If you had taken your time to read what I said, it's already been said & you don't have to go too far back to read it either. The reasons for why this method has been pushed by the trainers hasn't yet been explained, but I'd be saying that it is a safety aspect, which is front & foremost these days & the sacrifice of a little time to achieve it is the price industry has to pay to reduce accidents, workers comp payments & industry deaths. Our logging industry 30 years ago was full of hillbilly cutters killing themselves hand over fist, then they gradually changed the industrial laws, so that now if anybody is negligent in their duty of care they can be sued for millions in a common law court for negligence, that goes from the land owner up the chain to the owners of the mill, that's why they implement training programs to cover their arses, but they still want the job done cheaper every year which is a total contradiction & the only way around to make money is mechanisation, or the people doing the job will have to take shortcuts, from what I can see some are defending the later.
But back to the question, it's safer because the wedge has less chance of bouncing or skewing out of where it's being driven into, plastic on plastic only has 1/2 the resistance of bouncing out of the cut as one with timber friction on each face & the incline of the slope is double that of a single wedge which isn't working in the favour of stopping a wedge bouncing out. If wedges bounce out there is more chance of the hinge breaking when the tree sits back down with force, which leads to a Faller being caught by a tree going the wrong way with no escape route, not all fallers may back up their doubled up wedges to prevent this happening or had a few close calls to learn what to do from a near miss. Statistically 1 in 2 million minor incidents will cause a fatality in the building industry, forestry is probably twice as dangerous as that at least.
Thansk
Because the government says makes it right?
Yes wedge on wedge has more likely hood to pop out, but it is manageable, both when backed up, and by using just a touch of dirt between wedges, simple easy method that doesn't waste time under a crippled back leaner.
Also I've never had the hold wood fail backwards, I've cut too much off yes, and I've had it fail sideways, but a wedge will hold it from going backwards if the cutter doesn't cut all the hold wood, and with back leaners i always leave more hold wood anyway, despite if it requires me to beat the wedges a little harder.
Only once have I had a tree sit back after lifting off the wedges, and it was being pulled by a cheap rope that broke, luckily the hold wood did its job. that and the kung foo wedge toss from 3 feet away that kept it from tipping all the way back. Now I tighten up a few wedges before pulling even with cable.
The point you seam to be missing is that boring under your back cut, only removes material you need to lift the tree, causing you to use more wedge, 3 cuts is equal to about one wedge in thickness, so now you have used three wedges where 2 could have done it, and probably broke one in the process. but since you can't drive them deep enough, now you have to add a forth... and where exactly is that going to go? ya just going to bore under those three wedges and stuff another one in there? I think not, in fact I know yer not cause I understand physics. meanwhile said tree is crippled hanging on to whatever hold wood is left, just waiting for the next strong breeze to send it wherever it wants to go.
To sum up, once you have the back cut started is the most dangerous time in falling timber, it can and will go at any time, there are no hard and fast rules that say 2" of hold wood is going to hold this 12000 pound stick in the air while I **** about whittling on the stump. So yes there is a chance that a plastic wedge will pop out, that is why you use at least 2 stacks, but at least you get the tree leaning the right direction as quickly as possible. In my book, and considering the type of logging I do is far more important then making sure some ass nine rule made up by some pencil pusher in an office is followed.
Also if you can't judge the lean of a tree be it crown weight, lean, limb, head, belly, whatever and you've been cutting for more then 3 weeks, hang it up before you get killed.
