kevin37b
Veteran Member
How old are you ? Do you have a wife , kids ,grandkids ? Get a trackhoe in there and knock it over . Remember one OS moment is all it takes . You are too busy for this . Just saying .
I see how a Coos Bay might make it easier to control the release when you do the back cut, but I don't see how doing a back cut (Step 4) from outside the tree, towards the hinge eliminates barber chair.
Without a holding strap on the outside edge of the trunk, farthest from the hinge, it would seem the tree is in danger of barber chairing.
Go cut the darned thing off as low as possible using the traditional methods. Just be careful and don't bind the saw blade on the wedge cut.
It'll probably hang up when you down it.
I see what you mean if you're thinking that cutting the strap last in a typical plunge cut is what prevents the barber chair. But really, the trick is to eliminate the tendency to create a strong point shear load, which is what sets off the barber chair. In the case of a bore/plunge cut, you do that by hollowing out the holding wood where the shear would start. In the case of the Coos Bay, you have removed the sides of the holding wood, which is probably 90% of the wood that would setup that shear action, and you have disconnected the wood fibers between top and bottom. The little bit left in the base of the "T" is inconsequential. There is no longer a continuous shear plane across the wood to let go.
If you visualize the holding wood left in the "T" and think about what happens when you finish up by nibbling away the base of the T with a back cut, you can picture what wood fiber is left to hold and potentially shear, and see that it's limited to only what's left in that thin base of the T. Even if that did shear, it's a limited area not connected to enough other wood fibers to split across the whole trunk.
What exactly is a barber chair . Is it a shear or a rotation ?
...The part that broke off showed no signs of disease and broke off early one morning no wind. I just felt lucky it did not fall while I was driving under it.
Ok, I follow you. I think? I think what you are saying is that the tensile strength of the tee-part you leave is hopefully less than the sheer force required to barber chair? I don't get the : "Even if that did shear, it's a limited area not connected to enough other wood fibers to split across the whole trunk." ???
Wouldn't it be better to cut the tee of your coos bay with a plunge cut behind the hinge and cut back?
Though, I can see that even with a plunge cut, once you cut the strap, if the hinge is too thick, you could still barber chair.