherry are all good woods to use for herps. Make sure the bark is smooth since you already have a noserubber. You might need to sand it down.
Also, don't forget to bleach it good to kill any insect eggs or hibernating buggies in there, then rinse like crazy.
The Zombie Mama is here!