...Couple things to note... the bags require support... a 5' sapling isn't stout enough to keep a full bag from toppling over and damaging the tree. A 5' sapling, grow tube, and 1/2" fiberglass tree stake won't hold a full bag if it isn't setting just right. I wound up adding a second stake to solve that problem...
I agree 100%. I just recently took the supports off a 8' Shumard Oak because those bags are heavy. 20 gallon bags X 8.33 are a little over 160 pounds.