Author Topic: Watching an arborist today  (Read 3893 times)

dmacdd

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Watching an arborist today
« on: March 20, 2011, 08:31:55 AM »
Today I watched a  team of city arborists take pieces off a tree outside my apartment building. I was hoping to see some interesting use of knots.  I saw only one knot used many times: a clove hitch finished with two half hitches on the standing part.  The man aloft doing the cutting was navigating the canopy in the bucket of a cherry picker. The tree was a very large, very old, maple with some decrepit limbs overhanging our building.  The team consisted of at least six men and three vehicles: A truck with a towed chipper, a cherry picker/equipment truck, and a crane truck with a cargo flatbed for pieces too big to chip. 

A half-inch line (a brown laid rope) for lowering pieces of the tree ran from a man belaying on the ground, to a block attached to a rope sling around  the base of the trunk and acting as a fairlead. The line rose from the block close to the trunk 35 feet vertically into the canopy, where the cutter positioned it successively over crotches conveniently located for lowering the pieces he was about to cut. He tied a clove hitch and two half hitches around each piece he was about to cut, the man belaying below would take up the slack, the cutter would cut the piece with his chain saw, the piece would break, swing, and be lowered to the ground.

It turned out that the most interesting part of this was the judgement being exercised in the choice of the crotch being used to support the line, the location of the knot on the piece to be cut, and the positioning of the cuts to make the piece break and  swing safely.

windyrider

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Re: Watching an arborist today
« Reply #1 on: March 20, 2011, 10:47:00 AM »
Interesting, I work as arborist in France and the knots I use would include Bowline, running bowline, bowline in the blight, figure8, zeppelin bend, double fisherman's, timber hitch, alpine loop, marlin hitch, highwayman's hitch and I'm sure there are others.  Just getting started into this fascinating subject of knots and splices and thought this thread was a good one to get my first posting on the forum. ;D
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Transminator

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Re: Watching an arborist today
« Reply #2 on: March 20, 2011, 11:47:22 AM »
Nobody should be "disappointed" by this use of a single knot to do the work. It was the only knot that was needed for the task. Quickly tied, simple and up the task. Efficient!
Their job is not to use a lot of knots. Its about using the right knot for the task at hand.

knot4u

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Re: Watching an arborist today
« Reply #3 on: March 20, 2011, 08:23:38 PM »
Theory meets real life.

[Inkanyezi] gone

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Re: Watching an arborist today
« Reply #4 on: March 23, 2011, 08:13:36 AM »
I have seen work done in a similar fashion here also done with one single efficient knot, but a different one. A sewn tape sling was wrapped a few times around the portion to secure, and one end passed through the other, effectively making a prusik, which was attached to a hook of the crane they used. The slack was taken up before cutting and all pieces were safely taken to the ground. The sling was invariably attached above the center of gravity of the piece to cut. There was hardly any swing at all when the pieces came loose.
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Dan_Lehman

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Re: Watching an arborist today
« Reply #5 on: March 23, 2011, 06:01:42 PM »
Interesting, I work as arborist in France and the knots I use would include
  • Bowline,
  • running bowline,
  • bowline in the blight,
  • figure8,
  • zeppelin bend,
  • double fisherman's,
  • timber hitch,
  • alpine->butterfly loop,
  • marline hitch,
  • highwayman's hitch

That's a pretty good set of knots, Windy.
(I suspect that we'll see that your crew are doing things
that the one-clove-hitch-only worker might not do.)
But here it's worth pointing out that what seems to be
an essential knot of arborists --beyond the running bowline :
some kind of friction hitch-- isn't listed (as for the
clove-hitch-only fellow, that knot has been so used,
perhaps it was in laid rope, where there was much friction!).

Please tell us how/where these are employed.
Also, to be sure, what do you mean by "figure8"
--bend / eyeknot / stopper--,

and "double fisherman's"
--an end-2-end joint (aka grapevine bend) /
or a noose-hitch (aka barrel knot (noose hitch)/
or tail tie-off (aka strangle binder)-- ;

these two (boldface) names are used in the various ways indicated,
and esp. in some cases w/arborists, it seems.

Thanks,
--dl*
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dmacdd

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Re: Watching an arborist today
« Reply #6 on: March 24, 2011, 04:43:33 PM »

 (as for the
clove-hitch-only fellow, that knot has been so used,
perhaps it was in laid rope, where there was much friction!).


It was laid rope, synthetic, colour brown, or rather khaki, diameter about 1/2" (13  mm).

Dan_Lehman

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Re: Watching an arborist today
« Reply #7 on: March 24, 2011, 06:48:09 PM »

 (as for the
clove-hitch-only fellow, that knot has been so used,
perhaps it was in laid rope, where there was much friction!).


It was laid rope, synthetic, colour brown, or rather khaki, diameter about 1/2" (13  mm).

But you're missing the point: the clove hitch can be used qua friction hitch
in such instances (but your user was in a bucket, not swinging around);
yes, as a terminal hitch "to the spar," its use is seen, as is the running bowline.
Btw, the clove can take a collar much as can the "cow & better half"
--a cow hitch secured with a half-hitch (which should be better
oriented than is commonly shown, giving a good securing).

--dl*
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