Part of an introduction to the science behind tree felling, this video covers hinge terminology and offers a basic explanation of what to aim for. Produced with CyberLink PowerDirector 11
Thank you sir for putting your time and effort into these videos. I've learned more from watching 3 of your videos that I did working 6 months for a tree company that didn't explain nothing but cut and run as fast as you can... Thanks again.
Thanks, Bobby. I've urged a couple of the more mainstream arborist sites to go ahead and produce a series of educational videos specifically to orient ground crews on safety, hardware, etc. It would be a big undertaking and no takers yet. I feel it would be a really useful series. One company has put some videos together, but more is needed.
Terry. You know the best thing about your knowledge...Your going to save a lot of lives & prevent people from injury. There are a lot of novice individuals out there that don't know there @#$ from a hole in the ground when it comes to cutting down trees. Great job on your videos. Thanks for your expertise.
Thanks, Joe. That is my hope and was my motivation for making the videos. My fear is that a lot of those novices are inappropriately confident and don't feel the need to research something that they see as a simple action.
Hi Terry, We have a lot in common, engineering and cutting trees. My Logging began in previous generations beginning in Humbolt Co., Eureka CA. , two generations later I am in the Quinault Rain Forest in western wa. After being drafted into the army my education led me into civil engineering, designing roads, Land Surveying and administrating contracts for the USDA Forest Service. After six years with the feds I fell back to the profession of my forefathers. It was in my blood and have been cutting timber for close to 40 years. I can't describe the contentment of being self employed in the timber industry. However I keep my Theodilites, edms in shape for the occasional request of locating property boundaries. I particularly enjoy performing Polaris observations in determining meridians. I enjoy your scientific approach in describing the art. Take Care! Mark
Terry thanks a los for letting us have all these helpful videos is always something new l've been a tree climber since l was l6 and now l wish a could have a certificate as a tree climber so eventhough l have studied these videos are going to improve my knowledge abou tree procedure thanks Terry god bless you att Roberto Gomez.
Shouldn't the notch be cut deeper than the tree's vertical CG? Seems to me that is the only way for the tree to not pinch the back cut without wedges, winching, etc.
You don't have control over (and usually don't know) where the c.g is. You pick a direction to fell the tree in and make the hinge perpendicular to it. It's best to keep that hinge towards the side you want to fell it in. If you cut it too deep, you may have guessed wrong on where the c.g. is. The extra width for the back cut gives you better options to use wedges.
Well done ! ... for a start in the physics / setup if the notch. Leads me to next think about physics of 1) "barber chairing" 2) importance of noting "lean / speed" of tree top vs. speed of backcut to maintain control of direction of fall, and safety
I've cut a lot of trees, and until seeing your videos I thought I knew what I was doing. I do appreciate the engineering approach to what you present. Although the same thing applies- I thought I was an engineer until...
I am just starting to watch your series, and am extremely impressed with your thoroughness! I always knew there is a huge amount of physics involved, but have never seen anybody else cover it all so exactly! We need every advantage in something so risky with so many "unknowns"! Thank you!
You sir know your stuff and love your teaching style. Hats off where did you gain as much knowledge as you have Terry. I’m going to take a guess, woodlot manager as your career and maybe gravitated towards an arborist. Not like I work in an office myself
Good on you for putting in the effort for these videos Terry. Very informative and indepth, I have learned alot and look forward to putting it all into practise. Cheers
Hi Terry. I'm trying to understand why a notch depth of 1/3 the diameter is typically recommended. As you show in the drawing around 3:37 into the video, a perfectly balanced tree wouldn't fall on it's own with the notch cut 1/3 of the way in. A wedge is necessary to move the tree to the point where the center of mass will be over the pivot point (which, btw, you show as being at the back of the hinge... wouldn't it really be somewhere in the middle of the hinge?). In fact, with the cuts made as shown in that drawing, a wedge(s) is REQUIRED to keep the tree from sitting back on the chainsaw bar. Intuitively, I would think you'd want to cut the notch back further, until it's past the center of mass of the tree, so that the tree will start falling on it's own once you make the back cut. Of course, there's probably no such thing as a perfectly balanced tree, so you'd have to vary the depth of the notch depending on lean. But I keep wondering why the 1/3 diameter depth is recommended so much, without reference to whether the tree is leaning or substantially straight. Can you shed any light on this for me? Thanks for the great series of videos!
