takedown

[mquinn]

geofore - the link to the pics:

http://www.missouri.edu/~quinnl/trees/takedown/takedown.html

i can put a link to this thread on the commercial forum if you think there are more helpful comments that would weigh in.

..........

i should have credited the input i posted earlier from one of the guys i emailed privately: that was from ox. i'll go back and edit that posting to add his name.

thanks again to everyone. i'll take all this to the arbo who's dropping the second tree tomorrow.

thank you so much.

 

[mquinn]

i had a chance to talk to the arborist a bit this morning, and he was making many of the same points that you all have made here. he said that his brake line men were not understanding what they needed to do and were holding the tree back from falling while the guys on the other end were pulling to get it to fall. he felt that, in combination with his cut, caused the spin, and he wants to try the same rigging again with the second tree. but he thinks the trees on either side of it might not line up well enough, so he might not be able to.

i gave him a printout of all your comments, and i suppose it's possible they might change his mind. (thanks again. i personally didn't completely understand all of your comments, but i'm not taking down the tree. i'll ask the arbo about the things i didn't understand later.) we'll see when he gets to the felling process how he decides to do it and what happens. i'll be taking pictures of that, as well.

of course, the arbo and i both think the decision to not drop the trees in the lawn is absurd. lawn repair is surely cheaper than arbo time spent rigging and lowering. (and they always ruin the lawn by over-irrigation anyway!) oh well. politics. (and nice practice for the arbo.)

geofore suggests the commercial forum is the best place for this discussion because it gets more traffic and this is a good learning thread. i'll post a link to it on that forum then.
muchas gracias.

 

[Stumper]

mquinn, One thing that I alluded to but did not explain in one of my earlier posts.-Rear brake line rigging is complex and is potentially dangerous so I have largely abandoned it (as you said lawn repair is cheap). When I was playing with it I used 2 lines.
By arranging two brake lines at diverging angles it is possible to reduce a tendency to spin off even if the hinge fails(the possibility of the spar kicking back/riding over the stump is still there though!) What I would suggest is this > where the apex is the spar and its intended direction of fall and the two legs of the "arrow"or V are control lines.Spread those lines further than the illustration if possible. If both lines are kept taut and paid out smoothly and equally the spar is prevented from falling sideways as readily as it will with a single line (unless the butt starts sliding). This can still fail but it is better than a single line which goes slack sooner as the sideways pivoting proceeds.
My personal advice is to abandon rear braking and just fix the divots in the lawn but if he is going to do it--- balance the side pressures with two lines!:angel:

P.S. He still needs a taut pull line in front to keep this thing under control! Shoot! Beg him to abandon the rear braking-it gets too screwey!

 

[mquinn]

stumper, thanks. i think he won't have the possibility of doing it that way, as there isn't another good place to hang the other brake line (building on one side, 'precious lawn' - as we call it - on the other). what i will do, however, is provide him this post of yours in printout so he can take it to the bosses for buttressing his argument that he needs to be permitted to drop the tree on the lawn.

maybe he could chunk it all the way down. ?? seems like he told me why he couldn't do that, but i don't remember what he said.

 

[TheTreeSpyder]

Very good discussion, very good test of theories and images used personally while assessing these mechanics. Think it would make a dynamic chat..........

i'd like to say that i'm glad noone was hurt by the tree landing 90* from target and/or ressultant forces from this tension on spar, or line snapping, branches over someone's head breaking free on that control line behind the spar going to other tree. Or, spar not moving quick enough and poor cutter taking out more hinge.....

i think that this would turn, cuz it to me is a self tightening rig, favouring the higher pressure side for spin to. For exactly (oooops here goes, never thought i'd say this.......) for the reasons that JP says, if the control line pull is not center, it will pull off center. It will create this pull from the weight, speed, and hitched length of the spar- here enormously scheduled forces.

