Why not to angle your back cut?

[Lumber-Jack]

Actually I already stated a positive in my previous post. I nearly lost my foot because the tree was able to slide backwards off the trunk when the hinge broke prematurely while I was pounding a steel wedge in the straight (not angled) back cut.
Had I angled the back cut (even slightly) the tree base could not have slid backwards ,up and over, the angle when the hinge broke.
Obviously the hinge was cut to thin, but that's not the point, the point is that a (slightly) angled back cut has a "positive" safety feature when other things go wrong. And as long as one remembers that there is a "negative" by cutting at too much of an angle I believe a slight angle is a good thing, and I will continue to put a slight angle in my back cuts.

The point here really is that you made the hinge too thin and broke it off by pounding in the wedge. Also, the wedge may have been too thick to be effective, whihc may have also led to the failure. An angled back cut may have caused the tree to land entirely different, but with no better or more predictable results. The problem wasn't the angle, it was the hinge.

This brings up another issue on why a horizontal cut is best - all of the force applied with a wedge should goe to lifting the tree. With an angled cut, a portion of the force goes more in the horizontal, increasing the chances of breaking the hinge prematurely. Conversely, an angled cut with a wedge applies force to a narrow area on the stump and applies force away from the stump, possibly casuing the stump to split or fail below the wedge and loosing control of the tree. As someone else stated, it is easier to make a mistake with an angled backcut and getting below the felling notch.[/quote]

In this particular case the "problem" was that the branches of the tree I was cutting were intertwined with the branches of the trees branches surrounding it, thus the tree was reluctant to fall. yes I cut out a little more of the hinge, and ,,,, I also used a bigger wedge and,,, hit it a LOT harder then I usually need to That is what led to the hinge breaking. An angled back cut definitely would have stopped the tree from sliding off my side of the stump and nearly impaling my foot the way it did. I would much rather have had the tree fall over backward towards me, or side ways, at least when it does that you have time to react. When the hinge breaks like it did there is absolutely no time to react. The tree will not, can not, slide up hill, so there is no way it could have done what it did.
A couple more points to chew on; Not all trees are built the same, some are much more brittle than others and some trees are rotten in the middle, both can add uncertainty as to the strength and integrity of the hinge, so assuming all you gota do is cut the hinge correctly is not being very prepared for the unexpected. The other thing is, there is no such thing as a perfectly horizontal cut. Next time you go cut a tree down take your pocket level with you and check your "horizontal" back cut. Chances of it being perfectly level are next to nil. Will that effect your cut?, No. Why not? , because a slight amount of angle doesn't cause all the problems that have been mentioned. That being the case, then why not, since there is going to be some kind of slight angle anyway, why not make sure the angle is a slight down angle that will protect you in case of a unexpected hinge break.

 

[Mike PA]

Sure, an angled cut may have stopped it from sliding back. But, if there was sufficient force to slide it back, then there were plenty of other problems as well. Trees can, and do, slide uphill for various reasons, many times because it is caught up in other branches. I would agree that in the rare set of circumstances, an angled cut can help. In this case, you only know that the tree probably would not have dropped on your foot, you don't know what else may have happened, as the tree may have rotated off the stump and come down across your body. I'm not trying to tell you that a "slight" angle is going to get you killed. I was simply answering the original question of why you shouldn't do angled back cuts. Furthermore, the whole purpose of the hinge is to control the tree through the fall. You can do various notches, depending on how much control you want to have. If it comes down to an angled backcut keeping you safe, you need to look at other things that are going wrong and re-evaluate your technique.

 

[Cowboy Billy]

First of all you should never stand behind a tree when felling. Many times I've had tree fall on its branches they compress push the trunk 2-3 foot behind the stump and usually roll swinging the trunk either towards or away from me. With a angled back cut if the tree cannot move back and unload the pressure on it it could move sideways making it come at you. I have been running a saw for 34 years and I doubt there are many mistakes I haven't made and have seen a lot of crazy things happen. There are so many forces involved that its impossible to tell what will happen at times. You can usually make a good guess at what will happen and be right 90% of the time but there's still that 10% out there. Thats why its so important to have a clear area around the tree that you can move without tripping or getting hung up Being aware of everything around you and keeping good balance and being prepared to move. I can clearly remember cutting a tall strait 18" dbh poplar when I was 18. I cut through the hinge and it sat on the saw standing perfectly upright it spun 190 deg on my saw then fell opposite of where I wanted it to.

