The second part is partialy correct. I t depends on how long, species, climate etc.. One may be punky in the middle and the next two may be solid! There really is no way to know until you make a cut, and even then until it is on the ground sometimes!!! I once was taking down a live Oak, about 10" across, small tree, I told everyone to clear and one of the guys was "I'll be fine, I am watching you" IDIOT!!!! I told him to move a few more times, he wouldn't, bigger IDIOT!!! I cut the tree. Made my notch and it came over!! He did a couple of belly rolls and barely got out of the way, his saw didn't fair so well!!:hmm3grin2orange: The tree was hollow with only about 3/4" all the way around it holding it up. He will not argue with me anymore, if I even let him go!!!
It just goes to show, you never know what will happen and always be carefull!!!
Andy