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<James Scarlata>
posted
My copy of ANSI Z133 is from 1994 and states that climbing ropes should be at least1/2 inch diameter and have a tensile strength of 5400#. Has this standard been revised since then. I see a lot of mountaineering ropes that are 6000 to 8000# tensile but only 10 to 11 mm diameter.
 
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<Louie Hampton>
posted
Reply to post by James Scarlata, on April 03, 2003 at 23:52:54:

The 2000 revision has an exception that allows the use of smaller diameter line so long as it meets the strength and elongation requirements for the half inch line, "provided the employer can demonstrate it does not create a safety hazard for the arborist and the arborist has been instructed in its use."

LH
 
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<Guy>
posted
Reply to post by Louie Hampton, on April 03, 2003 at 23:52:54:

The 2000 revision has an exception that allows the use of smaller diameter line so long as it meets the strength and elongation requirements for the half inch line, "provided the employer can demonstrate it does not create a safety hazard for the arborist and the arborist has been instructed in its use."

Thanks Louie for looking that up for Jim. His question may have come about after seeing me climb with 10mm mountaineering rope. I asked Don Blair about this at MAC-ISA last Oct. and he said the weight # was 5000 lbs. and the important part was in the text you quoted.

Glad to see ANSI allows some commonsense flexibility; much like heading cuts being recognized as proper pruning technique even if some people still think that all stubs are evil.
 
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<Mark Goodwin>
posted
Reply to post by Guy, on April 24, 2003 at 09:28:54:

Guy, would you please clarify and expand on the subject of leaving stubs (with examples)? Also, a brief quote from the standard as it applies? (Thanks.)
I'm imagining you mean something like leaving large major scaffold bases such as when a large old tree has lost an excessive amount of canopy suddenly, and in an attempt to conserve photosynthetic surface area and reduce wound surface area.
Also, I assume, with a clear understanding that the remaining stub (branch base) is safely secure. And I assume that followup care is part of the deal, so that epicormic flaws, & etc will be addressed when they develop?
(I saw reference to this in a previous post, but I couldn't remember where.)
 
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<Guy>
posted
Reply to post by Mark Goodwin, on April 27, 2003 at 09:03:45:

Mark, see the April issue of Tree Care Industry magazine for a 2400-word article on the subject. The pictures were supposed to be interspersed to illustrate better, my fault for not doing so.

Your assumptions about secure bases and aftercare etc. are all correct. Working on a followup focusing on protocol and aftercare. Wish ISA paid for submissions; I'd rather have gotten it to a wider audience (I enjoy feedback--one guy pronounced the concept "a preposterous truckload of tripe" at first but has totally bought in since I beefed up references to the literature), but working for free has lost its appeal to me lately.

If you can't find a TCI mag (they're free via www.natlarb.com) I can email you the text.
 
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<Mark Goodwin>
posted
Reply to post by Guy, on April 29, 2003 at 11:32:03:

Thanks,Guy. I Downloaded the PDF of your article. I'll read it more thoroughly as I find the time.
 
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<Mark Goodwin>
posted
Reply to post by Mark Goodwin, on May 01, 2003 at 17:51:25:

I finally read the whole article, and darned if you didn't make me think!
The practice of pruning to branch collars, when done on a modest scale, leaves a tree that can look "unpruned" to the casual observer.
Combined with less epicormic sprouting, and the ease of deciding on pruning targets, this is clearly an easy style of pruning to do and monitor.
It is attractive also because of the sense of completion.
It's those special cases you present, which challenge our basic understanding and makes us think of the larger context.
It has been a challenge to understand and communicate the reasons for target pruning. I think it may also be a challenge to do this with conservative-restorative pruning, including the investment in followup care.
Luckily I don't have to deal with hurricane damage!

It is relatively easy for me to buy the concept of conservative pruning to nodes in cases where great loss of canopy has occurred. It becomes less clear to me in cases where the loss of major branches is asymmetric or where a single large branch has broken, leaving a sound lower attachment.
If regrowth from a stubbed branch will be shaded by the remaining canopy, often it will not produce food sufficiently to sustain itself, the reason for limiting the removal of leaf bearing volume on each branch.
How do we decide how or if to accomodate the light needs of this branch through crown thinning? Or, by further reducing the length of the remaining stub, can we balance its total energy needs with the regenerating supply of foliage that will feed it?
 
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<Guy>
posted
Reply to post by Mark Goodwin, on May 02, 2003 at 11:45:27:

"It has been a challenge to understand and communicate the reasons for target pruning. I think it may also be a challenge to do this with conservative-restorative pruning, including the investment in followup care."
3-5 years later you thin sprouts and remove parts that did not sprout. 3-5 tears after that you thin again and that's usually it. Customers agree to it with no problems, considering that the alternatives are lopsided trees with more sunscal decay and storm damage, or stumps.
But you're right, it is a huge challenge to get some folks away from lateral pruning. (Actually latent nodes, some of which have the "collar" shape, are just as much natural targets as collars at laterals.)

"Luckily I don't have to deal with hurricane damage!"
Ice storm damage is far harder to repair.

"It is relatively easy for me to buy the concept of conservative pruning to nodes in cases where great loss of canopy has occurred." Glad to hear it. Tell the world.

"It becomes less clear to me in cases where the loss of major branches is asymmetric"
If it's asymmetric, all the more reason to remove less, to preserve what symmetry remains.

"or where a single large branch has broken, leaving a sound lower attachment."
True. If nearby branches can "fill the hole" with lateral growth, better to cut back.

"If regrowth from a stubbed branch will be shaded by the remaining canopy, often it will not produce food sufficiently to sustain itself, the reason for limiting the removal of leaf bearing volume on each branch.
How do we decide how or if to accomodate the light needs of this branch through crown thinning?"
Seldom, since losing less canopy is the name of the game after nature tops over 50%. Unless thinning is also called for to reduce load on remaining branches (which is often.) If you can wait a season to leave more leaves the first post-damage year, all the better. It's agamble--how heavy will the storms be next summer?

"Or, by further reducing the length of the remaining stub, can we balance its total energy needs with the regenerating supply of foliage that will feed it?"
If enough light will get to it to keep it going.

Many good questions, which I've struggled with while trying to write a followup detailing these decisions and others. Many conditions and caveats arise; the further I get into it at times the less clear it is. Still some principles are standing out so something will come out of it.

The curious lack of feedback from other climbing arborists doesn't make it any easier.
 
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