To counter that spin (best is to realize what ya got and not resisti it too much)a kerf dutchman or block/step dutchman ( a dutchman being an early interuption in face to cause pushing off, either of these dutchys would push off away from the line pull is put on the same side as it) can throw/punch away from this pull on that same side of the face, as too tapered hinge pulls to the other side (away from twist) can help correct the balance of pulls to target; as well; as fibre in that extreme opposite to side line pressure, position presents the most leveraged opposition to twist to the opposite side. Taking Dutchmnan push (which takes speed...), and taapered hinge pull, you might be able to balance that force with offside line pull, if line is given enough 'finesse' (proper slack at proper time); but chances are probably against. Dutch face interuptions and tapered hinge are both passive force (though diagonal to each other)strategies, that use some of the available force; but you have to throw that force into the dutchman. Each force will only work as long as it is tensioned on arc of hinge, hinge is logically the best to fight that full arc, then adding more strategies, IMLHO.

This would be synonomous to felling thru trees pushing the same way from the front that line is pulling from the back( or simiraiily dangerous vine pulls), i think the hinge taper will fight either longer on the arc of hinging than other strategies. Making it in my mind best for especially interuptions (tree branches to side front, line pull from opposite side rear being same analysis as direction and constantcy once spar is committed is same, only varied in force of each.)

Another balancing strategy (to target, against line's offside pull) would be a block on back side of the spar, with balanced angles of rear, low pull from the legs of line, one anchored, one friction device, for 2/1 of balanced pull on spar. But paying out line fast enough as to not bind or pull too much is already a problem, this would increase with less load on friction device. i guess that would be the self equalizing version of comradski Stumper's idea, just set at equal rear angles.

i think the pull line, pulls to target, and control line should allow freedom of movement before 1:30 to force stronger hinge, then start lending support definitely by 2:30; if you care to take that danger(using rear line). If during this phase (before 1:30-2:30)the control line pulls against the pull line, the hinge will form weaker, you need the control line barely checking the pull, and the hinge taking the stress to make hinge strong for rest of journey on arc of delivery. After that

If this was moving up on same axis, or down from 3 to 6:00, i would say it invokes hinge pocket pressure to help, but here the pressure comes off; not on, not because it isn't available, but the resistance to it is lower, to give effect.

Alternatively,if needing to drop across the drive (i think that 'porcelan' is more fragile than sand..., grass can take any strategy drive can; sounds like insurance liabilty deal).

So i would choose lower force, deflecting delivery to forgiving ground in compounding factors to my favour. To stack the level of help, higher than that of the test, while lowering the pressure of the challenger's force.

i would try to get Center of Balance of spar to reach across the road, and provide a 'rock pile' of laarge logs to make a pivot (to keep stump end high) and carry stump end away from tree as all falling force is sliding forward on roch pile.....

And/or 3' high tightly packed matresses of brush or rimless tires etc., for (anything that crushes dissipates force) on drive. No, log, no half-azz wimpy piles, real purposefull mattress to scale of real wood!

And/or logs on grass (not on root, that could push hole in drive from underneath if hit right!) to bridge spar across drive, on stout logs on either side, and spread out force to lawn.

And/or mechanical 'fuse' bridges on lawn. =2parallel logs (to each other and spar's lay) with 3rd log bridged across, facecut up, partial backcut from bottom. Hit facecut with spar. If it takes 1500# to break it, that is 1500# subtracted from the falling force. If there are 4 sets broken, that removes a matching 3 tons from the force of the spar.

And/or let green branches stay high, form own 'matress', perhaps go up and mechaniclaly fuse to make sure and not dig in lawn, use their leverage of pull to induce stronger hinge......

And/or Delivering to the side of pull and not directly to lean, forms a fight, any of which force the tree employs in, reducing the finite amount of force delivered. So lay to the side, as not to feed straight into the pull of that ol'mutha gravity, a part of force is direction.

In fact, IMLHO, it is the first part of force, to commit which way the Mass x Speed is to be placed. So if a machine has to fight an imbalance, it must do so constantly and use up force that could be utilized elsewhere.

i too beleive in wide hinges, for when the faces meet, game over; the machine must decide wether to shear, sieze or break.

