When I was 15-16, I started cutting for a full time logger, doing firewood and pulp. I had already been doing firewood for my dad (just home use) for a few years. Other than bucking, my boss wouldn't let me touch a saw until I took the 2 week course that was held by the province. I learned quickly that I had been doing things all wrong. Even after the course, I was not allowed to fell without supervision by the boss or my older brother (Whom had been cutting for 5-6 years at that point) for about 2 months. I learned quickly that the course didn't teach you everything. Leaners are dangerous even when you know what you are doing. I no longer cut for a living but have always cut my own firewood. Leaners still make me nervous. I have a giant maple on my property that I have been avoiding for years. Its about 50'' plus at the base, 70' plus tall, with a good 45 deg. lean, and about 36'' center is hollow. I keep hoping the next storm will take it down. There is another maple near by that is about the same size, looks solid, but is 2 trunks coming from 1 stump. They have somewhat grown together and spiral together, but there is still a split that will easily separate the two, if I try to cut it. I have put a lot of trees on the ground safely over the years, but also know my limits. I don't pretend to be a pro so I will leave these ones to mother nature. Has anyone reading ever safely dropped a giant spiral pair.