Billy

 

[Jags]

An angled back cut serves no positive purpose but it does have the negatives that TreePointer stated. There is no need to angle the back cut at all. It serves no purpose. You should not only make the back cut perfectly level but make it 2 inches higher than the hinge. It leaves a 2 inch step (Its called Stump Shot) to prevent the tree from sliding back when the hinge breaks. Another thing is to cut as wide a notch as you can. The hinge stays connected until the notch closes. At the very least take out a 45 degree notch. If you make a 90 degree notch the tree is on the ground when the notch closes and gives the ultimate in control.

If this practice was followed, tree jumping would be minimized because of a proper hinge "size" and the 2" stump shot. THIS is the proper way to fell a tree. This method also allows for adjustments to be made for direction if you need a twist fall, by allowing the hinge to be thinner or thicker on one side.

Thank you for posting mtcates.

 

[AbeAinPa]

Wow, when I originally posted this question I had no idea that it would start such a discussion. I thought the answer would be fairly cut (there I go again) and dry. I looked at the link provided a few posts back, a very good discussion by the way, thank you CJRages, and I learned a lot. Between that discussion and the one here I now consider myself among the converted, to horizontal back cuts that is. I'm a fairly technical person and the forces involved as described make sense to me. While there appears to be little down side, and maybe even a limited up side to a slightly angled back cut, I can now see that a significant angle is definitely something to avoid. I have always had success with my angled back cuts, but the increased risk of a barber chair or other incident scares the hell out of me. Thanks all for the lesson.

 

[charly]

That's the way I always was taught to make my back cuts too, 2 inches above to level with the front or face cut. Worked for two local tree services years ago, and then did line clearing for Almstead Enviormental Experts, and last was on NYS DOT's tree crew. The same cutting methods were used at all these places I worked. I think some people thought by using an angle cut, if they screwed up, it would keep the tree from comming over backwards! Yeh right!

 

[Lumber-Jack]

Billy brings up a good point which supports my thinking, and that is having a clear area to move should (when) something goes wrong. But of course for that option to work you need time to react, unfortunately when a hinge breaks like it did on me there is no time to react, it happened so fast, SNAP! the tree was imbedded in the ground an inch from my forward most foot. Had I been standing directly behind the tree (which I wasn't) I surely would have been hurt very badly.
A (slightly) down angled back cut is not going to keep you perfectly SAFE, please don't put words in my mouth, that's not what I'm saying.
For clarification I will repeat,,,,, Since it's nearly impossible to make a perfectly level back cut anyway (remember the pocket level) and you are bound to end up with a slight angle one way or the other anyway, and since a slight angle does not negatively effect the cut in the way a deep angle does, why not make sure you put a SLIGHT down angle. It won't keep you perfectly safe, but at the very least it will buy you some reaction time and add an extra measure of safety in case thing do go wrong.

And I have to disagree with Mike on the point that a tree standing vertical will slide uphill, sorry Mike it's not going to happen. Perhaps once the tree begins to fall, and hits another tree and the force of hitting that other tree pushes the trunk back, but that's a different mater, that can happen no mater what type of cut you make, and is something everyone should be prepared for.

 

[Mike PA]

For the trees sliding uphill, we seem to be dicsussing two slightly different things. As a tree is falling, it can slid uphill. I think we agree on that. I also agree that a perfectly vertical tree will not likely slide uphill, without other forces acting on it. So, something caused your tree to slide backwards. What was it? If you have an angled back cut and this situation happens, where does the tree go? Will it stay on the stump? Or will the angle of the backcut cause it to slip off one side or the other? Are you advocating a compound angle on your backcut, one slightly down to the front the other slightly away from you? Obviously, there were forces in the tree for which you were unprepared. I don't know if these were truly foreseeable or not, so this is not a judgement on your abilities. This is merely a question as to how much safety can really be derived from a cut such as this.

check this link for techniques:

(broken link removed to http://forestry.about.com/gi/o.htm?zi=1/XJ&zTi=1&sdn=forestry&cdn=education&tm=6&gps=288_349_1276_832&f=00&su=p284.9.336.ip_p897.9.336.ip_&tt=29&bt=1&bts=1&zu=http://www.osha.gov/SLTC/etools/logging/manual/logger/chain_saw/saw_use/saw_use.html)

Sorry, Link doesn't seem to work. type tree felling in the search feature and go to logging etools.

