In the (perhaps vain) hope to provide some clarity where there has been a fair bit of argueing at cross purposes, animosity and name calling even resulting in a banning....let me revisit some of the points that I believe need to be carefully and clearly stated.
1. I don't believe Eric or anyone else has ever intended to encourage any un-trained unqualified persons through the watching of video on this forum to attempt to undertake
any type of tree felling. It is and will always be amongst the most dangerous things that you can be envolved in, it requires a lot of training under the watchful eye of fully qualified and experienced trainers, in a training environment.
2.
Noone has stated that trees should be felled in any other way than by following the scarf that is cut for them.....the scarf (or a perpendicular line from the middle of the scarf) gives the intended felling direction of the stem of the tree being felled.
3. What has been said is that in the particular case of felling a tree with a lean any offset position of the canopy relative to that perpendicular line will be reflected in the section of the tree after it is felled.
What eric has been saying is if you cut the scarf with this in mind you will be able to allow for that offset...thereby avoiding say an unmovable valuable object (the grey square) which would be struck if the offset was not accounted for.
The confusion and disagreement seems to be around the value or otherwise of the tapered hinge in all of this. I don't think anyone has said that a tapered hinge is not relevant to the success of the fell just that its influence on altering the final direction of the fell is absolutely minimal. The tapered hinge would still be used (IMO) even in the adjusted scarf to ensure that sufficient hinge/holding wood is retained through the fell...if not then John Dees scenario would be very likely...
Now in all of this I would like to add (or rather repeat) some things...every single tree that we fell is different to the last one felled....we have to take into consideration the assessed strength of the wood tissues the amount of lean (if any) and if that can be managed without canopy/weight reduction. There is only so much redirection possible irrespective of the technique being used, when dealing with leaning trees, without control lines, wedges levers and jacks most of the serious leaning trees I have dealt with would not have been fellable in any direction other than the way they were leaning. Attempting to direct the fell even marginally against the existing lean of a tree rightfully is classified as a complex fell.
None of what I have understood to be Erics adjusted scarf (or gun!) contradicts the industry standards (as limited and basic as they are) in any significant way....although if i have misunderstood please enlighten me.