Exactly which woods are poisonous to snakes?

I remember posts on wood shaving bedding that is poisonous to snakes (Cedar in particular), and have searched for the topic but can't come up with it. So, sorry if this is a dumb or repetitious question, but.....

Exactly which woods are poisonous to snakes? I am thinking of moving my boas to a wooden case, and want to make sure I don't use one made of toxic wood.

Similarly are there any branches to avoid using as furniture in the tank?

Thanks for any and all opinions, or just direct me to a source of information....

Sorry, just found this posting that duplicates mine, please forget my questions, I'll go to this thread.
Cheers

http://www.faunaclassifieds.com/foru...=Cedar+bedding