High Back Cut, Burnham Style!

[DMc]

Great job, Burnham.

That's a great illustration of even when you do everything just right, things can go wrong. And why in residential work I have often pieced a tree instead of trying to flop it in one piece, depending on the targets.

Those little stubs in the hinges can play havock at times.

There were no targets with this tree but the hidden stub swung the placement 10 to 15 degs. Things like that can be disastrous around a house.

Dave

 

[gf beranek]

Nice pic, Dave. It's funny just how many times I put the undercut up to such included knots and not see any clues of their presence until the tree is down, and not always where it was supposed to be.

Redwoods have a tendency for pockets of included bark. Which everything appears to be normal until the trees breaks over to the holding corner.

Defects in the region of the hingewood is a major player for misses to the lay.

 

[Burnham]

Hey B. please educate me, why the high back cut???

Stump shot.

Paul, I think it's more to keep the tree from shooting back over the stump if the top gets hung up or hits something. With that much weight and momentum, it's coming down. And if the top can't go forward then the butt is coming backward.

As Jay identified by the term, and Brian defined, stump shot is provided by placeing the back cut higher than the horizontal cut of the face, either standard or humbolt style. The ledge that results serves as a curb that the butt of the tree will hang on if the top strikes another tree out in the lay and is driven backwards. Lots of fallers have taken that kick backwards and not lived to tell the tale.

I just said "will hang on"; that's not a given, but it does increase the odds in your favor.

A higher back cut provides a bigger curb...so in especially tight lays I'm inclined to increase the height.

That offset in elevation between the floor of the face and the back cut also tends to increase the time the hinge functions well, allowing more flex forward as the tree commits to the face.

As in most things, you can overdo it. The stump pictured in this thread is what I'd call maximum stump shot...36" diameter wood, 5" stump shot. Average would be about half that, and many production fallers go for minimum or no stump shot to save wood and save a bucking cut to flat the end of the butt log, assuming use of a humbolt face.

 

[rumination]

Average would be about half that, and many production fallers go for minimum or no stump shot to save wood and save a bucking cut to flat the end of the butt log, assuming use of a humbolt face.

Is stumpshot really at all necessary with a humboldt face? I always figured the lower diagonal of the face was enough for the trunk to push back against without any need for stumpshot. That's why I always use a humboldt when felling a top through other trees, to keep it from kicking back and to allow the butt to just slide down off the face if it does get hung up. It's worked quite well for me. There's been many occasions when I've had a top go over and then just stop, leaning on the branches of another tree. Cutting through the hinge and pushing the butt off the face sends it to the ground.

 

[Burnham]

Burnham, do you think it would've wedged over easier if you'd used less stump shot?

No, in general. I base that on the age and species, Justin. Old growth Doug fir usually has nice straight grain and few knots at the butt, so the hinge functions about the same as the fiber splits vertically down the back of the hinge in short or tall hinges.

Yes, in this specific case. If I'd used minimal stump shot, the back cut would have come in under those internal stubs and avoided their effect.

 

[Burnham]

Is stumpshot really at all necessary with a humboldt face? I always figured the lower diagonal of the face was enough for the trunk to push back against without any need for stumpshot. That's why I always use a humboldt when felling a top through other trees, to keep it from kicking back and to allow the butt to just slide down off the face if it does get hung up. It's worked quite well for me. There's been many occasions when I've had a top go over and then just stop, leaning on the branches of another tree. Cutting through the hinge and pushing the butt off the face sends it to the ground.

You're in good company in that belief, Leon...but personally, I disagree. The way I see it, the diagonal slope of the lower face cut serves as a wonderful ramp to direct the butt up and over the stump if it does get pushed backwards.

I guess it all depends on the angles. If the butt is pushed back into the slope of the humbolt face when the two surfaces meet flat to each other, or earlier in the fall, then your view makes sense. If it happens later in the fall, then I think my view is more likely correct.

 

[rumination]

I had not thought of it that way before, Burnham. Thanks, I'll be considering that whenever I make a humboldt from now on.