 

[basod]

Mike makes the point to a tee. With angled back cut, as the tree begins to fall and contacts tops of other surrounding it there is a lateral forcedplaced on the hinge. Depending on the tree and how hard you are working your saw back and forth nose to bucking spikes, there is no way to know how strong the interior fibers of the wood are. the pictorial above shows a good example of level cutting ground. On a downward slope lower cut of hinge sloud be steeply upangeled so as to prevent stump jump as tree falls past 50-70deg. with angeled back cut you are thinking the tree wont go backwards but your relying on some wood you can't see to prevent it from going left/right if it encounters resistance durning the initial fall. WhenI encounter this I leave more hinge wood left or right of the back cut to steer tree towards the side with more meat left in hinge. With a flat back cut if the tree hangs up it pops backwards and rolls left or right depending upon upward resistance. In these cases I'll spend 20-30minutes installing a tag line and preload the tree after noching it to prevent a dangerous situation.

 

[charly]

Mike makes the point to a tee. With angled back cut, as the tree begins to fall and contacts tops of other surrounding it there is a lateral forcedplaced on the hinge. Depending on the tree and how hard you are working your saw back and forth nose to bucking spikes, there is no way to know how strong the interior fibers of the wood are. the pictorial above shows a good example of level cutting ground. On a downward slope lower cut of hinge sloud be steeply upangeled so as to prevent stump jump as tree falls past 50-70deg. with angeled back cut you are thinking the tree wont go backwards but your relying on some wood you can't see to prevent it from going left/right if it encounters resistance durning the initial fall. WhenI encounter this I leave more hinge wood left or right of the back cut to steer tree towards the side with more meat left in hinge. With a flat back cut if the tree hangs up it pops backwards and rolls left or right depending upon upward resistance. In these cases I'll spend 20-30minutes installing a tag line and preload the tree after noching it to prevent a dangerous situation.

I hear ya with the tag line. The throw ball{bag} is my best friend. I've set plenty of lines with that. When I was clearing my land I use to plunge cut , bring the saw back but not out of the tree and then drop down on the back side, make a saw cut about 8 inches down. Then walk away from the tree, get to the other end of the line and pull the tree over by hand or with my tractor if need be. I was never near the tree, especially if there was a chance of stuff breaking out. Friends of mine on one tree crew I was on got to go to Arbor Master training, that's where they picked that up. Once we got the Bigshot and throw ball out, we rarely used the bucket truck to set a line. When in doubt rope it out!

 

[Lumber-Jack]

For the trees sliding uphill, we seem to be dicsussing two slightly different things. As a tree is falling, it can slid uphill. I think we agree on that. I also agree that a perfectly vertical tree will not likely slide uphill, without other forces acting on it. So, something caused your tree to slide backwards. What was it? If you have an angled back cut and this situation happens, where does the tree go? Will it stay on the stump? Or will the angle of the backcut cause it to slip off one side or the other? Are you advocating a compound angle on your backcut, one slightly down to the front the other slightly away from you? Obviously, there were forces in the tree for which you were unprepared. I don't know if these were truly foreseeable or not, so this is not a judgement on your abilities. This is merely a question as to how much safety can really be derived from a cut such as this.

check this link for techniques:

(broken link removed to http://forestry.about.com/gi/o.htm?zi=1/XJ&zTi=1&sdn=forestry&cdn=education&tm=6&gps=288_349_1276_832&f=00&su=p284.9.336.ip_p897.9.336.ip_&tt=29&bt=1&bts=1&zu=http://www.osha.gov/SLTC/etools/logging/manual/logger/chain_saw/saw_use/saw_use.html)

Sorry, Link doesn't seem to work. type tree felling in the search feature and go to logging etools.

