I understand this but I just feel that while there aren't many (if any) studies of the effects of pine oils on reptiles specifically, the multitude of other studies done on various species that conclude the detrimental effects of exposure make it relatively safe (for me at least) to assume it's not safe for cold-blooded animals either. At the very least, we don't know definitively whether it's safe or not, and that uncertainty combined with related research that it's unsafe for a vast variety of animals and the experiences of others just raises a bit of a red flag for me.
I get that it's a practice a lot of people use and that some people (perhaps most) have never experienced issues with pine shavings. I guess I'm just of the mind that just because they haven't had an issue yet doesn't mean they wont later on, or that perhaps things ARE occurring but just not being noticed or attributed to the pine oil. Long term low dose exposure to even mildly toxic materials can have detrimental effects much further down the road, decades even. Kind of like all these medications that are FDA approved safe after a 5 year study that causes cancer or other issues that develop maybe 15 or 20 years down the road. We just don't know, and it's hard to document the exact cause of the ailment in these situations because of the relatively short timeline we put on disease processes and the long timeline for the exposure to the possible causative agent.
Idk. I'm rambling. It's a "to each their own" situation, everyone keeps their snakes differently, but for me I interpret the evidence as pointing towards pine being unsafe, at the very least not optimal. I personally would never keep my snakes on pine simply because I don't even want there to be a possibility of their lifespans being shortened by a decision of mine. Just my 2 cents, I'll stick to aspen and newspaperthanks for the link, it's an interesting read