I enclose all of my cameras in metal 'security' boxes, which I mount on trees with wood screws. The boxes are to protect the cameras from bears primarily. But I had a bull moose rub the very Poplar tree I had a trail camera in. Mangled the metal box, but it protected that camera.
I had a bear bite the lens hood off one of my cameras, even with the metal box.
As to bears, there's a Grizzly Signpost, where I hunt (actually a power pole) that I found a couple years back, and continue to watch, and the top claw marks on that power pole are at least 3' higher than I can reach, which is about 8' give or take, standing on toes I can reach even a bit over 8' so those claw marks were something like 11'-12' high.
Which is to say that you're going to have a hard time in grizzly country protecting your cameras by simply placing them 'high' up a tree.
When I hang my cameras I don't concern myself with trying to hide my scent. I'm more interested in getting the camera postioned to get the shots I'm hoping for, and also locating them where 2-legged creatures (hopefully) won't find them. The bears will find your cameras regardless...
I've actually had 1 camera video 2 guys field dressing an elk right in front of the camera, and obviously they had no idea it was there.
I've only had 1 incident where a fella most definitely found one of my cameras, but he was polite enough not to tamper with it or steal it. But I still moved it as soon as I knew it had been found.