Mike you have some good questions there, but let me get back to them. Got home late last night and found out we have an elderly friend is in the hospital, so I had to time to digest much else.
I shall return ;-)

 

[smokinj]

I heard that under some circumstances it can cause the tree to jump up kinda like having a ramp rather than fall off the back. I don't know but I haven't tried it either.

Billy

+1 one your just trying to tip the scale.

 

[AbeAinPa]

Here's a link to a good series of artcles by Arboriculture Canada Training & Education Ltd. who state that they specialize in practical training and certification for arborists. These articles pretty much back up and expand upon a lot of what many in this thread have been saying. Enjoy:

http://www.arborcanada.com/blog/technical-tree-felling-a-historical-perspective-article-1/

 

[mtcates]

There are a few people here defending the use of the angled back cut. I do tree work professionally as well as being a stump grinding subcontractor for many tree companies who just sub the stumps out. I know many many people who do tree work for a living and several more who do logging for a living. The guys in the industry who really know their stuff are the ones who always make a level back cut. Its the people with the least experience and knowledge who perform the angled back cut. The argument about the angled back cut stopping the tree from sliding back has very little merit. Its the "Stump Shot" that works many times better at doing so. Stump Shot, along with leaving enough hinge wood uncut is the most important thing to prevent loss of control when felling a tree.

For those of you who did not read the entire thread, Stump shot is the term for making the back cut at least 2 inches higher than the hinge of the notch. This leaves a vertical wall of wood 2 inches high behind the holding wood to prevent the butt of the tree from sliding back when the holding wood (hinge) breaks. This does several things if done correctly. First, it totally prevents the sideways force or shearing effect on the holding wood that will happen if the back cut were level or below the hinge. It takes far more force to pull the wood apart than to shear it. It makes the holding wood or hinge much stronger as it can only break by by the tree butt moving vertically. The only way the tree butt can move vertically is when the notch closes. As the tree is falling, when the notch closes, the holding wood is vertically pulled apart as the tree butt is lifted. If the notch cut was a 45 degree notch the tree will be exactly 45 degrees leaning in the fall when the holding wood starts to pull apart. If you cut a 90 degree notch, the tree will be on the ground and the holding wood will still be intact.

Now, If we were to try the same thing with the slanted back cut what would happen. If the tree had to be wedged over I would get some sideways shearing forces on the holding wood as I drove the wedge making the holding wood weaker. Also, if the slanted back cut were at a radical angle as i have seen some people do, the lifting force of the wedge would be compromised because the wood on the stump would split or crush as the wedge was driven. Thats two negatives of the slanted back cut. Wait, there is more. What if the feller decided to cut a little more wood to thin the hinge wood. Now you are messing with the height of the stump shot. As you cut deeper in the back cut to thin the hinge wood you are cutting down too making the 2 inch step now a 1 inch step. What if you were already almost level with the hinge in your slanted back cut and now you needed to thin the holding wood to make the tree fall. Then you would actually cut below the hinge wood. That is a very dangerous situation. Now as the tree pushes back as it falls, the holding wood can be sheared sideways and now the tree has a ramp to slide up and jump farther from the stump. Just as the earlier post stated. These things are more likely to happen than you think when performing a slanted back cut because it is very hard to judge the angle and where it will intersect with the hinge wood. If the tree has a back lean and starts to sit back the hinge wood has partial sideways forces trying to splinter and shear and the angle on the stump will bend and split if the forces are strong enough. The more sloped the cut the weaker the wood becomes in a back lean situation and the more sloped the cut, the more likely you are to screw up the safety factor of the stump shot.

With a level back cut, you can thin the hinge and you can taper the hinge, both without affecting the stump shot. You can drive a wedge to lift the tree without creating the side shearing forces on the hinge wood. With the level back cut you can drive a wedge without the wood on the stump splitting or crushing. Heck you can even cut a piece of wood out of the stump below the back cut in a big tree and use a hydraulic jack instead of a wedge. You can do all of these things without affecting the safety that the stump shot offers. If the tree sits back on the stump as you cut, the wood is stressed only in its two strongest axis which is straight up pulling of the hinge fibers and a straight down pushing on the stump. For those of you who only do a slightly sloping back cut, actually thats really not much different as far as forces are concerned as long as you don't slope more than 10 degrees or so. Heck, making a perfectly level cut is nearly impossible in the field. So a few degrees off is no big deal as it offers no plusses or minuses as far as safety goes.

