# The Hong Kong Tree Climber - Serious Accident



## derwoodii (Apr 28, 2014)

Youtube of dynamic tree head topping unload causing whip and harm to Hong kong climber


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## Sean80 (Apr 28, 2014)

ouch....


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## KenJax Tree (Apr 28, 2014)

He started getting rag dolled before that piece came loose.


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## Knobby57 (Apr 29, 2014)

Seems like a groundie didn't understand let it run . Could not see rigging well but it sure did fail. He may have taken a rigging block to the face. He also got whacked by the saw a few times. I counted a few things that would be considered wrong by our standards . Who knows over there they still make scaffold out of bamboo 


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## woodchuck357 (Apr 29, 2014)

A notch like that pushes the stem sideways. The stem whip as well as to big a chunk snapped the rope. A box notch would have popped the top off without pushing the stem sideways and it would have dropped butt first. But there probably was stuff below that required roping the top down, he just should have climbed higher before cutting.


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## RyKR (Apr 29, 2014)

So what would cause that to start whipping around before the top even fell? It would make sense to me if it was falling and the ground guy halted it, but it was moving beforehand.

Could they have pulled on the rope trying to pull it over causing the tree to start swaying?


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## derwoodii (Apr 29, 2014)

I got a collar bone in the wrong place that reminds me about tree dynamics and the mass dampening effect that lower limbs may have.
If you strip them away then drop of the tall head in wrong scenarios it can release the energy back into trunk fast and can kick sway fast and hard 

In this case some of that was going on but i suspect the limb caught a rope on the way over & down pulling over the trunk till it snapped then releasing back that energy as well...... poor sod that hurt bad being hit by a 50 foot of dynamic base ball bat not fun

example of dynamic energy with out any dampening lower limbs vid below 



some info Journal of Arboriculture 29(3): May 2003
file:///C:/Users/just%20a%20guest/Downloads/Dynamic%20loading%20of%20Trees%20(1).pdf

Tree Removal and Dismantling
In the conventional practice of removing a tree, the arborist
removes the side branches first, as he or she climbs the tree.
Once near the top, the arborist ties in to the trunk and cuts
the crown section, which falls away and pushes backward
on the trunk as it falls. This procedure can create enough
load on the trunk to cause severe and possibly dangerous
swaying. The sway motion of the bare trunk does have a
natural frequency, and the energy and forces developed in
the trunk below the arborist may be greater than the tree
would experience under natural conditions, when the side
branches are attached.
The bare trunk has a natural frequency because the
mass damping effect of the side limbs has been removed.
Without the damping of the branches, large sway motions
may occur, with associated large forces developing in the
trunk. If there are hidden defects in the trunk below the
arborist, the large forces generated may cause failure, with
dangerous consequences to the climber.
There may be alternative removal techniques that utilize
the natural energy dissipation in the tree. One idea is to
leave the side branches on the tree, climb to the top section,
and make the crown cut the first cut in the removal proces


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## woodchuck357 (Apr 29, 2014)

RyKR said:


> So what would cause that to start whipping around before the top even fell? It would make sense to me if it was falling and the ground guy halted it, but it was moving beforehand.
> Could they have pulled on the rope trying to pull it over causing the tree to start swaying?



The wide open face notch allows the top to push the stem sideways before it breaks off. As the top falls over while still attached to the stem much of the force generated by the fall is directed into the stem which is free to move in the direction away from the top. The same forces act on a stump as a tree falls but the stump is anchored so doesn't move. A pull on a tag line would counter the push of the top slightly, very slightly. The major whip was caused by the top pulling the stem in the direction of the fall then releasing that pull when the rope broke.
The safest way to work is to take smaller pieces, but a lot of folks like taking it to the limit and that means they sometimes go to far. I have to admit that I like riding a moderate whip when dropping chunks and tops. I try to keep the tummy tickle on the safe side.


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## Pelorus (Apr 30, 2014)

woodchuck357 said:


> The wide open face notch allows the top to *push* the stem sideways before it breaks off. As the top falls over while still attached to the stem much of the force generated by the fall is directed into the stem which is free to move in the direction away from the top. The major whip was caused by the top *pulling* the stem in the direction of the fall then releasing that pull when the rope broke.



You are suggesting the top is pushing or pulling the stem? (Or both?) 
The thickness of the hinge wood is a greater influence on stem reaction than notch configuration, imo.


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## Toddppm (Apr 30, 2014)

Looks like he had his climbing line tied almost horizontally in another tree and the top caught it on the way down and whipped when it finally fell off the line? Or it was a tagline for some strange reason? You can see it on the right side after he stops ragdolling around.
Without the top catching something like that it would have never been that violent.


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## woodchuck357 (May 1, 2014)

Pelorus said:


> You are suggesting the top is pushing or pulling the stem? (Or both?)
> The thickness of the hinge wood is a greater influence on stem reaction than notch configuration, imo.


The falling top first pushed the stem, then after breaking off and being caught by the rope it pulled the stem. Using a fairly deep, narrow notch or box notch that closes, breaks off while the top is still close to vertical pushes the stem less and results in less whip when the top can free fall. The way it was cut explains why he started to get moved around before the top broke loose.
The effect of notch configuration on stem movement can be easily observed when topping tall slender pines from a bucket.


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## TheGoodFellers (Dec 30, 2014)

look at 38 seconds (strong) seems like the top landed right into the rigging line and it snapped his lowering system. look at that stretch.... -_-


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## Stihlmadd (Dec 31, 2014)

norfolk island pine is very whippy when energised, I generally do not enjoy roping a norfolk top back onto its self and have had groundys snap a lowering rope by placing too many wraps on so the top won't run


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## New Hampster (Jan 1, 2015)

Was the main cause in that he took too much top? Looked like 1/3 of the entire tree. Shows how much back force there can be on a stem when a tree starts toppling.
He knew he was in trouble before the top even left. I hope he recovers. 

Is it the climbers responsibility to double check clearance and rigging?? 
Isn't it HIS job site?


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## TaoTreeClimber (Jan 2, 2015)

look at 38 seconds (strong) seems like the top landed right into the rigging line and it snapped his lowering system. look at that stretch.... -_-

Ouch!!!!!. Looks like he was using a loop runner and a biner as his lowering system. When that failed it was like releasing the string on a drawn bow. I have rigged tiny tops out like that, but that was like 1/3 of the tree. It didnt help that he was weak kneed up to the trunk and didnt push himself off on the spar when that top went.


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## Stihlmadd (Jan 2, 2015)

if you watch it the rope goes at the bad bend radius of the biner, probably just before that sling was about to pop anyway and being side loaded to the building on his left with the climb line made things worse not better.


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## acer-kid (Feb 20, 2015)

Locked off at the porty, id say. WAY too sharp of a bend radius, running over that biner like that.. And it seemed to have a lot of hinge. Shitty shitty set of circumstances.


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