Why 1/3 notch depth?

[ATH]

......

Too close to one edge or the other, and the holding wood/ hinge may split out of the tree rather than bend.
....

I don't think "too close" to the front will cause a split or really cause any dangers in most circumstances. it is just harder to get past center of gravity. It is not uncommon when logging to just about cut straight down root flares not getting into the "cylinder" of the log and having the hinge that meets the 80% guideline (if the 'right' tree - obviously not every tree).

 

[ATH]

Don't forget about the fact that sapwood holds different than heartwood. 1/3rd depth and you'll generally be employing a greater percentage of sapwood fibers in the hinge. 80% depth and you're likely to only have sapwood on the outer most edges of the hinge. I like the 1/3rd depth general rule because it gives room to work with wedges or correct the cut if needed. I have also gone deep on a notch to manipulate the center of gravity. The "rules" are general guidelines. We can adapt them based on each individual tree/scenario.

Agreed on all points...but just pointing out that if you are looking at heartwood:sapwood that would be the same if you were 1/3 o the way in or 2/3 of the way in (1/3 away from the back). More sapwood at 80% of total depth. I am NOT saying that means it is a good idea to cut in that deep...just the ratio is the same

 

[Keeth]

What is the “WHY” behind the 1/3 depth of a notch? Thanks

It is an older guideline that was abandoned years ago. As several have said, the latest guidelines favor 80% of diameter hinge width and 10% hinge thickness. On a perfect cylinder cross section (i.e. a circle), 80% is only 1/5 of the way in.

I remember reading/hearing the move to an 80% hinge was to include more of the stronger and flexible outer fibers. In principle, hinge is stronger and you’ll have a longer lever from the back with wedges.

 

[Daniel]

Many of the answers here are partially correct, but many also are repeating commonly held fallacies, and other contributors simply don't know what they're talking about. The total conversation makes it clear that there is still a large gap in knowledge within the industry, though not nearly as bad as it was pre-internet.

To be clear the 1/3 "guideline" refers to the depth of the notch

the 80% guideline refers to the total length of the hinge relative to the diameter at the cut, so if the tree is 50" in diameter at the cut, the hinge should be 40" in length, no matter how deep a notch is required.

One detail that I have never heard mentioned when it comes to the 80% recommendation is: should that 80% (40" in the above example) length be measured at the front of the hinge or the back of the hinge? They will be significantly different. Since that distinction has never been addressed, perhaps we should just say that the 40" should be the average length or middle of the hinge. Either way, whether the one-third rule or the 80% rule, the question remains "WHY?"

The 10% hinge width is another guideline that is not well understood. I'd guess that not one instructor of 50 in the world could accurately address all the factors involved in those two guidelines. Since even the "experts" lack a complete understanding, it's just easier to say "do it like this" without an explanation. Thus in 2022 the question is asked and the above answers are still incomplete. It's actually phenomenal that with such a fundamental skill this question has been so rarely addressed in all these years. And there are so many of the unlearned masses that have never even bothered to think about "the why", yet they often hold vehement beliefs about "the rules", and get all righteous and indignant with anyone who might suggest or demonstrate otherwise. Sounds a lot like mass formation psychosis to me. An entire industry where everyone, for decades, has just done it the way they were taught, without ever questioning why.

It is understandable that there is going to be inertia within the educational institutions in the industry. They are not going to advocate for changing "The rules" because they don't want to assume responsibility for situations where a little knowledge becomes dangerous. There are far too many factors that make a complete teaching on the subject very complex. Few if any of the "instructors" have this complete understanding, to begin with. But even if they did, it would be very difficult to accurately convey that knowledge, especially to newbies, because there are just too many factors involved. Thus you 're not going to learn much about advanced falling techniques from professional educators. As such, Youtube has become a major factor in pushing the boundaries of acceptable techniques.

Unfortunately, it's easy to pass on bad habits or show advanced techniques that could be extremely dangerous when improperly applied on YouTube. One example would be the unnecessary tip tying shown by August and Reg. While they may appear to do it safely, Human (Corey) almost got himself killed by improper application of the technique... literally 6" from death. He claimed to be a big Hunicke fan, and admitted to cutting Humboldts regularly because that's what he saw the west coast guys doing. Watching him come that close to death is a very sobering reminder of just how serious the consequences of incomplete understanding can be in this business. He had no idea that the piece he was about to cut could helicopter around the back of the tree and smash his skull in.

