Impaction from substrate is caused by poor husbandry, not from loose substrates. Do your due diligence. It is not seen in the wild because no flawed conditions exist in the wild.
I am sorry, but Tom is not the only expert in tortoise care. He is however the only one who belittles people for questioning him. I am done with this group.
Orchid bark is pure bark, but it is fir tree bark. I have also been told by 4 different turtle/tortoise group admins not to use it because it is toxic. I was also told to use a 50/50 organic top soil/coco coir mix by all four. I am amazed that any tortoise survives with so much conflicting...