Okay, I have built a hundred of these things in the past out of bamboo.........but I picked up some christmas trees today (couldn't resist) and I was wondering how much sacrete does it take to sink a 7 to 8 foot cedar tree that probably weights 50 pounds. The base of the trees are about 6 inches across. I'm going to use 5 gallon buckets to hold the trees because I want them to stand up on the bottom. Thanks for the help.