Why 1/3 notch depth?

[Matt hawley]

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

 

[Basswood]

I dunno but I see quite a few guys out west where the notch is more like 2/3 at the very least. Need some serious confidence in that kind of notch, but I always thought they looked like a ticking time bomb and an unnecessary risk (probably for the gram!)

 

[RyanCafferky]

The rule of thumb for a notch depth should be the hinge length you are left with. The goal should be a hinge length that is 80 percent of the diameter of the tree to give you maximum control of the tree. So 10 inch tree, 8 inch length hinge. Often you can achieve this with only a 10 percent depth notch leaving you more room to work with for bore cuts, wedges, ect.

I think a lot of things like a 45 degree notch 1/3 the way into the tree are holdovers from the days of cutting trees down with axes and crosscut saws.

 

[southsoundtree]

At 1/3 depth, you have leverage for wedges, too.



It is a throwback.




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

I super-deep cut one tree to undercut the Center of Gravity to dump it into the open. A strong wind pushed it backward. Split down from the hinge, peeling off the back of the tree. The tree fell into native brush. No consequences to that incident.

 

[dspacio]

I have wondered about the 1/2+ notch cuts, especially for dropping a top, if it helps the center of gravity find it's way toward the falling side of the hinge.

I agree with @RyanCafferky , I always heard it was about giving yourself the proper amount of hinge wood.

 

[southsoundtree]

Trees take all different widths at different percentages of depth.

80% width is a good guideline, but it isn't a rule. Think of gutted hinges and hollow trees. Regular stuff.

All things are very situationally dependent, including Very species dependent.




I don't go deep on tops personally. If you can't push it, you should be wedging it. $0.02.

Halfway depth for a very balanced top, no wind, yes.
Deeper, asking for trouble, at times.

Shifting the hinge a few inches is different that 12".

12" shift has a lot more eyeball-evaluation certainty. Generally, the initial facecut kerf may start to close a tiny bit or more with a rearward hinge on logs...confirmation that you are winning.

Be careful with very straight grained/ Barberchair prone wood if you're loading the hinge up a lot with a heavy log on a rear-placed hinge.

 

[vkoot]

I dunno but I see quite a few guys out west where the notch is more like 2/3 at the very least. Need some serious confidence in that kind of notch, but I always thought they looked like a ticking time bomb and an unnecessary risk (probably for the gram!)

Are you sure you've seen 2/3 on full trees? If I'm chunking down wood, i'll go 2/3 deep all day to help it go over if needed. I'd never go that deep on a full tree though. No room for wedges, and easier to sit back on you if its a tall tree. Where have you seen guys out west do that? Its not normal.

 

[Vicente]

I do roughly 30% for my falling cuts, when I'm doing wood I usually go 50% or more shifts the weight past the hinge so I don't have to worry about wedges in the tree and there's not so much above the cut I'm worried about it snapping off backwards.

 

[Basswood]

Are you sure you've seen 2/3 on full trees? If I'm chunking down wood, i'll go 2/3 deep all day to help it go over if needed. I'd never go that deep on a full tree though. No room for wedges, and easier to sit back on you if its a tall tree. Where have you seen guys out west do that? Its not normal.

Yeah I’ll try to find one. Definitely of big tops and wood while climbing, just saw one of a whole tree.

 

[Phil]

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.

 

[evo]

Thank you Phil, I was going to add that to the conversation. One can bore and gut out most the heartwood, the 30% leaves the most amount of sapwood (corners of the hinge) while still being effective.
I go anywhere from 20% to just over 50% when felling. Most the time it’s probably closer to 40%.. but it varies on many factors

 

[Tony]

The best reason to forgo any depth ratio like 1/3 and choose instead a hinge length ratio, like many have said, is trees are not always perfectly round. A hinge length ration compensates for this

Tony

 

[Phil]

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

Its really funny to me that you asked this question so simply and used the word, "why". I specifically phrase the flow of critical thinking choices like this when I do trainings. I think I even mentioned it in a previous post on another thread here somewhere. One should always be able to answer the question "why" when we are making our choices or evaluating decisions. Why am I going 1/3rd, why am I going 50%, why am I using a rope instead of just wedges etc etc. The big joke I always tell is sometimes the question ends up being, "why the fuck did I do that?"

 

[Tony]

Its really funny to me that you asked this question so simply and used the word, "why". I specifically phrase the flow of critical thinking choices like this when I do trainings. I think I even mentioned it in a previous post on another thread here somewhere. One should always be able to answer the question "why" when we are making our choices or evaluating decisions. Why am I going 1/3rd, why am I going 50%, why am I using a rope instead of just wedges etc etc. The big joke I always tell is sometimes the question ends up being, "why the fuck did I do that?"

Phil,

As a long time trainer, I have found the more valuable question is “why not?” Understanding “why” certainly is important as it gives validity to the “how” of a task. However, ”why” questions really, in the end, only address methods.

Asking “why not” questions, forces one into examining the principles of a matter.

Example: When a climber is cutting aloft, she/he should tie in twice. If we ask “why” The answer: if you cut one system, then another is in place to prevent a fall. Cutting system is always a possibility. Therefore, redundancy is a method. Why the redundancy? So we don’t create a greater hazard by exposing the climber to a fall.

Now as production arborists, we all know there are times, not uncommon, when tying in twice might not be the best idea.

Here is one, fairly common. T. I. P in another tree. The tree you are working is dead, dead, dead. Should the dead tree fail beneath you and you are secured to it with your lanyard….you become rigging…

Is it possible in this scenario to cut your line? Yes. But the method, redundancy violates the principle of creating a greater hazard.

