Your Thoughts on Cutting this Tree

[kevin37b]

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 .

 

[s219]

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.

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.

 

[kevin37b]

What exactly is a barber chair . Is it a shear or a rotation ?

 

[Egon]

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.

 

[hunterridgefarm]

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.

You tell um Egon!:thumbsup:




urrr maybe your telling me

 

[CobyRupert]

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.

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.

 

[CobyRupert]

What exactly is a barber chair . Is it a shear or a rotation ?

http://www.youtube.com/watch?v=rGub5Jy1320

Look at about 1:35. They're pulling the top of the tree with a cable or rope creating a sheer force. A heavy leaner would have the same forces. The holding wood (hinge) is stronger than the sheer strength of the tree. The resultant stump looks like a barber's chair.

 

[TomSeller]

I have told this story a few times on TBN. I had a neighbor that had a big leaner over a bank down to his beach. He wanted to improve his view and wanted the tree gone. He would not listen to those of us that advised he hire a professional. Anyway, one day he went out and bought himself a big shiny new Stihl saw. He preceded to go up to the tree without even so much as back cutting the tree on the leaning side. Word has it that he was cutting directly from the away side of the lean with his head down by the saw when the tree barber chaired. Pretty much decapitated him the medics said. What ever you do, chain that trunk if you cut it. If it chairs on you, you may survive. Pictures from the Internet. Once upon a time I cut professionally. Very dangerous profession.

 

[MossRoad]

...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.

That's the part the give you the heeby jeebies, eh? You never know when something's going to drop on your head in the woods.

I recall one nice, sunny day in summer. I was probably somewhere between 18-24 as I was still living at my folks' house. My grandma lived across the driveway from us. I was out in the yard and heard a tremendous crash! I looked over at my grandma's house, and there she was, sitting on her covered porch in a rocking chair and about 10' away from her a LARGE forked branch about 30' long had snapped off an old oak about 70' up, and the fork came down. One fork pierced her roof through the porch ceiling and shattered on the concrete below. The other was stabbed into the ground. They were still connected above the roof and about 10' of branch was sticking straight up. Had she been at the other end of the porch.... YIKES!!!!

So, when you see damaged trees, get them down or have someone take them down, cause when a tree falls on you in the forest and no one is around to hear it.... you dead.

 

[s219]

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.

Normally, the barber chair "split" happens somewhere between the desired hinge and where the poor sucker starts his back cut, at the point where the back cut frees up enough fiber to allow the wood to shear and split under weight, and then catapult the butt.

With the "T", you have removed all the wood on each side, from the back all the way to the desired hinge. So the hinge is established 90%. What's left that could shear/split is just that narrow middle section of holding wood, and the split would never go across the whole tree to blow up like a barber chair.

No reason you couldn't cut that "T" with a plunge and then cut back. Would only add extra safety.

I have always done everything to avoid barber chairs when cutting a leaner, and haven't actually seen one happen in person. I have come across them from other people clearing hurricane trees though, and it's always interesting to see what the split looks like. I did cut a horizontal tree under a load once, and saw the same phenomena (ruined a nice furniture log that time). It was more like a gently pop, but the butt split a good 4-5 feet up the tree.

 

[s219]

http://www.youtube.com/watch?v=rGub5Jy1320

Look at about 1:35. They're pulling the top of the tree with a cable or rope creating a sheer force. A heavy leaner would have the same forces. The holding wood (hinge) is stronger than the sheer strength of the tree. The resultant stump looks like a barber's chair.

In that video, the real problem is that the notch angle is way too shallow. You will see that the butt doesn't split until after the tree goes over, and the split starts when the notch closes. In effect, they created their own leaner with that blunder. That one would have gone over just fine if the notch was much wider.

 

[dstig1]

s219, you are absolutely correct. The real bad thing, is all the trees they cut in the video looked that way. Very much too narrow face cut angles. They are asking for trouble. Kind of sad that seem to be "pros"...

 

[square1]

http://www.youtube.com/watch?v=rGub5Jy1320

Look at about 1:35. They're pulling the top of the tree with a cable or rope creating a sheer force. A heavy leaner would have the same forces. The holding wood (hinge) is stronger than the sheer strength of the tree. The resultant stump looks like a barber's chair.

A 2nd danger of a barber chair is shown in this video at ~2:45. If it doesn't decapitate you on the upswing, it may crush you on it's return trip
<shudder>

</shudder>
Respect the tree, it outweighs you, is faster than you, and has no conscience.

 

[CobyRupert]

With the "T", you have removed all the wood on each side, from the back all the way to the desired hinge. So the hinge is established 90%. What's left that could shear/split is just that narrow middle section of holding wood, and the split would never go across the whole tree to blow up like a barber chair.

I guess I'm thinking that the shear/split could start anywhere behind the chainsaw when you're sawing a backcut towards the hinge, whether there's a tee or the full width of the trunk still holding. If the tee "holds" and the sideways sheer forces are there, I still don't see why wouldn't a barber chair split open up from edge to edge across the trunk?

 

[Gary Fowler]

Seems like the trees tendency to split (barber chair) is a function of how much side tension (lean or rope pull) there is versus the adhesion strength between vertical grains of the tree. Perhaps I wrong, but I don't see where how it's dependent on whether you cut it high or low, other than if you cut it low it would give the top of the tree more leverage to split the grain.

Look at the photo at where it stopped splitting. Just cut it down below where the split stopped and you have the entire strength of the tree rather than just half of it.

 

[s219]

I guess I'm thinking that the shear/split could start anywhere behind the chainsaw when you're sawing a backcut towards the hinge, whether there's a tee or the full width of the trunk still holding. If the tee "holds" and the sideways sheer forces are there, I still don't see why wouldn't a barber chair split open up from edge to edge across the trunk?

The only "edge to edge" left is the thickness of the base of the "T". All other fibers that were under tension/compression have been severed. So at most, only the fibers within the base of the T can shear when you cut through the right plane. They are non contiguous with the rest of the tree, so the crack can't spread. You have sort of predefined the limits of the holding wood at that point.

 

[crazyal]

The only "edge to edge" left is the thickness of the base of the "T". All other fibers that were under tension/compression have been severed. So at most, only the fibers within the base of the T can shear when you cut through the right plane. They are non contiguous with the rest of the tree, so the crack can't spread. You have sort of predefined the limits of the holding wood at that point.

Just be careful that the heart wood isn't rotted.

 

[MossRoad]

A 2nd danger of a barber chair is shown in this video at ~2:45. If it doesn't decapitate you on the upswing, it may crush you on it's return trip
<shudder>

</shudder>
Respect the tree, it outweighs you, is faster than you, and has no conscience.

YIKES! Can't run fast enough!!!

The one at 1:00 pretty much disintegrates. But the one at 3:59 is the best.

 

[TomSeller]

YIKES! Can't run fast enough!!!

The one at 1:00 pretty much disintegrates. But the one at 3:59 is the best.

Right. Very dangerous profession and these guys are pros. Anyone know where most of that footage was filmed?

 

[MossRoad]

In the forest, DUH!