Head Leaner

[Greener]

I will be felling an alder which majorly favors the lay (front lean). The trunk has about a 16-18 inch diameter at the base. I plan to drop it in the direction of the lean. My plan is to do the face cut over 50 percent in, or until it just starts to pinch. Finish the angle cut. Then nip each side of the face just a bit before doing the back cut. I initially planned to leave a taller hinge, but then thought a smaller hinge would actually reduce the risk of barber chair with this approach. See attached.

 

[BC WetCoast]

You don't need to go in 50%, 30% will be fine for your face cut. When you do your back cut, don't stop part way through. You have to power through your cut until you get to your hinge width. That's the easiest way to prevent a barberchair. There are fancy falling cuts you can use, but powering through your backcut is easist.

Just for the record, WorkSafe BC doesn't recognize any other falling cuts ie bore cuts.

 

[Greener]

You don't need to go in 50%, 30% will be fine for your face cut. When you do your back cut, don't stop part way through. You have to power through your cut until you get to your hinge width. That's the easiest way to prevent a barberchair. There are fancy falling cuts you can use, but powering through your backcut is easist.

Just for the record, WorkSafe BC doesn't recognize any other falling cuts ie bore cuts.

In a tree with a bit less head lean I could see value in this approach. But whether you hammer through the back cut quickly or not is not as important as the degree of lean, and therefore, the tension and bind on the lower trunk. This one has close to a 45 degree lean in at least half the tree. Won't the sheer pressure from the lean be a more important factor than the speed which I get through the back cut?

 

[pdqdl]

The concept behind "cut faster" is that the barber-chair split generally initiates at the weakest point of the un-cut trunk. If you happen to be cutting fast enough to go past that point before the tree can BC, then you have dodged that bullet. I think that philosophy works well with big timber conifers, but I don't think it's always the right plan.

I'd stick with your initial plan. I very much prefer a deep notch to avoid BC events. Like you said, stop cutting when the gap begins to close. Then do a back cut at the same height as your face cut.

I think you may have problems getting that tree to come down. Looks like it'll hang up in a bunch of other trees.

 

[oscar4883]

Boring it and popping it off the stump won't hurt and is easy to do. If you are really concerned about the amount of head lean you can always rig a holding line opposite the lean and release it at the appropriate time.

 

[lfnh]

I think you may have problems getting that tree to come down. Looks like it'll hang up in a bunch of other trees.

Yup, unless 'on the ground' shows a opening, you'll end up with
a hanger and alot more work of a different sort.
Cut a opening for your lay and hit it.

 

[Greener]

The concept behind "cut faster" is that the barber-chair split generally initiates at the weakest point of the un-cut trunk. If you happen to be cutting fast enough to go past that point before the tree can BC, then you have dodged that bullet. I think that philosophy works well with big timber conifers, but I don't think it's always the right plan.

I'd stick with your initial plan. I very much prefer a deep notch to avoid BC events. Like you said, stop cutting when the gap begins to close. Then do a back cut at the same height as your face cut.

I think you may have problems getting that tree to come down. Looks like it'll hang up in a bunch of other trees.

I think the more top lean, the higher the risk of a chair effect because it is not the "weak" part of the tree the determines when/if it chairs out, it is the degree of lean and the amount of weight leaning and putting bind and pull on the trunk. Don't you think?

On the hang up issue: it is hard to see in the photo but there is a gap in the adjacent trees just to the right of the lay. I think I can put it through the gap. Worst case, drag it out with the tractor, though.

 

[Greener]

Boring it and popping it off the stump won't hurt and is easy to do. If you are really concerned about the amount of head lean you can always rig a holding line opposite the lean and release it at the appropriate time.

Not a bad idea.

 

[pdqdl]

I think the more top lean, the higher the risk of a chair effect because it is not the "weak" part of the tree the determines when/if it chairs out, it is the degree of lean and the amount of weight leaning and putting bind and pull on the trunk. Don't you think?

No, that's really not true.

In general, a tree trunk is composed of wood under compression and that same wood undergoes periodical tension when the wind blows. Head leaners are a bit different, in that parts of the tree trunk are always under tension.

When you fell a head leaner in the direction of lean with a conventional shallow face cut and deeper back cut, you are mostly removing the tension wood and placing tension on the compression side of the trunk. This leads to a barber chair event.

By cutting the compression wood out from underneath the head leaner, you are eliminating most of the compression wood, and putting much larger strain on the tension wood. If it fails at that point, the tree does not barber chair, it just falls over. The wood doesn't split, it just breaks off. That is why you place a deep face cut on the head leaner.

The "bore cut" philosophy is to adhere to shallow face cut methodology while reducing the risk of BC. I suppose that is the best way to maximize lumber profits and never break the stem of a good log, but it isn't the best way to eliminate the risk of barber chair.

 

[climberjones]

Why not throw a heavy ratchet strap around it and eliminate all the bs?

 

[rmh3481]

I would use the Coos Bay cut on that one. You basically keep shaving away until it folds. No chance of a barberchair. Here is a video so you can see the idea.
YouTube - Leaner Technique

 

[Greener]

No, that's really not true.

In general, a tree trunk is composed of wood under compression and that same wood undergoes periodical tension when the wind blows. Head leaners are a bit different, in that parts of the tree trunk are always under tension.

When you fell a head leaner in the direction of lean with a conventional shallow face cut and deeper back cut, you are mostly removing the tension wood and placing tension on the compression side of the trunk. This leads to a barber chair event.

By cutting the compression wood out from underneath the head leaner, you are eliminating most of the compression wood, and putting much larger strain on the tension wood. If it fails at that point, the tree does not barber chair, it just falls over. The wood doesn't split, it just breaks off. That is why you place a deep face cut on the head leaner.

The "bore cut" philosophy is to adhere to shallow face cut methodology while reducing the risk of BC. I suppose that is the best way to maximize lumber profits and never break the stem of a good log, but it isn't the best way to eliminate the risk of barber chair.

Yes, good explanation. I appreciate you taking all the time with it. With a deep face cut, most of the compression wood it gone. But the more lean, the less deep you can get on the face cut and the more pressure there is pushing the trunk sideways and out toward the back cut, and thus, the more wood that can potentially still be in the trunk when a split happen. The funny thing that after all this talk about the lean, my problem will probably end up being a hang up and I'll have to pull the butt with the tractor. Ultimately, I got a lot of information on leaners here and that is much appreciated.
Colby

 

[Greener]

Why not throw a heavy ratchet strap around it and eliminate all the bs?

Too simple and not as much fun.

 

[John Ellison]

I would use the Coos Bay cut on that one. You basically keep shaving away until it folds. No chance of a barberchair. Here is a video so you can see the idea.
YouTube - Leaner Technique

That is not a Coos Bay cut. The video shows a method some use to disable small dia. spring poles. Using it on a standing tree of any size would be very slow and not have much directional control.
Coos Bay is basically side cuts that are fanned or bored leaving a strip of holding wood in the center that is at 90 deg. to the face or dir. of lean.

 

[pdqdl]

:agree2:

I'll go a bit further: that "shave the trunk" was done by some idiot making a movie just to get airtime on u-tube. The cut shown was unnecessary and impractical, it wasn't done on a head leaner, and the tree wasn't big enough to be too big a risk for barber chair even if you did nothing but back-cut the tree with no face cut whatsoever.

I never cease to be amazed at how almost all of the countless chainsaw "how-to" videos are made by folks that don't know what they are doing.

I might add that a deep face cut functions the same way as the silly video posted above, except that it is done in a practical manner, and it works well on larger trees.