While doing a very large cotton wood removal, there was a very serious "near miss" incident. One chain from the crane was choked to a central leader of a top with 2 other leaders included in the pick (5000lbs+-). The climber then rapped down and made the cut. After the cut was made, the large top inverted and came free of the chain, falling and missing the climber by 5ft. Needless to say this would of been a fatality. Thoughts are welcomed. Thank you.