In my professional opinion, as already stated earlier, the only time I use a slanted back cut is when I'm in the tree and cutting a near vertical piece of wood so it will slide off the slope and speer straight down. I have never seen a professional tree man at the top of his game ever use a slanted back cut felling a tree. But don't take my word for it. Those of you who do think its a better technique, I urge you to do more research because it is much safer to make a level back cut and your research will reveal this. Learn from those before you, before you get hurt.

 

[charly]

There are a few people here defending the use of the angled back cut. I do tree work professionally as well as being a stump grinding subcontractor for many tree companies who just sub the stumps out. I know many many people who do tree work for a living and several more who do logging for a living. The guys in the industry who really know their stuff are the ones who always make a level back cut. Its the people with the least experience and knowledge who perform the angled back cut. The argument about the angled back cut stopping the tree from sliding back has very little merit. Its the "Stump Shot" that works many times better at doing so. Stump Shot, along with leaving enough hinge wood uncut is the most important thing to prevent loss of control when felling a tree.

For those of you who did not read the entire thread, Stump shot is the term for making the back cut at least 2 inches higher than the hinge of the notch. This leaves a vertical wall of wood 2 inches high behind the holding wood to prevent the butt of the tree from sliding back when the holding wood (hinge) breaks. This does several things if done correctly. First, it totally prevents the sideways force or shearing effect on the holding wood that will happen if the back cut were level or below the hinge. It takes far more force to pull the wood apart than to shear it. It makes the holding wood or hinge much stronger as it can only break by by the tree butt moving vertically. The only way the tree butt can move vertically is when the notch closes. As the tree is falling, when the notch closes, the holding wood is vertically pulled apart as the tree butt is lifted. If the notch cut was a 45 degree notch the tree will be exactly 45 degrees leaning in the fall when the holding wood starts to pull apart. If you cut a 90 degree notch, the tree will be on the ground and the holding wood will still be intact.

Now, If we were to try the same thing with the slanted back cut what would happen. If the tree had to be wedged over I would get some sideways shearing forces on the holding wood as I drove the wedge making the holding wood weaker. Also, if the slanted back cut were at a radical angle as i have seen some people do, the lifting force of the wedge would be compromised because the wood on the stump would split or crush as the wedge was driven. Thats two negatives of the slanted back cut. Wait, there is more. What if the feller decided to cut a little more wood to thin the hinge wood. Now you are messing with the height of the stump shot. As you cut deeper in the back cut to thin the hinge wood you are cutting down too making the 2 inch step now a 1 inch step. What if you were already almost level with the hinge in your slanted back cut and now you needed to thin the holding wood to make the tree fall. Then you would actually cut below the hinge wood. That is a very dangerous situation. Now as the tree pushes back as it falls, the holding wood can be sheared sideways and now the tree has a ramp to slide up and jump farther from the stump. Just as the earlier post stated. These things are more likely to happen than you think when performing a slanted back cut because it is very hard to judge the angle and where it will intersect with the hinge wood. If the tree has a back lean and starts to sit back the hinge wood has partial sideways forces trying to splinter and shear and the angle on the stump will bend and split if the forces are strong enough. The more sloped the cut the weaker the wood becomes in a back lean situation and the more sloped the cut, the more likely you are to screw up the safety factor of the stump shot.

With a level back cut, you can thin the hinge and you can taper the hinge, both without affecting the stump shot. You can drive a wedge to lift the tree without creating the side shearing forces on the hinge wood. With the level back cut you can drive a wedge without the wood on the stump splitting or crushing. Heck you can even cut a piece of wood out of the stump below the back cut in a big tree and use a hydraulic jack instead of a wedge. You can do all of these things without affecting the safety that the stump shot offers. If the tree sits back on the stump as you cut, the wood is stressed only in its two strongest axis which is straight up pulling of the hinge fibers and a straight down pushing on the stump. For those of you who only do a slightly sloping back cut, actually thats really not much different as far as forces are concerned as long as you don't slope more than 10 degrees or so. Heck, making a perfectly level cut is nearly impossible in the field. So a few degrees off is no big deal as it offers no plusses or minuses as far as safety goes.