 

[SkwerI]

But if the tree hits an obstacle later in the fall, there is a lot less chance of the tree kicking back because it will be falling almost straight down. I'm not saying it can't happen, but if the tree is already past 45 degrees then the chances of it kicking back are about nil. Unless you're falling it up hill.

 

[darkstar]

Or its shaped like a naner.
a bananer.

 

[Bounce]

A cut shaped like a banana? I don't get it.

 

[Burnham]

But if the tree hits an obstacle later in the fall, there is a lot less chance of the tree kicking back because it will be falling almost straight down. I'm not saying it can't happen, but if the tree is already past 45 degrees then the chances of it kicking back are about nil. Unless you're falling it up hill.

Fair enough.

A cut shaped like a banana? I don't get it.

I think Dark means if the tree is shaped like a banana.

 

[darkstar]

"I think Dark means if the tree is shaped like a banana. "
Correct , if a tree is shaped like a naner and it falls on the bowed side , shs gonna jump like Jordan when she hits the ground.
Killer Trees.
There is no method for avoiding that jump, best to be a long ways away.

 

[woodworkingboy]

Burnham also mentioned in his original post that the tree had some back lean. It seems like with back lean, a high back cut option usually automatically offers itself into the decision equation, either when using wedges or when pulling....more hinge wood to bend in the direction of the fall for the tree to stand on before breaking (seems like I may have read that somewhere, JB). When you say that with the high back cut here, though, with this species, it doesn't take any more effort to wedge over, before breaking, it seems like it basically negates the purpose of the high back cut related to lean, unless you also try to leave a beefy hinge. A wider hinge with this species, would seem more purposeful than a tall one when getting the tree leaning in the right direction, but then likely there really will be more effort required to wedge it over. I don't know that you want to be banging on a rotten tree so much though, it could bust off before the lean is corrected...? Can we say a beefier hinge with pull trees, and lesser so with wedged ones, depending on wood condition and species? Perhaps it's making it more complicated than it needs to be?

I like the combination of a high back there, along with cutting it up so fine, given the other trees limbs in the vicinity and also wanting to throw it across the road, as long as you were seeing the lean being corrected as you progressed with the cut, like you said. It requires a watchful method.

 

[squisher]

That offset in elevation between the floor of the face and the back cut also tends to increase the time the hinge functions well, allowing more flex forward as the tree commits to the face.

No, in general. I base that on the age and species, Justin. Old growth Doug fir usually has nice straight grain and few knots at the butt, so the hinge functions about the same as the fiber splits vertically down the back of the hinge in short or tall hinges.

But if the hinge is 'stronger' with a tall back cut wouldn't that extra strength add more resistance to the tree wedging over? Or do you think that that hinge strength being slightly better due to the higher backcut is really negligible in how much effort it takes to lift the tree over? Not trying to argue, just trying to learn. Doug firs are my favorite tree to fall.

 

[woodworkingboy]

I don't think that you can talk about a high back cut related to the effort to get the break started, without also figuring in the width of the hinge as well, along with how the grain runs.

 

[squisher]

In my question we'll assume that the only varying factor is the height of the backcut.

I thought that went without saying but I guess not.




Just giving ya a razz Jay but I hear what you're saying.

 

[woodworkingboy]

Yeah, I was kind of thinking that too, but why not complicate things.

 

[Gord]

I think the worst thing about a high backcut is the difficulty in judging hinge thickness. Not really anything left on the far side. I'd shave the bark to get a better view.

Nice shot Burnham.

 

[Burnham]

But if the hinge is 'stronger' with a tall back cut wouldn't that extra strength add more resistance to the tree wedging over? Or do you think that that hinge strength being slightly better due to the higher backcut is really negligible in how much effort it takes to lift the tree over? Not trying to argue, just trying to learn. Doug firs are my favorite tree to fall.

I don't think stronger is the right term here, Justin. I say the higher back cut provides a hinge that flexes a bit easier/more. A more flexible hinge wedges over easier than a stiff hinge. And a hinge with no stump shot is not as flexible.

