"No "step" is needed in the back cut of an open face notch because the hinge remains intact throughout the entire fall."
Not always possible.
Ever try cutting dead dried out snags, frozen wood, drought stressed trees etc?
Remember open face is a production technique for felling smaller second growth timber. Works fine there. Its compromises need to be understood just like the compromises made somewhere in every othe cutting method.
Not every tree/snag is capable of holding the hinge through a 70 degree + fall so when a bunch of verbiage comes out about "No "step" is needed in the back cut of an open face notch because the hinge remains intact throughout the entire fall" that is setting up the lesser experienced sawyers for failure.
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{However, with regard to the higher back-cut preventing all butt logs from kicking back. Take that with a grain of salt too.}
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Here is another thought that open face aficionados don't consider. What happens when you're dropping a bigger tree uphill on a fair slope and the hinge wood is still holding? Who you gonna send in there to cut that holding hinge?
Simply; there are also times you want that separation from butt and stump.
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How is a fire fighter going to jump a tree away from a helispot or fireline with the butt hanging on?
For some reason I get the impression open face doesn't include any of these thoughts in their training.
