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Mechanics of an heavy bending 1 year 2 weeks ago #63094

  • BofhSkull
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Hi everyone.

I have a sabina juniper that is being worked on. Not going into detail about the stages, but one of the things I'll need to do to it is (if at all possible) bending a portion of the main trunk that is just too straight.

The trunk is, in that specific point, about 1.5-2 cm thick and very stiff, so I suppose the actual bending will need to be done in several stages.

I've never done anything like that, so want to be cautious and make sure I'm doing the correct steps.
Part to be bent will be protected with raffia first, then electric tape. Around that, thick copper wire (6mm or so).

But then what?

Given the above, the wire alone won't be enough, so I guess I'll need to place something (piece of wood?) on the side of the trunk, and use that as a pivot for the actual bending, while using guy-wire anchored to both sides of the trunk to apply the tension needed?

How to make sure this won't harm the trunk in the point of contact?

How many steps of "further bending" can be considered safe, and how much it's good to wait before "giving it another push"?


Anyone with a good reference on how to do such an operation?


Thanks in advance...
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Mechanics of an heavy bending 1 year 2 weeks ago #63095

  • Bunsen33
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Have you considered cutting a wedge out of the inside of future bend to help things along? Removing some of the bulk on the inside of a bend can make it easier to achieve the desired configuration with less stages and alleviates some of the force resisting the rigging (wiring, guy wires) you are using.
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Mechanics of an heavy bending 1 year 2 weeks ago #63096

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Bunsen33 wrote: Have you considered cutting a wedge out of the inside of future bend to help things along?


Not yet: I know it's an option, but I consider it even riskier than the bending itself for a juniper (and a rather old one, in this case) since unlike deciduous they don't heal over that easily.
But maybe I'm wrong.

Understanding how to approach this is indeed the reason for this post...

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Mechanics of an heavy bending 1 year 2 weeks ago #63103

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Our club had a presentation last fall where removing a wedge was demonstrated live with a pine (Japanese black pine I think) and with two set and healed examples in the room, also pines. Pines and Junipers are this guy's thing.

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Mechanics of an heavy bending 1 year 2 weeks ago #63109

  • leatherback
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Cutting sections out of a trunk can easily kill the rest of the branch. Do NOT do this do valuable material unless you REALLY know what you are doing. It sounds like this is valuable material.

If you want to bend big branches, soaking the segment for 24hrs may help. I have successfully bent branches of 2-3 inches on juniper. Key is going slow. In some cases, it may take weeks to set the bend.

Do you have a branch bender? And I do not one of those tiny 3-point screw on things, I mean a long lever with a prong on the end, or a windable branch bender.

It is important to find placed for good Guy wires. Consider putting a screw in the right spot. If you have good connections, you can do a small bend. Fix. Bend more half an hour later, and tighten the guy wire. This way we set a 120 degree bend in a 2 inch branch over the course of 3 weeks at a friends place.
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Mechanics of an heavy bending 1 year 2 weeks ago #63116

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leatherback wrote: Cutting sections out of a trunk can easily kill the rest of the branch. Do NOT do this do valuable material unless you REALLY know what you are doing. It sounds like this is valuable material.


Yup. That's exactly what I fear. I wouldn't worry about attempting that on -say- a maple. But cutting the live vein in a juniper takes one second, and at that point I'd likely lose half of the tree.

leatherback wrote: If you want to bend big branches, soaking the segment for 24hrs may help. I have successfully bent branches of 2-3 inches on juniper. Key is going slow. In some cases, it may take weeks to set the bend.


This is a precious suggestion. I suppose drenched rag around the trunk, then apply raffia while still wet?

leatherback wrote: Do you have a branch bender? And I do not one of those tiny 3-point screw on things, I mean a long lever with a prong on the end, or a windable branch bender.


No I don't. But getting one would be no problem. I'm in no rush to do this; I need to understand and detail the logistics of it first.

What time of the year would you suggest?

I would have done it about now (not this year, ofc): still a couple of months of moderate growth in the season, and the time of the year with the highest humidity level, here.

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Mechanics of an heavy bending 1 year 2 weeks ago #63117

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Yeah, a wet rag works. Or.. Do it when it is raining a lot so all is soaked. Especially older trees have dead segments and they take up water. But also the old bark gives more when wet.

The raffia is there to ensure the woodfibres (Which will in part tear when bending the branch) do not break out of the bark: It is important to have the raffia on tight. ALWAYS apply it wet as it is stronger & more pliable.

Time of year.. Tricky. I would NOT do it in summer (bark slippage can become an issue, water needs are often higher leading to die-off before damage can be dealt with by the tree). I have done big bends throughout Oktober - May.

The main trunk was a straight branch to the left when we started on it last fall, picture of a few weeks ago after first wiring of the side-branches:

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Mechanics of an heavy bending 1 year 2 weeks ago #63149

  • FrankC
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So, I try to explain my way for heavy bending.
first; Get a good amount off wet rafia around the trunk
second ; if the bend you gonna make to the front (as an example), apply to left and right side of the trunk a wire of a decent size as asupport for the future bend, to small and there is no use for it, to big an it cause trouble while bending
third; fis the whole thing with rafia and wire it.
fourth; now easy bend, fix with guy wire, next day or so do the next bend and repeat next days, weeks, until your bend is bigger than what you visioned.
five; wait, wait, wait
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Mechanics of an heavy bending 1 year 2 weeks ago #63150

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FrankC wrote: second ; if the bend you gonna make to the front (as an example), apply to left and right side of the trunk a wire of a decent size as asupport for the future bend


You're meaning on the two sides of the bend, as opposed to "inside and outside of it", I get?
Just to make sure...

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Mechanics of an heavy bending 1 year 2 weeks ago #63163

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BofhSkull wrote: You're meaning on the two sides of the bend, as opposed to "inside and outside of it", I get?


This is news for me, heavy wires sidelong the branch to be bent.
@FrankC do you have a documented (as some pictures) example? I'm curious too.

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