Hinge Forensics

[TheTreeSpyder]

i think that on a conventrional notch of size, 2" catch lip against tree coming back is recomended, though i think tree steers better coming straight into apex of FaceCut; so i go for that but with a wide face 'birds beak'(?) FaceCut.

i always inspect the FaceCut for rot and miss cuts (unintentional kerf dutchmans), never assume anything; sometimes trace a 'chalk line' to walk with saw just so deep around the back perfectly connecting corners of FaceCuts; so when i'm doing it for real, i know i'm square.

i bet the ground man was pulling for all they were worth; they had to pull up the ramp some, and break that far fiber towards building. The fiber is in a very leveraged position to fight ground control, pit crew; suddenly it let lose, with hardly any hinge to control, everyone glad when it was done. Cutter stressed cuz they were in there sweating in the kill zone; in a tight box with no where to go, knowing enough fiber was gone that thing should be off him; not realizing remaining fiber was in leveraged position to fight the crew pulling!

in general i think a forward pull from face is best, to leverage a stronger hinge and let that take care of SideLean; rather than fighting SideLean with line, let leveraged fiber do that for you in response. But in a case like this of compromise by saw or rot etc. of the fibers, pulling to the opposite side to steer i think is best as the fibers leveraged support is compromised; IMLHO.

Orrrrrrrrrrrrrrrr some'tin like that!
:alien:

 

[SilverBlue]

Excellent observations Brian and Ken, it was sloppy workmanship that made the job difficult, the rope man did have to work harder and there was no control at all.
Yellowdog, if the back cut was higher and the angles were acceptable this tree would have been so simple. Instead it almost turned into a disaster.

 

[Yellowdog]

Truly and awesome diagram Spyder! I think your observations are very helpful and I for one, am greatful. It makes great sense to analyze what you did and why you did it while things are fresh in the mind.
You are very close to the way things went down! I don't remember if there was a line pull or not. The tree had quite a lean away from house. This house was from 1880's and I imagine someone dropped a pecan too close to the house!

I guess I was lucky to make it out of that one. Thought I had it all planned out.

 

[Kneejerk Bombas]

SB, which was the notch side, the bottom? If so there was a huge toe nail (unintended Kerf dutchman), and he cut through the hinge.
I disagree that the backcut was too low, if anything it was too high.
Unless the top of the picture is the notch side, then there are all different problems!

 

[Yellowdog]

Originally posted by SilverBlue
Excellent observations Brian and Ken, it was sloppy workmanship that made the job difficult, the rope man did have to work harder and there was no control at all.
Yellowdog, if the back cut was higher and the angles were acceptable this tree would have been so simple. Instead it almost turned into a disaster.

I think you hit the nail on the head...

 

[Yellowdog]

Originally posted by Mike Maas
SB, which was the notch side, the bottom?

The notch was out of the left of the picture. See the pic where the tree fell.

 

[Kneejerk Bombas]

Sorry YD, I was talking about SB's Birch stump.

 

[Yellowdog]

Sorry too, Mike.

I didn't post the pic where that tree went until after..

 

[SilverBlue]

Mike, the notch is on the bottom and angles down to the left.

 

[Hemlock]

Great post! Stump always tells the tale. One thing that would be very helpful for me would be if the stump were cleaned up better so that I could see the chain marks as well. It is very hard to judge what happened through the limited eye of a camera and kerfs and hingewood only tells part of what happened. Alot can be learned by studying the small grooves of the chain and trying to figure out how the sawyer worked the saw through the cuts leading up to the end result. Fun topic and good feedback.

 

[TheTreeSpyder]

i got confused too Mike, thread changed as i was drawing; reply window shows words but not pix; so didn't even know SB had posted one!

i think Mike has made a real good point, and if ya don't see it or don't think it matters; it can get ya!

The un-intentional Kerf DutchMan step will close early and push to the opposite side.

The RopeMan was prolly working against themselves as the tree set forward just enough to close kerf; then his leveraged pressure would use the closed face to push against him.

DutchMan's are typically the most dangerous adjustment to travel, so much so that they are banned etc. in some places. They are very powerful, capable of invoking all of the weight, leverage and speed of a massive tree at peak and using it. Especially, unintentionally this can be dangerous ground.

