I had a vacant block behind a house I lived in years back. People bought the block and started getting ready to build. Biggest problem was a 30 foot tall dead gum tree. So one day I hear a lot of noise and a chainsaw being started so I went out the back to have a look. Here was the new owner with a few mates getting ready to drop the tree. They had tied a couple of ropes to it and had one guy on each rope. I've felled quite a few trees in my time and know how to read where they will fall. I also know the tremendous weight involved in a tree that tall. So I pointed out to them that one, the tree was going to fall and take out the neighbours fences and two, that two people holding ropes tied half way up the trunk had absolutely no chance of changing that. I was told less than politely to PO. It was pretty funny watching two people ripped off their feet as the tree came down and demolished the side and front fence and just narrowly miss the corner of the house next door.