 

[Burnham]

Burnham also mentioned in his original post that the tree had some back lean. It seems like with back lean, a high back cut option usually automatically offers itself into the decision equation, either when using wedges or when pulling....more hinge wood to bend in the direction of the fall for the tree to stand on before breaking (seems like I may have read that somewhere, JB). When you say that with the high back cut here, though, with this species, it doesn't take any more effort to wedge over, before breaking, it seems like it basically negates the purpose of the high back cut related to lean, unless you also try to leave a beefy hinge. A wider hinge with this species, would seem more purposeful than a tall one when getting the tree leaning in the right direction, but then likely there really will be more effort required to wedge it over. I don't know that you want to be banging on a rotten tree so much though, it could bust off before the lean is corrected...? Can we say a beefier hinge with pull trees, and lesser so with wedged ones, depending on wood condition and species? Perhaps it's making it more complicated than it needs to be?

I like the combination of a high back there, along with cutting it up so fine, given the other trees limbs in the vicinity and also wanting to throw it across the road, as long as you were seeing the lean being corrected as you progressed with the cut, like you said. It requires a watchful method.

My only comment in all this is I don't really buy into your premise that a high back cut is dictated when back lean is present. Maybe so, I don't know, but for me that isn't part of the equation when planning a felling cut.

 

[Burnham]

I think the worst thing about a high backcut is the difficulty in judging hinge thickness. Not really anything left on the far side. I'd shave the bark to get a better view.

Nice shot Burnham.

That's pretty close observation there, Gord. I had to examine that myself, when I post-mortemed the stump. I actually didn't overcut the off side, but the punky wood on the outer corner broke off the butt instead of holding with the rest of the hinge and sure makes it look like I did cut it off in the pic, and on the stump.

And I did chop the bark off over there .

 

[woodworkingboy]

Just thinking that I'm going along with your premise that a high back cut gives more flexibility to a hinge, therefore more time to move in the direction of the lay before breaking....but along the lines of my earlier rambling post, I think that a beefier hinge is better than a high back cut when pulling trees to the lay, assuming you have the power to mitigate it's strength to not want to bend. With wedges, it seems a somewhat different arrangement.

Certainly, the degree of back lean is a factor in all this, and in the tree in question's case, the back lean appears fairly minimal.

Not questioning your method here at all, Burham, just trying to add some variables for study. Personally, I'm still unclear on the dynamic differences when pulling vs wedging.

I seem to remember Jerry writing that he liked a thick hinge with a high back cut for back lean. I don't remember exactly in what context he was saying this.

 

[squisher]

So aiming for a 2" backcut height(if WCB is coming out ) is more of a production falling guideline would you say? To minimize waste while still maintaining an acceptable safe level of stumpshot. And if so then in your opinion do you think it would be better to use a higher backcut most of the time in a residential setting?

I'm interested in your opinion on this Burnham as backcut height being to low is one of my most common errors. Not coming in under the face or anything but I was taught with a humboldt and a backcut that would basically fell a tree so the buckerman would have little to nothing to do with the butt. As close to even as possible without coming in under. When you have a good lay and favorable lean it's really easy to do. As things become more challenging or dangerous I move more to favoring the 2"s, but I've never been into really tall backcuts. Since doing residential work I always aim for about 2"s on my backcut.

I hear what you're saying about the flexing being a better term then strength. Although it would seem it translates, when paired with proper felling cuts, into a more effectve hinge then but shouldn't be any harder to wedge over. And in your opinion if anything it's easier to wedge over than a lower back cut?

Also I'm curious when you say 5" is sort of max height. What are your reasons for determining that max back cut height? I guess what I'm wondering is why after a certain point then does it become less efficient? And of course I'm wondering about these things as they concern a residential setting where generally a few inchs of wood is not a money or waste issue.

Again Burnham I'm just curious and appreciate the time and thought that you put into answering questions.

 

[MasterBlaster]

 

[squisher]

Heh you can never know to much about felling a tree. I enjoy the cutting threads.