What I did do however was to have the head or branching part and the roots cut off, saving the center trunk section. Wasn't sure what I was going to do with it until I figured I could cut it down, cut part of it out and make a planter out of it. It could become the center piece of a table on the deck.
I let the thing dry out in the basement, soaping the ends so that they wouldn't split too much as they dried. They split and it wasn't dried out much almost 8 months later. I cut it down to a 24" piece then I placed it on my drill press and used my largest Forstner bit to drill over lapping holes. I used a tool that has a cutter that oscillates to put deep straight cuts where I had market it for the rectangular hole. The bit got hot creating steam that was actually very hot momentarily as it cut. The wood was still very moist and would clog the bit sometimes if I tried to go too fast. I ended up doing this procedure twice to get the depth I wanted. I may take one more cut this winter to get more dirt space.
After getting the bottom flat I brushed on some stain to try to seal the wood and I used a paste wax on the ends and the bark to just give it some protection. We went to Lowe's and bought 4 cacti, something I had no experience with other than hens and chickens of which I really had no experience with in reality. Oh, and the feet are a 1" piece cut in 1/2 and notched into the underside of the log.
The end result is this. Finished this about 2 weeks ago and so far they seem to be doing okay. The red bloom is new and it looks like there may be more coming.