Tully, a straight-through cut is better, although sometimes not always possible if a top starts twisting in the wind etc, or the climbers work position is awkward. Steps cuts are ok on horizontal's because the crane is able to exert so much leverage that there’s very little shock-loading. This is also handy where one is looking to keep the section moving up, often referred to as a ledge-cut in the US....but then you must remember if you’re adding a balancer/sling just outside the cut then it should be set much looser than the other slings, otherwise your leverage is lost and a shock-load will incur.
If you do step-cut a top or vertical section then the cross-over between the two cuts is always better positioned on the compression side of the load, so maximum leverage is gained when cabling up. Step cuts are also useful when working with inexperienced tree-crane-operators, who feel more at ease in the fact that you are out of harm’s way while they make the lift. I’ve used step-cuts on many, many jobs with great success....although careful slinging and accurate pre-loading are imperative.
Tree-related crane-training is hard to come by. Mark Chisholm does workshops in Norway from time-to-time as already mentioned, and Mayer Tree Service in the US have just recently done similar: TreeBuzz Board: North American Hands -On Climber/Crane Training
If you are a competent, conventional tree rigger, then you can carry much of that over to tree/crane removals....doesn’t make you anywhere near qualified but it’s a good place to start. I was lucky to have lots of opportunity at a young age and have always been very comfortable with it, although it’s not for everyone. We're just scratching the surface here really, it’s a broader subject than a lot of people realise.
I have hosted some crane work on youtube if you’ve the time to scroll through my account: YouTube - ????? Recoates
there’s not too many verbal explanations but you should still be able recognize similar patterns and techniques throughout. Hope that helps.
Simon we were done for lunch but didn't rush to leave the site.
Thanks again