I've never had a bear bother my food but I have had the elfin bears do damage. Most problems with food are from user error.
I have left food out and walked away to do something and a Trail Camp Marmot, a different breed as far as I'm concerned, walked away with all my breakfast foods.
You don't need a canister above the tree line. However, your food has to be hung so the little non-climbing varmints can't get to it.