When falling or taking tops there are going to be many factors that can make a difference in how deep a notch to cut. Just to name a few:
1) how big is your bar relative to the cut?
2) are you falling with wedges or pulling with ropes, and if using ropes how much pull do you have in the system, how high are they set?
3) How much side lean are you fighting?
4) Does the tree or top have front lean, no lean, or a slight back lean etc?
5) what degree of accuracy is needed?
6) how prone is the species, given the lean of the tree, to barber chair?
7) what are the obstacles involved should you lose the tree to side lean?
8) how much of a hurry are you in?
9) are you trying to jump the top?

And the list could go on....

And for those that like to think about such things, here's another question for YOU...

WHEN DON'T YOU NEED A HINGE?

 

[Daniel]

@Tony is not going to be teaching this type of "hinge" anytime soon.

It would be good to ask @Mark Chisholm what notch recommendations he teaches vs what he uses and why... as said above what can be taught is often going to be quite different from what is actually done.

 

[Chris Schultz]

@Tony is not going to be teaching this type of "hinge" anytime soon.

It would be good to ask @Mark Chisholm what notch recommendations he teaches vs what he uses and why... as said above what can be taught is often going to be quite different from what is actually done.

What is the relevance of this?

 

[Phil]

Many of the answers here are partially correct, but many also are repeating commonly held fallacies, and other contributors simply don't know what they're talking about. The total conversation makes it clear that there is still a large gap in knowledge within the industry, though not nearly as bad as it was pre-internet.

To be clear the 1/3 "guideline" refers to the depth of the notch

the 80% guideline refers to the total length of the hinge relative to the diameter at the cut, so if the tree is 50" in diameter at the cut, the hinge should be 40" in length, no matter how deep a notch is required.

One detail that I have never heard mentioned when it comes to the 80% recommendation is: should that 80% (40" in the above example) length be measured at the front of the hinge or the back of the hinge? They will be significantly different. Since that distinction has never been addressed, perhaps we should just say that the 40" should be the average length or middle of the hinge. Either way, whether the one-third rule or the 80% rule, the question remains "WHY?"

The 10% hinge width is another guideline that is not well understood. I'd guess that not one instructor of 50 in the world could accurately address all the factors involved in those two guidelines. Since even the "experts" lack a complete understanding, it's just easier to say "do it like this" without an explanation. Thus in 2022 the question is asked and the above answers are still incomplete. It's actually phenomenal that with such a fundamental skill this question has been so rarely addressed in all these years. And there are so many of the unlearned masses that have never even bothered to think about "the why", yet they often hold vehement beliefs about "the rules", and get all righteous and indignant with anyone who might suggest or demonstrate otherwise. Sounds a lot like mass formation psychosis to me. An entire industry where everyone, for decades, has just done it the way they were taught, without ever questioning why.

It is understandable that there is going to be inertia within the educational institutions in the industry. They are not going to advocate for changing "The rules" because they don't want to assume responsibility for situations where a little knowledge becomes dangerous. There are far too many factors that make a complete teaching on the subject very complex. Few if any of the "instructors" have this complete understanding, to begin with. But even if they did, it would be very difficult to accurately convey that knowledge, especially to newbies, because there are just too many factors involved. Thus you 're not going to learn much about advanced falling techniques from professional educators. As such, Youtube has become a major factor in pushing the boundaries of acceptable techniques.

Unfortunately, it's easy to pass on bad habits or show advanced techniques that could be extremely dangerous when improperly applied on YouTube. One example would be the unnecessary tip tying shown by August and Reg. While they may appear to do it safely, Human (Corey) almost got himself killed by improper application of the technique... literally 6" from death. He claimed to be a big Hunicke fan, and admitted to cutting Humboldts regularly because that's what he saw the west coast guys doing. Watching him come that close to death is a very sobering reminder of just how serious the consequences of incomplete understanding can be in this business. He had no idea that the piece he was about to cut could helicopter around the back of the tree and smash his skull in.

When falling or taking tops there are going to be many factors that can make a difference in how deep a notch to cut. Just to name a few:
1) how big is your bar relative to the cut?
2) are you falling with wedges or pulling with ropes, and if using ropes how much pull do you have in the system, how high are they set?
3) How much side lean are you fighting?
4) Does the tree or top have front lean, no lean, or a slight back lean etc?
5) what degree of accuracy is needed?
6) how prone is the species, given the lean of the tree, to barber chair?
7) what are the obstacles involved should you lose the tree to side lean?
8) how much of a hurry are you in?
9) are you trying to jump the top?

