Your Thoughts on Cutting this 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!