grover
Looks are correct, I am attached side D to side D. It is the prefered points of attachment for spur climbing. Being attached in this fashion is an idependant event, to having the tree split. If the tree splits up, down, or both will dictate the potetial of injuries you outlined.
Whilst lowering the winch down, I do have one flipline. The remainder of the cutting is done with two fliplines. If you look closely, during the scarf they are seperate, one primary and the other looser and seperate (less chance of cutting both at once).
During the back cuts they are load shareing and difficalt to seperate (perfect). If I have to descend down quickly for some reason (!), I have one less thing to fumble with.
The cutting in the back you have noticed is just a simple back cut, broken into a couple of segments. The ash are a very "touchy" tree to fall, let alone cut one in half without chaining it.
What will be the far side of the cut to the finnish, is quarter cut first. This means I am not trying to guess what wood is left, when the pressure is on to chase off the near side. In addition this commences the tree to release toward the scarf. Before I scoot around the back and finnish the cut I will often push the nose of the bar further accross the back of the hinge and neutralise the wood that causes "barbers chair".
These trees are often a fine line between just slowly going the way you want, and "barbers chair", it has become a melding of felling techniques. Oh, and by the way, you can't back release these unless you chain in two places below the cut. A defect six feet below your position could unexpectedly let the whole show go before you are ready. That strap from below simply picks up your fliplines, choked off lifeline and happiness, and drags you all to the ground. Bother.
Graeme