And the list could go on....

And for those that like to think about such things, here's another question for YOU...

WHEN DON'T YOU NEED A HINGE?

So many words used and little, to nothing of value was said.

 

[Daniel]

Don't forget about the fact that sapwood holds different than heartwood. 1/3rd depth and you'll generally be employing a greater percentage of sapwood fibers in the hinge. 80% depth and you're likely to only have sapwood on the outer most edges of the hinge. I like the 1/3rd depth general rule because it gives room to work with wedges or correct the cut if needed. I have also gone deep on a notch to manipulate the center of gravity. The "rules" are general guidelines. We can adapt them based on each individual tree/scenario.

You're one of the people I was referring to as spreading fallacies.... though it's commonly thought in the industry that sapwood holds better than heartwood, there is zero evidence to suggest any consistent variability in the holding ability of the fibers themselves. THE ONLY REASON you get more control out of holding wood at the sides of the hinge is because it is better positioned to have more leverage against side lean... of course internal decay can turn the holding ability of heartwood to about nothing, but plenty of heartwood holds quite well, as good or better than sapwood.

You should be taking notes

 

[Phil]

You're one of the people I was referring to as spreading fallacies.... though it's commonly thought in the industry that sapwood holds better than heartwood, there is zero evidence to suggest any consistent variability in the holding ability of the fibers themselves. THE ONLY REASON you get more control out of holding wood at the sides of the hinge is because it is better positioned to have more leverage against side lean... of course internal decay can turn the holding ability of heartwood to about nothing, but plenty of heartwood holds quite well, as good or better than sapwood.

You should be taking notes

Me think thou doth protest too much

 

[Tom Dunlap]

After 29 replies and line after line of discussion I think it might be a good time to distill out the various answers to 'Why?'

Make the 'answer' be a bullet point. Just a few words.

Set the bickering aside and make your point concisely. If you know, then answer, don't just berate the rest of the people who are commenting.

At one keynote talk at Expo Dr. Shigo was asked a 'Why...?' question. His reply was something to the effect, ' Why...?' is a religious question and I'm not doing religion today.'

 

[Daniel]

After 29 replies and line after line of discussion I think it might be a good time to distill out the various answers to 'Why?'

Make the 'answer' be a bullet point. Just a few words.

Set the bickering aside and make your point concisely. If you know, then answer, don't just berate the rest of the people who are commenting.

At one keynote talk at Expo Dr. Shigo was asked a 'Why...?' question. His reply was something to the effect, ' Why...?' is a religious question and I'm not doing religion today.'

Shigo, proclaimed "the father of modern arboriculture", both pushed arboriculture to a new level, and has since become an albatross around the industry's neck.... The reverence for his teachings in the industry has held back the development of pruning techniques that should have long since evolved PAST his teachings. He was extremely unrealistic in his expectations. His teaching to strive for the perfect target cut on every cut, even when the target is unclear, was particularly harmful to all the trees that were unnecessarily butchered as a consequence of the many resulting cuts that violated the BPZ. He suggested that if we weren't sure where the target was we should make the target cut to the best of our ability then go back a year later and examine the formation of woundwood to see if we got it right is completely out of touch with the realities of how tree work in the field happens and reflects his ivory tower mentality. Those that repeat such an impractical directive in their teachings are stuck in the legacy of that ivory tower mentality. It's ridiculous and if I AM the only one saying the emperor has no clothes then so be it.

Shigo may have suggested that asking the "Why" of how trees compartmentalize was like asking why is the sky blue, but your analogy here is misplaced. Knowing the why: that is the principles of physics that govern the function of holding wood in tree falling, is CRUCIAL, extremely valuable, and practical knowledge. If one is to learn how to throw everything to his advantage in tree falling and push the limits to know what can and cannot be done, HE NEEDS TO KNOW THE WHY. Knowing why in rigging is crucial as well. Those that don't know the why are confined to working within a very limited box of conventional teachings. That would be the vast majority of tree workers.

I could write a chapter or entire article on the subject of how deep the notch should be. If I do, it won't be for treebuzz. Disrespect from the posters here does not inspire generosity. If you or Mark know the answer then feel free to chime in. It's your show. Lead by example if you can. If you can't, don't expect others to do it for you.

Many years ago I was showing a young and talented tree climber the technique of cutting a deep notch to "cut a lean into the tree". I wasn't much of a tree, maybe 15" DBH. The cut was set at 2/3 depth and worked beautifully. A week later another highly talented and experienced climber was on the job site. He looked at the stump, and proudly proclaimed, that whoever made that cut didn't have a clue what he was doing. I kept my mouth shut. When I told the young climber what happened, we both just laughed.