Keith, You pretty much nailed it with "there's probably no such thing as a perfectly balanced tree". If the tree is well balanced, cutting 1/3 of the way through is likely to make it lean a bit to that side. After all, in theory, the full width of the trunk is under compression from the weight of the tree and you just removed the support on that side. With a well-balanced tree, a wedge is typically not needed. Even with a lot of experience, what looks like a well-balanced tree can trick you. I'd say the 1/3 is a reasonable ballpark number; certainly not something requiring precision. Considering how frequently cuts don't cooperate on where to join, the 1/3 should be viewed as little more than a target. If you cut the depth to 1/2 the diameter, you're probably doing a lot of extra cutting. Additionally, unless you're dealing with a large tree, you may be running out of space for your wedges in the back cut. If you cut to less than 1/4, your hinge length is starting to get short and you will have reduced resistance to the tree falling sideways. If you know you have to deal with a back leaner, you may want to use a shallower notch. That way, you will have a large couple (distance) between your wedge and your hinge. That will act as leverage and reduce both the stress (tension) on the hinge and stress (compression) that has to be overcome when driving your wedge in. Bottom line, all things being equal, 1/3 is a good target, but not something to get stressed over.
Your forgetting that the quality of wood can vary and if there is sn unknown rotten core, cutting a half diameter notch would be a disaster. A 1/3 notch ensures a likely good hinge
Very appreciate that you make so detailed explanation about tree felling technique!!! I am a forest worker from Taiwan and i am trying to make some tutorial film in mandarin chinese . Can I cite some of your explantion when i translate these information? Thanks for your help!!!
What is risky about deep notch? The only thing I can think of is baiting the chain. (Ofc. it requires a lot of cutting but when I don´t want to use wedges and so the deep notch seems like the only option).
You are correct. If a cutter misjudges the tree, it could settle and squeeze tight on the chain/bar. Similarly, the tree could begin to fall before the feller is ready to do the back cut.
Great video, comments are very helpful also.....so, the deeper the notch, the wider the hinge, and the less risk of tree falling sideways, right ? The deeper the notch the safer it is.... deeper is safer ?
Thanks David. Relative to side lean, Yes, a wider hinge is safer. If lean or back lean are significant factors, it gets more complicated as removing a large notch weakens the tree's ability to resist those leans. Shallow notches are needed for leaners, as covered in "Leaners".
Just found your channel and have been doing a bit of a binge watch as I have a lot dead ash trees on my lot that need to be safely removed (darn emerald ash borer). As a guy who grew in a city your videos have been very helpful. PS Just guess but are you are science teacher?
You warm my heart, as your are my target audience. I hope you have a fireplace as dead standing ash is a great firewood. If forest grown, it splits really well. Not a bad guess, but I'm a civil engineer and computer programmer. I do love to teach. I hope all the removals go well for you!
great videos I was wondering if there is a formula that could roughly work out the amount of movement produced at the top of a tree by wedging at the base of the tree?
Thanks Alex. For almost two months, UA-cam was hiding comments from me. I finally discovered that last weekend and began responding to them. Yours "required" the lengthiest response I have yet attempted. I was a few lines shy of sending it when it suddenly converted into a tiny electromagnetic puff of heat. Needless to say, I was quietly, but highly, pissed off. It gave me an aversion to trying again until tonight. If this attempt also disappears into the ether, you will hear the explosion and have no idea what that was. In answer to your question, I am practically certain there is no such formula. However, a mathematically true, but physically flawed, formula can be worked out. First, we have to define some variables. Let Ht be the height of the tree in feet. Let Kw be the width of the kerf for your back cut. (Assume 3/8") Let Ww be the width of your wedge measured in inches, right at the point where it enters the wood of the trunk. Let Ma be the moment arm, measured from that same point, perpendicularly to the effective center of the hinge you have cut. Let Tm be what you want to find, the feet of movement at the top of the tree. Given those variables, the theoretical formula would be: Tm = Ht x ((Ww - Kw)/Ma) As an example, say you have a 70 foot tall pine tree (Ht = 70) Say the distance from where you wedge enters the trunk to your hinge is 7" (Ma = 7) Say your wedge is 1" thick at the end, but you have only driven it in to where it is 3/4" thick. (Ww = 3/4). Remember that 3/8" of that is "wasted" just replacing the wood you removed making your kerf. Applying the formula, we get: Tm = 70' x ((3/4 - 3/8)/7) or Tm = 10' x 3/8 = 3'-9" Unfortunately, this ignores some physical issues. The most important one is that wood is not inelastic. Prior to your cutting and wedging, the weight of the tree was supported by the entire area of the cross section. Due to your vicious attack, that weight is now supported only by the hinge and your wedge. Given that you are needing to wedge it, the pressure that the wedge is exerting on the wood is quite a bit higher then the pressure on the hinge wood. As a result, the wood at the hinge compresses somewhat and the lift is reduced. The movement at the top might be reduced by half. You can, however, improve the situation by driving additional wedges. With three wedges, the stress on the wood at each will be reduced to about a third of what the one was feeling and you will get closer to your theoretical lift. The compressibility of the wood will vary significantly with species, density, moisture content, and any rot.