So in the above scenario, the better question to ask is “why not?” If you have a valid answer for “why not“ you are addressing a principle. Here the principle is not to create a greater hazard, ie. exposure to fall.

“As to methods there may be a million and then some, but principles are few. The man who grasps principles can successfully select his own methods. The man who tries methods, ignoring principles, is sure to have trouble.”
― Harrington Emerson


Respectfuly,

Tony

 

[Vicente]

Phil,

As a long time trainer, I have found the more valuable question is “why not?” Understanding “why” certainly is important as it gives validity to the “how” of a task. However, ”why” questions really, in the end, only address methods.

Asking “why not” questions, forces one into examining the principles of a matter.

Example: When a climber is cutting aloft, she/he should tie in twice. If we ask “why” The answer: if you cut one system, then another is in place to prevent a fall. Cutting system is always a possibility. Therefore, redundancy is a method. Why the redundancy? So we don’t create a greater hazard by exposing the climber to a fall.

Now as production arborists, we all know there are times, not uncommon, when tying in twice might not be the best idea.

Here is one, fairly common. T. I. P in another tree. The tree you are working is dead, dead, dead. Should the dead tree fail beneath you and you are secured to it with your lanyard….you become rigging…

Is it possible in this scenario to cut your line? Yes. But the method, redundancy violates the principle of creating a greater hazard.

So in the above scenario, the better question to ask is “why not?” If you have a valid answer for “why not“ you are addressing a principle. Here the principle is not to create a greater hazard, ie. exposure to fall.

“As to methods there may be a million and then some, but principles are few. The man who grasps principles can successfully select his own methods. The man who tries methods, ignoring principles, is sure to have trouble.”
― Harrington Emerson


Respectfuly,

Tony

I removed a widow maker or of nasty oak on Thurs that had had a branch from another tree left in the crotch for decades I was pretty concerned about it possibly failing while I was up there so I had only my srt rope over the uphill and more solid seeming section on the tree for my cuts on the downhill side of it.

 

[Phil]

Phil,

As a long time trainer, I have found the more valuable question is “why not?” Understanding “why” certainly is important as it gives validity to the “how” of a task. However, ”why” questions really, in the end, only address methods.

Asking “why not” questions, forces one into examining the principles of a matter.

Example: When a climber is cutting aloft, she/he should tie in twice. If we ask “why” The answer: if you cut one system, then another is in place to prevent a fall. Cutting system is always a possibility. Therefore, redundancy is a method. Why the redundancy? So we don’t create a greater hazard by exposing the climber to a fall.

Now as production arborists, we all know there are times, not uncommon, when tying in twice might not be the best idea.

Here is one, fairly common. T. I. P in another tree. The tree you are working is dead, dead, dead. Should the dead tree fail beneath you and you are secured to it with your lanyard….you become rigging…

Is it possible in this scenario to cut your line? Yes. But the method, redundancy violates the principle of creating a greater hazard.

So in the above scenario, the better question to ask is “why not?” If you have a valid answer for “why not“ you are addressing a principle. Here the principle is not to create a greater hazard, ie. exposure to fall.

“As to methods there may be a million and then some, but principles are few. The man who grasps principles can successfully select his own methods. The man who tries methods, ignoring principles, is sure to have trouble.”
― Harrington Emerson


Respectfuly,

Tony

I appreciate that insight. I like the idea of asking the question both ways. Why and why not. Leads to a wider field of view/understanding and can make one think a bit harder on the principles.

 

[MasonH]

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.

August Hunicke hits the nail in one video talking about the rules of tree work. Basically saying that a lot of "rules" are in place for those who don't understand what's happening in order to prevent catastrophe. There are certainly tons of benefits to the 1/3 felling rule but, as you said, different scenarios call for different techniques.

 

[southsoundtree]

Phil,

As a long time trainer, I have found the more valuable question is “why not?” Understanding “why” certainly is important as it gives validity to the “how” of a task. However, ”why” questions really, in the end, only address methods.

Asking “why not” questions, forces one into examining the principles of a matter.

Example: When a climber is cutting aloft, she/he should tie in twice. If we ask “why” The answer: if you cut one system, then another is in place to prevent a fall. Cutting system is always a possibility. Therefore, redundancy is a method. Why the redundancy? So we don’t create a greater hazard by exposing the climber to a fall.

Now as production arborists, we all know there are times, not uncommon, when tying in twice might not be the best idea.

Here is one, fairly common. T. I. P in another tree. The tree you are working is dead, dead, dead. Should the dead tree fail beneath you and you are secured to it with your lanyard….you become rigging…

Is it possible in this scenario to cut your line? Yes. But the method, redundancy violates the principle of creating a greater hazard.

Two climb lines in the neighboring tree would be redundant, and a safer play.

Two ropes allow tying in twice without increasing risk.




Stack the odds...

 

[Vicente]

Two climb lines in the neighboring tree would be redundant, and a safer play.

Two ropes allow tying in twice without increasing risk.




Stack the odds...

I thought about it my cut was no where near my line and I was using my electric stihl so almost no chance of the saw kicking back or continuing to run if the tree I was working in fell and I took a swing.

 

[ATH]

Two climb lines in the neighboring tree would be redundant, and a safer play.

Two ropes allow tying in twice without increasing risk.




Stack the odds...

Agreed. "Why not" use 2 ropes in that situation.

"Almost no chance of cutting it" said everybody who cut their only point of tie in.