 

[evo]

Here we go…. Again…. And again…

one can point out many unsafe work practices in @Daniel ‘s videos. Hubris is one of the many….

Now to the original post and point. Yes a 1/3 notch is safest for most fair standing generic trees, yes 80% hinge give or take is safest for most generic trees, and yes sapwood has better holding in most generic trees.

So for a blanket guideline yes one SHOULD follow these guidelines, but they SHALL consider alternatives to these guidelines as ALL trees are not the same in ALL circumstances.

 

[Daniel]

Here we go…. Again…. And again…

one can point out many unsafe work practices in @Daniel ‘s videos. Hubris is one of the many….

Now to the original post and point. Yes a 1/3 notch is safest for most fair standing generic trees, yes 80% hinge give or take is safest for most generic trees, and yes sapwood has better holding in most generic trees.

So for a blanket guideline yes one SHOULD follow these guidelines, but they SHALL consider alternatives to these guidelines as ALL trees are not the same in ALL circumstances.

once again you throw mud.. Is that the best you got? Cause it's weak. While you know more by far than most here, your input on the subject of notch depth is also weak. And your suggestion that sapwood is stronger than heartwood is simply wrong. So if me saying sorry you got that wrong evo is hubris, then I'll cop to it..

if you can point out unsafe practices in my writings or videos then please do and we can have an intelligent discussion that will surely offer some valuable teachings to others here. If my practices seem unsafe to you, it's because they are unsafe to those that don't understand them. That doesn't make them unsafe for me. Because I know the WHY. I know what works and how far to push the limits.

So please get specific. I AM happy to respond to any of your specific criticisms. Man up if you can! If you can't, then just keep throwing mud and here we go again!

 

[Tom Dunlap]

The thread has drifted some.

More lines and more talk but no answers.

All these lines about Shigo should be put into a different thread. The topic here is hinge wood not target pruning.

There seems to be an almost religious stridency about each face cut. This is the reason I included what I did.

 

[Daniel]

Here are some deep notches for you @evo

 

[Daniel]

The thread has drifted some.

More lines and more talk but no answers.

All these lines about Shigo should be put into a different thread. The topic here is hinge wood not target pruning.

There seems to be an almost religious stridency about each face cut. This is the reason I included what I did.

Threads drift... they always have and always will. What you refer to as "religious stridency" seems appropriate here. I learned a new term related to how brainwashed people are about the pandemic and the vaxxines. MASS FORMATION PSYCHOSIS... that seems another way of putting it. People that don;t know what they are talking about get all full of "religious stridency" when it comes to notches and vaxxines... HAHA Tom.. there I go drifting again!!!

 

[evo]

once again you throw mud.. Is that the best you got? Cause it's weak. While you know more by far than most here, your input on the subject of notch depth is also weak. And your suggestion that sapwood is stronger than heartwood is simply wrong. So if me saying sorry you got that wrong evo is hubris, then I'll cop to it..

if you can point out unsafe practices in my writings or videos then please do and we can have an intelligent discussion that will surely offer some valuable teachings to others here. If my practices seem unsafe to you, it's because they are unsafe to those that don't understand them. That doesn't make them unsafe for me. Because I know the WHY. I know what works and how far to push the limits.

So please get specific. I AM happy to respond to any of your specific criticisms. Man up if you can! If you can't, then just keep throwing mud and here we go again!

I don’t need to waste my breath nor time. I’ll do it my way, and have my observations.. I’ve never advised that I know it all, and that I’m always right.
I have better things to do than argue sapwood hinge strength

 

[evo]

Here are some deep notches for you @evo

Wow, just wow.. would you like me to wear lip stick while I get on my knees and inflate your ego.. I know you need all the help you can get sweet cheeks.

 

[Daniel]

I don’t need to waste my breath nor time. I’ll do it my way, and have my observations.. I’ve never advised that I know it all, and that I’m always right.
I have better things to do than argue sapwood hinge strength

right.. more BS... no substance...

You don't mind throwing mud but don't have the time or inclination to back up your personal attacks..

here we go again.

 

[evo]

right.. more BS... no substance... here we go again

There is no conversation with you. Why should I provide you with ‘substance’? Read my words and consider them…. Until you do and communicate like a human I have no time..
it’s not unlike how we communicate with your private message to me. The two faced push pull, is getting old.