thank you very much for your answer it is a great help. when felling in tight situations I like to roughly work out all possibilities by measuring the tree size and I always wondered if it was possible to to figure out how much lift I would have to produce on a back leaning tree to tip the balance.
Yeah. Sorry 'bout that. I won't compete with a stream again. Also, it turned out that my camera was set to Autofocus. Works fine for still photography, but adds a bunch of noise if you're taking video.
Definitely agree. I had no idea the microphone would pick up the noise so well. Won't do that again. Unfortunately, it was only one of several sound issues I've had to work on on the videos.
Thank you sir for putting your time and effort into these videos. I've learned more from watching 3 of your videos that I did working 6 months for a tree company that didn't explain nothing but cut and run as fast as you can... Thanks again.
Thanks, Bobby. I've urged a couple of the more mainstream arborist sites to go ahead and produce a series of educational videos specifically to orient ground crews on safety, hardware, etc. It would be a big undertaking and no takers yet. I feel it would be a really useful series. One company has put some videos together, but more is needed.
Terry. You know the best thing about your knowledge...Your going to save a lot of lives & prevent people from injury. There are a lot of novice individuals out there that don't know there @#$ from a hole in the ground when it comes to cutting down trees. Great job on your videos. Thanks for your expertise.
Thanks, Joe. That is my hope and was my motivation for making the videos. My fear is that a lot of those novices are inappropriately confident and don't feel the need to research something that they see as a simple action.
I am so humbled to realize there could be so many considerations when cutting a notch.
Hi Terry,
We have a lot in common, engineering and cutting trees. My Logging began in previous generations beginning in Humbolt Co., Eureka CA. , two generations later I am in the Quinault Rain Forest in western wa. After being drafted into the army my education led me into civil engineering, designing roads, Land Surveying and administrating contracts for the USDA Forest Service. After six years with the feds I fell back to the profession of my forefathers. It was in my blood and have been cutting timber for close to 40 years. I can't describe the contentment of being self employed in the timber industry. However I keep my Theodilites, edms in shape for the occasional request of locating property boundaries. I particularly enjoy performing Polaris observations in determining meridians.
I enjoy your scientific approach in describing the art.
Take Care!
Mark
Mark, Years ago, my wife and I made a hike to Lake Quinault and cherished the experience. I can absolutely appreciate your choice. Nice!
Terry thanks a los for letting us have all these helpful videos is always something new l've been a tree climber since l was l6 and now l wish a could have a certificate as a tree climber so eventhough l have studied these videos are going to improve my knowledge abou tree procedure thanks Terry god bless you att Roberto Gomez.
I've watched most of your videos several times, and each time I watch I pick up something new. Thanks!
Thanks for that!
This will take me a few times to fully grasp. Thanks, its exactly what I need.
You have my permission to watch it several times. lol.
Shouldn't the notch be cut deeper than the tree's vertical CG? Seems to me that is the only way for the tree to not pinch the back cut without wedges, winching, etc.
You don't have control over (and usually don't know) where the c.g is. You pick a direction to fell the tree in and make the hinge perpendicular to it. It's best to keep that hinge towards the side you want to fell it in. If you cut it too deep, you may have guessed wrong on where the c.g. is. The extra width for the back cut gives you better options to use wedges.
Well done ! ... for a start in the physics / setup if the notch. Leads me to next think about physics of 1) "barber chairing" 2) importance of noting "lean / speed" of tree top vs. speed of backcut to maintain control of direction of fall, and safety
I've cut a lot of trees, and until seeing your videos I thought I knew what I was doing. I do appreciate the engineering approach to what you present. Although the same thing applies- I thought I was an engineer until...
Thanks G. Sometimes it's nice to get confirmation of why your practices are good.
I am just starting to watch your series, and am extremely impressed with your thoroughness! I always knew there is a huge amount of physics involved, but have never seen anybody else cover it all so exactly! We need every advantage in something so risky with so many "unknowns"! Thank you!
Thanks Steve.
Best description on youtube
You sir know your stuff and love your teaching style. Hats off
where did you gain as much knowledge as you have Terry. I’m going to take a guess, woodlot manager as your career and maybe gravitated towards an arborist. Not like I work in an office myself
Thank you for the in-depth analyses. However, isn't the second notch shown the Conventional Cut and not Open Face? Cheers!
Good on you for putting in the effort for these videos Terry. Very informative and indepth, I have learned alot and look forward to putting it all into practise. Cheers
Much appreciated Max.
I've watched a million of these videos. I only subscribed to yours. Great job I enjoyed it..
Thanks Andrew!
Great Video and info! Thanks!
Thank you, John!
🔥🔥🔥
Hi Terry. I'm trying to understand why a notch depth of 1/3 the diameter is typically recommended. As you show in the drawing around 3:37 into the video, a perfectly balanced tree wouldn't fall on it's own with the notch cut 1/3 of the way in. A wedge is necessary to move the tree to the point where the center of mass will be over the pivot point (which, btw, you show as being at the back of the hinge... wouldn't it really be somewhere in the middle of the hinge?). In fact, with the cuts made as shown in that drawing, a wedge(s) is REQUIRED to keep the tree from sitting back on the chainsaw bar.
Intuitively, I would think you'd want to cut the notch back further, until it's past the center of mass of the tree, so that the tree will start falling on it's own once you make the back cut.
Of course, there's probably no such thing as a perfectly balanced tree, so you'd have to vary the depth of the notch depending on lean. But I keep wondering why the 1/3 diameter depth is recommended so much, without reference to whether the tree is leaning or substantially straight.
Can you shed any light on this for me?
Thanks for the great series of videos!
Keith, You pretty much nailed it with "there's probably no such thing as a perfectly balanced tree". If the tree is well balanced, cutting 1/3 of the way through is likely to make it lean a bit to that side. After all, in theory, the full width of the trunk is under compression from the weight of the tree and you just removed the support on that side. With a well-balanced tree, a wedge is typically not needed.
Even with a lot of experience, what looks like a well-balanced tree can trick you. I'd say the 1/3 is a reasonable ballpark number; certainly not something requiring precision. Considering how frequently cuts don't cooperate on where to join, the 1/3 should be viewed as little more than a target.
If you cut the depth to 1/2 the diameter, you're probably doing a lot of extra cutting. Additionally, unless you're dealing with a large tree, you may be running out of space for your wedges in the back cut.
If you cut to less than 1/4, your hinge length is starting to get short and you will have reduced resistance to the tree falling sideways. If you know you have to deal with a back leaner, you may want to use a shallower notch. That way, you will have a large couple (distance) between your wedge and your hinge. That will act as leverage and reduce both the stress (tension) on the hinge and stress (compression) that has to be overcome when driving your wedge in.
Bottom line, all things being equal, 1/3 is a good target, but not something to get stressed over.
Your forgetting that the quality of wood can vary and if there is sn unknown rotten core, cutting a half diameter notch would be a disaster. A 1/3 notch ensures a likely good hinge
Very appreciate that you make so detailed explanation about tree felling technique!!! I am a forest worker from Taiwan and i am trying to make some tutorial film in mandarin chinese . Can I cite some of your explantion when i translate these information? Thanks for your help!!!
Certainly! Also, feel free to copy any of the content you want. Bless you for your efforts to help other people.
thank you very much!
the victorious yamani eo
What is risky about deep notch? The only thing I can think of is baiting the chain. (Ofc. it requires a lot of cutting but when I don´t want to use wedges and so the deep notch seems like the only option).
You are correct. If a cutter misjudges the tree, it could settle and squeeze tight on the chain/bar. Similarly, the tree could begin to fall before the feller is ready to do the back cut.
Great video, comments are very helpful also.....so, the deeper the notch, the wider the hinge, and the less risk of tree falling sideways, right ? The deeper the notch the safer it is.... deeper is safer ?
Thanks David. Relative to side lean, Yes, a wider hinge is safer. If lean or back lean are significant factors, it gets more complicated as removing a large notch weakens the tree's ability to resist those leans. Shallow notches are needed for leaners, as covered in "Leaners".
@@terryhale9006 very interesting; and great info. -- thanks for the instruction !!!! Have to check out that video also.
Thanks for the video!
Just found your channel and have been doing a bit of a binge watch as I have a lot dead ash trees on my lot that need to be safely removed (darn emerald ash borer). As a guy who grew in a city your videos have been very helpful.
PS Just guess but are you are science teacher?
You warm my heart, as your are my target audience. I hope you have a fireplace as dead standing ash is a great firewood. If forest grown, it splits really well. Not a bad guess, but I'm a civil engineer and computer programmer. I do love to teach. I hope all the removals go well for you!
good vids mate
great videos I was wondering if there is a formula that could roughly work out the amount of movement produced at the top of a tree by wedging at the base of the tree?
Thanks Alex.
For almost two months, UA-cam was hiding comments from me. I finally discovered that last weekend and began responding to them. Yours "required" the lengthiest response I have yet attempted. I was a few lines shy of sending it when it suddenly converted into a tiny electromagnetic puff of heat. Needless to say, I was quietly, but highly, pissed off. It gave me an aversion to trying again until tonight. If this attempt also disappears into the ether, you will hear the explosion and have no idea what that was.
In answer to your question, I am practically certain there is no such formula. However, a mathematically true, but physically flawed, formula can be worked out. First, we have to define some variables.
Let Ht be the height of the tree in feet.
Let Kw be the width of the kerf for your back cut. (Assume 3/8")
Let Ww be the width of your wedge measured in inches, right at the point where it enters the wood of the trunk.
Let Ma be the moment arm, measured from that same point, perpendicularly to the effective center of the hinge you have cut.
Let Tm be what you want to find, the feet of movement at the top of the tree.
Given those variables, the theoretical formula would be:
Tm = Ht x ((Ww - Kw)/Ma)
As an example, say you have a 70 foot tall pine tree (Ht = 70)
Say the distance from where you wedge enters the trunk to your hinge is 7" (Ma = 7)
Say your wedge is 1" thick at the end, but you have only driven it in to where it is 3/4" thick. (Ww = 3/4). Remember that 3/8" of that is "wasted" just replacing the wood you removed making your kerf.
Applying the formula, we get:
Tm = 70' x ((3/4 - 3/8)/7) or
Tm = 10' x 3/8 = 3'-9" Unfortunately, this ignores some physical issues. The most important one is that wood is not inelastic.
Prior to your cutting and wedging, the weight of the tree was supported by the entire area of the cross section. Due to your vicious attack, that weight is now supported only by the hinge and your wedge. Given that you are needing to wedge it, the pressure that the wedge is exerting on the wood is quite a bit higher then the pressure on the hinge wood. As a result, the wood at the hinge compresses somewhat and the lift is reduced. The movement at the top might be reduced by half.
You can, however, improve the situation by driving additional wedges. With three wedges, the stress on the wood at each will be reduced to about a third of what the one was feeling and you will get closer to your theoretical lift.
The compressibility of the wood will vary significantly with species, density, moisture content, and any rot.
thank you very much for your answer it is a great help. when felling in tight situations I like to roughly work out all possibilities by measuring the tree size and I always wondered if it was possible to to figure out how much lift I would have to produce on a back leaning tree to tip the balance.
Alex Beedie Ah! So it was not just idle curiosity. ; )
Good info. but terrible sound quality
Yeah. Sorry 'bout that. I won't compete with a stream again. Also, it turned out that my camera was set to Autofocus. Works fine for still photography, but adds a bunch of noise if you're taking video.
Nice looking brook; quite annoying wile trying to listen
Definitely agree. I had no idea the microphone would pick up the noise so well. Won't do that again. Unfortunately, it was only one of several sound issues I've had to work on on the videos.