In branchings, tops etc. of less leverage and weight we may be able to use such a force judiciously; but here it is unintentionally and incorrectly applied if i read it right.

This comes down to doing the simple things correctly, making the FaceCuts precisely meet; like crafting a fine machine to pivot tons of force, make it right once!

 

[TheTreeSpyder]

The model i envision for tree cutting carries from felling to bucking, freefalling, rigging is all the same. Scheduling leverage to allow my path of choice; while also scheduling leverage to be fortified against the pull away from target (to the side).

The basic structure that being in the hinge is narrow (for less leverage agianst movement) to the desired direction of fall; while maintaining fortified positions of leverage against the lean away from desired fall, with a long stretching hinge.

Increasing that; by putting more fiber in the levrage against lean area; yet reducing still the leverage against desired path; by simply slanting the BackCut for a tapered hinge shape. For i see the support as a balance across the compressed part of the hinge in the "Hinge Forensics" pix. The support are the long stretched fibers opposite the compressed fiber pivot. Quite simply, the farther apart you can get these 2, the more leverage of support, for this balance; just as the farther the C.o.B. is from the same compressed pivot, increases leveraged load.

 

[TheTreeSpyder]

i was asked to come see this today.

i've made all kinds of mistakes, so this isn't about nailing anyone etc.

i think this education is serious; especially this particular one; on how not to get smooooooooshed!

 

[wiley_p]

Without seeing the tree I cant say for sure but, if he was using say a 24" bar there wasnt enough lentgh for a doulble cut so I would have bored holding wood in the middle out from the face, that would have left 8"+ on each corner, still retaining guidance to the lay. This is all assuming the favor and face were properly sized up.

 

[John Ellison]

This must be the work of an arborist, loggers can't make that complicated multi-directional face. Its about a 16'' oak, whats bad is the power line about 20' behind it.

John

 

[TheTreeSpyder]

Church Voluntears

 

[TheTreeSpyder]

More scary hinging just in time for Halloween. Kinda home owner cuts from the hurricanes.

The 2nd pictures show a tree fallen the wrong way; the 1st a tree fallen without a face. i think faceless falling can lead to a dreaded barber chair.

i think of a barberchair as happening because of the leveraged force of a tree and it's equal and opposite reaction confronting each other. Neither the force of the tree, nor it's mirror winning; giving a split decision that shears the spar apart with these awesome forces.

To not allow this to happen; i think the relief of the face + relief of the backcut has to lessen the mirror force and allow the fall.

The siezing pressure buildup that can cause a barberchair can be caused by no face, dutched face (neither giving enough relief to face, causing push back) or too slow a back cut under such shearing forces as a large tree. All 3 situations allowing a force buildup.

That force is set into test the soundness of the spar; which can shear up it's center in this split decision of matched forces at some point.

Or something like that;
no place i wanna be!
:alien:

 

[jason j ladue]

this is exactly the kind of subject matter what we need to get back to on this site. this thread is un freakin believable. everybody on this site should read and digest this entire thread. super high quality education. like a college course intensity. massive ammounts of knowledge here... thanks kc, maas, silver blue (you're missed; ellison too). thanks guys. my hat's off to you.

 

[ozy365]

I read most of the thread, but I am still unclear on what a dutchman is in this context. Could someone give me a definition? I'll bet this will read like a new thread to me with the lesson in vocabulary.

 

[clearance]

A dutchman is the term for when the undercut is sawn in such a manner that the two cuts it takes to make the undercut do not line up, by accident or intention. Specifically this means when the first cut (the one at 90 degrees to the stem) extends past the one that is on a 30 to 45 degree angle. When the tree falls, it stops momentarily on this flat spot, this can cause the tree to chair or fall in the wrong direction. It can also be used on purpose to swing or throw a tree, by putting in a dutchman and then cutting off the holding wood on the same side as the dutchman, proffesional fallers can make the tree fall into the preffered lay. This practice is prohibited by our workers compensation board, I don't use it myself, but men that fall big wood do what they want because they know how to make it work.