In my professional opinion, as already stated earlier, the only time I use a slanted back cut is when I'm in the tree and cutting a near vertical piece of wood so it will slide off the slope and speer straight down. I have never seen a professional tree man at the top of his game ever use a slanted back cut felling a tree. But don't take my word for it. Those of you who do think its a better technique, I urge you to do more research because it is much safer to make a level back cut and your research will reveal this. Learn from those before you, before you get hurt.

I agree. Anytime I've seen stumps along the road cut like that, I knew they were done by an occasional cutter, or home owner.

 

[Lumber-Jack]

There are a few people here defending the use of the angled back cut. I do tree work professionally as well as being a stump grinding subcontractor for many tree companies who just sub the stumps out. I know many many people who do tree work for a living and several more who do logging for a living. The guys in the industry who really know their stuff are the ones who always make a level back cut. Its the people with the least experience and knowledge who perform the angled back cut. The argument about the angled back cut stopping the tree from sliding back has very little merit. Its the "Stump Shot" that works many times better at doing so. Stump Shot, along with leaving enough hinge wood uncut is the most important thing to prevent loss of control when felling a tree.


With a level back cut, you can thin the hinge and you can taper the hinge, both without affecting the stump shot. You can drive a wedge to lift the tree without creating the side shearing forces on the hinge wood. With the level back cut you can drive a wedge without the wood on the stump splitting or crushing. Heck you can even cut a piece of wood out of the stump below the back cut in a big tree and use a hydraulic jack instead of a wedge. You can do all of these things without affecting the safety that the stump shot offers. If the tree sits back on the stump as you cut, the wood is stressed only in its two strongest axis which is straight up pulling of the hinge fibers and a straight down pushing on the stump. For those of you who only do a slightly sloping back cut, actually thats really not much different as far as forces are concerned as long as you don't slope more than 10 degrees or so. Heck, making a perfectly level cut is nearly impossible in the field. So a few degrees off is no big deal as it offers no plusses or minuses as far as safety goes.

In my professional opinion, as already stated earlier, the only time I use a slanted back cut is when I'm in the tree and cutting a near vertical piece of wood so it will slide off the slope and speer straight down. I have never seen a professional tree man at the top of his game ever use a slanted back cut felling a tree. But don't take my word for it. Those of you who do think its a better technique, I urge you to do more research because it is much safer to make a level back cut and your research will reveal this. Learn from those before you, before you get hurt.

That’s good information MTcates, although the bold highlighted area basically repeats some of what I was saying.
To elaborate on my circumstance, described earlier in this thread and to answer Mike’s questions, I had made a series of mistakes (isn’t that how most tragedies happen) in cutting that led to the tree doing what it did. Keep in mind I was trying to do a horizontal cut, not an angled cut, but as I (and MTcates) pointed out it is nearly impossible to do a perfectly horizontal cut, and I ended up with a slightly upward sloped cut, the opposite of what everybody is talking about here. That was the first mistake, then that back cut ended up not being the prescribed 2” above the front notch cut (second mistake), then as I have already pointed out I cut too deep and left very little hinge. Then of course I pounded a couple wedges in and and the hinge broke prematurely, when it did it came to rest on top of the steel wedge and shot it out the back like a watermelon seed between your fingers as the tree slipped down the slight slope of the stump on the backside and came to rest beside my foot.
My whole point is, had I deliberately made a (slight) down slope angle, instead of an upslope angle, I could not see that have happening. Obviously if you are a professional who’s very proficient with a saw and you are able to make perfect cuts every time, you don’t have to worry about things like that, but for me at that time (about 30 years ago) this was not the case.
I hate to repeat myself again, but in view of what MTcates said in the bold highlighted area, and what happen to me in the past, I still advocate initiating a (slight) downward slope to the back cut, rather than horizontal cut that might inadvertently become a slight upward slope.
I've never had anything like that happen in the 30 years since, so thus far it seems to be working.