Definitely i would draw down the spar slowly, with high leverage powered by 3 men on 3-5/1 or GRCS and slow backcut to wide face. i'd have line guided over laying in V trench at top tied to back side, for highest leveraged position, and straghtest pull.

In this way the hinge is forced stronger, total drop is reduced, as well as speed; all at the same time; these reductions scheduled into sideways to lean onto forgiving aforementioned 'structures' can add up to supports needed, with less force to begin with; withoout that higher risk procedure{DAN GER!!}. IMLHO.

This is like the self tightening rigs i use on limbs. It is also with rope fibre, what i try to explain to do with slanted hinge using wood fibre at base, rather than rope fibre high. Both are passively powered, fibred restriction, that self tightens and controls by being placed on the highest leveraged position to be self powered by the motion (180* from), and that power is placed at a high leverage position on the load. The farther the arc of the hitchpoint goes from rear support (arc) the more leveraged tightening too. In these examinations, length just becomes leveraged positions for support, pivot and C.o.B.

Or Something like that!


:alien:

 

[John Paul Sanborn]

Just get a buncha old tires and fell the stick onto them.

Use a wide face, about even with the pile of rubber so that the hinge does not fail til it is on the ground.

Maybe but tie the log to the stump before making the backcut so it is less likely to jump away, off the pile.

So he uses the argument with the honchos, either we pay for the repair of the turf, or pay for some junk tires to cushion the fall onto the concrete.

 

[mquinn]

no, no, no...the really messed up thing is that the cost of all of this deal, turf and/or tree is coming from the same budget. !! so either we pay for one (or maybe two) guys to do maybe an hours' worth of turf repair or we pay an arborist and assistant plus a few brush draggers for three or four extra days' work.

i think i woke up one day a while back inside a cracked mirror.

help, mr. wizard!

oh well. my position is getting the axe. maybe next time around i'll find a cracker box on a beach somewhere and read palms.

 

[John Paul Sanborn]

Happy for the tree dudes, sad for you.

 

[mquinn]

Happy for the tree dudes, sad for you.

you mean happy for them because they get paid for more work? - they get paid very little, and they get paid the same no matter what they're doing or not doing. government work. university campus.

and the bosses are talking about cutting the arbo positions as well. let some grounds crews do hack work instead. talking about returning the landscape department to a trash collecting/mowing operation.

there was a proposal that the upper administrators (six-figure folks) take a 7% cut in salary for one year, and no one would have to get laid off. you can imagine how well that flew. they'd rather these poor guys lose their jobs and maybe their homes rather than see their own portfolios show a move backward. heaven forbid.

the place is going to gutter. state's in trouble - as are most states.

for me - i go wherever the path opens up before me. i must be done here. next chapter coming up.

 

[TheTreeSpyder]

Here is a pic i made a while back, trying to show how pulling with from the rear, is powerful. i feel in this way it is dangerous. And that is even without the lay ending up perpendicular to the aimed point. i truly feel this is very dangerous, and stated so when i made the drawing. The tree could stall, impact load nylon and spring backwards to the intended lay, slide back off stump, slide back off stump and to cutter's side etc.

The purpose of this drawing was to liken this setup to a slanted hinge pulling more to one side. We use this sideways rigging in the tree, as well as down; but not with the mass and leverage of a whole tree, for that and it's restriction (which must be finessed quickly and correctly) empower the whole system. That is some mass, speed and leverage fed into that passive system as it arcs from more ability to hang on to stump, to less ability to hang on stump. At the same time the leveraged load on hinge and line is increasing. All those factors are compounding and working against you at that angle range methinx; and on this scale, massively empowered.

My previous post was to show how to limit the force of fall with hinge pull, redirect some of that minimized energy; then recieve it with most energy absorbtion and spreading out what was left of the minimized, indirect force. And to do enough of all that with strategies in concert, to surpass the task.

Here i jsut enjoy the sorting and examinations, to see more clearly.

Or something like that,
:alien: