Cabling a spreading silver maple

I've used a little bit of everyone's ideas exept reduction, that only makes things worse.
Go to brafasco and get a couple of lengths of 3/4 grade 8 threaded rod. Drill through one of the smaller leads just above the union and use this for a guide hole to align a long bit (have a local welder fab up a 6' +\- bit, use an 8" long 3\4 and 1/2 round bar so the long bit has reduced friction and chip extraction) and make your through bolts. Next cable th crown with the 2/3 rule except use 3/8 amen eyes and rod with 7/16 cable, as lags like to pull out of small dia. silver. I've used this in the city with monster silvers for years without problems. The only difference is the size of tree dictates the size of amens and rod for cable.
 
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I've used a little bit of everyone's ideas exept reduction, that only makes things worse.

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Can you explain how reduction makes things worse?

-Tom
 
Up here, silvers sucker up so quickly and profusely, that the weight quickly overtakes what would be there if left alone. They also decay so fast you can watch it, therefor reduction is not perhaps the best option.
 
Reduction is a good option.. little decay in the branch tips is acceptable.. You just don;t want to be making cuts over 4" if avoidable, and especially not on the main stems.. keep most reduction cuts under 3" and tree will be fine.. cable where the wood is 6-8" diameter no matter how far from the crotch it is... Brace is needed if there will be twisting, as with 2 large co-dom stems.. I wouldn't worry about it, if it is just a big limb..
 
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Up here, silvers sucker up so quickly and profusely, that the weight quickly overtakes what would be there if left alone. They also decay so fast you can watch it, therefor reduction is not perhaps the best option.

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If the cuts are small enough, like Daniel indicated, suckering and decay can be kept to a minimum. We have done a number of large Silver Maples and White Pines this way with little to no adverse effects. I'd like to see a pic of the whole canopy to get a better idea of the possibilities, though.

-Tom
 
The point of cabling high is to get the most leverage, but if it gets you to twigs, that's no help at all.

I would consider opening up the acceptable cabling range from 2/3rds of the canopy alone to 2/3rds of the overall height of the tree. Mrtree is right - cable lower than what you were previously thinking.

You want to find a pair of opposing limbs that come from opposite sides of the split and put in one cable at minimum. Two cables would be ideal, but both cables anchored on opposite sides of the split. When you have multiple splits, you need even more cables.

I'm not a huge fan of installing bolts unless you've got a definite crack or clearly have included bark. Then you already have decay issues, and a bolt is going to do much more good than harm.

Bits with extensions are unwieldy, but long threaded rods also flex, so it's not a loss if there's some travel on the hole being drilled, provided it still is going through the center of the tree.
 
Here is a picture of the entire tree in question. Keep in mind this maple is what we consider as mature and will not grow more than maybe 25% in all directions.

Any cabling or bracing treatment would of course be combined with limb reduction for outer limbs and some light crown thinning for the top.

At two thirds height from the crotches (or the groud) there are no fewer than a dozen branches of similar size. If I were to connect two together with a cable I would be supporting half the tree on a 6 inch limb. I could put in 6 cables or so and reduce the limbs that aren't supported. A spoke wouldn't really fit.

We have installed only bracing rods without canopy cables in similarly formed yet smaller trees. If training was an option then that was combined too.

With this silver I think a combination of bracing rods with pruning would be enough. I think that a cable just above the crotch would be stronger than a 8 foot long threaded rod. I have seen a threaded rod break, being fatigued from lateral swaying. A cable wouldn't fatigue from swaying however j lags are a weaker anchor.

Thoughts?

Vince
 
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Here is a picture of the entire tree in question. Keep in mind this maple is what we consider as mature and will not grow more than maybe 25% in all directions.

Any cabling or bracing treatment would of course be combined with limb reduction for outer limbs and some light crown thinning for the top.

At two thirds height from the crotches (or the groud) there are no fewer than a dozen branches of similar size. If I were to connect two together with a cable I would be supporting half the tree on a 6 inch limb. I could put in 6 cables or so and reduce the limbs that aren't supported. A spoke wouldn't really fit.

We have installed only bracing rods without canopy cables in similarly formed yet smaller trees. If training was an option then that was combined too.

With this silver I think a combination of bracing rods with pruning would be enough. I think that a cable just above the crotch would be stronger than a 8 foot long threaded rod. I have seen a threaded rod break, being fatigued from lateral swaying. A cable wouldn't fatigue from swaying however j lags are a weaker anchor.

Thoughts?

Vince

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I think your thoughts on this are well formed, and the rest of us are speculating. I like what you are suggesting, it sounds reasonable.

-Tom
 
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At two thirds height from the crotches (or the groud) there are no fewer than a dozen branches of similar size. If I were to connect two together with a cable I would be supporting half the tree on a 6 inch limb. I could put in 6 cables or so and reduce the limbs that aren't supported. A spoke wouldn't really fit.

We have installed only bracing rods without canopy cables in similarly formed yet smaller trees. If training was an option then that was combined too.

With this silver I think a combination of bracing rods with pruning would be enough. I think that a cable just above the crotch would be stronger than a 8 foot long threaded rod. I have seen a threaded rod break, being fatigued from lateral swaying. A cable wouldn't fatigue from swaying however j lags are a weaker anchor.

Thoughts?

Vince

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Clearly you cannot meet so called standard cabling methods. Perhaps short low cables or braces would be better.

IF you have seen braces fatigued (and broke?) by swaying than the crotch (and split) has not been stabilized by the braces, therfore no need to think of this as the way braces act.

As for cables being stronger than threaded rod have you done calculations to show this? Surely you need to compare the cable and anchors (if any) with the threaded rod and washers used.

Are you in a no win situation with this tree? You cannot do the standard methods so perhaps you cannot meet the municipality's requirements.
 
Standard is something that is written in a book... a tree is not a book and to date no book comes even close to accounting for all the variables involved in trees... a lot of practical experience, some book knowledge and a dash of creativity goes a long way in creating reasonable and affordable solutions in such situations..
 
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Clearly you cannot meet so called standard cabling methods. Perhaps short low cables or braces would be better.

IF you have seen braces fatigued (and broke?) by swaying than the crotch (and split) has not been stabilized by the braces, therfore no need to think of this as the way braces act.

As for cables being stronger than threaded rod have you done calculations to show this? Surely you need to compare the cable and anchors (if any) with the threaded rod and washers used.

Are you in a no win situation with this tree? You cannot do the standard methods so perhaps you cannot meet the municipality's requirements.

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Quite right about the broken brace. One rod isn't enough to hold a crotch of a leaning tree. Just a little twisting will fatigue the metal enough to break it.

I'm not familiar with any numbers describing holding strength of j lags vs. through bolts by species. Also not familiar with numbers comparing forces applied to hardware in the canopy (2/3 standard) vs. at a crotch. Is that even out there?

I'd love to go back to school and study this by pulling big trees apart and measuring forces. that would be a big budget set of experiments.

The municipality doesn't have any set standards so i essentially have nothing to meet. I do need to be able to describe my logic in any treatment that I prescribe and that is the challenge with a tree like this.

v
 
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Reduction is a good option.. little decay in the branch tips is acceptable.. You just don;t want to be making cuts over 4" if avoidable, and especially not on the main stems.. keep most reduction cuts under 3" and tree will be fine.. cable where the wood is 6-8" diameter no matter how far from the crotch it is... Brace is needed if there will be twisting, as with 2 large co-dom stems.. I wouldn't worry about it, if it is just a big limb..

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I agree and this weed will come back. I've topped these trees before but the cuts were about 2/3 up and they look great. Can't even tell that they were topped. I did try a suggest another option but the guy wanted them topped down. Will try to post a pic.
 
I'm not familiar with any numbers describing holding strength of j lags vs. through bolts by species. Also not familiar with numbers comparing forces applied to hardware in the canopy (2/3 standard) vs. at a crotch. Is that even out there?

*There is lots of literature available if you search. Some may not be specific but you will get the idea. Check out books such as those produced in association with the tree mechanic confrences.*


I'd love to go back to school and study this by pulling big trees apart and measuring forces. that would be a big budget set of experiments.


*You can easily pull trees apart (well small ones at least) and measure forces. Some amsteel cable and slings, a really heavy immovable object, and a tirfor. Add on a dynamometer and a digital micrometer and you can measure force of pull and movement in cracks etc.*



The municipality doesn't have any set standards so i essentially have nothing to meet. I do need to be able to describe my logic in any treatment that I prescribe and that is the challenge with a tree like this.


*So does the fact that you are the most knowledgable in the area(?) and are attempting to save a tree win the day? Does a reasonable appproach win?

I think the tree is easily savable for a decade or two. Beyond that I think the tree will need to be reexamined and support mechanism reconsidered.*
 
*So does the fact that you are the most knowledgable in the area(?) and are attempting to save a tree win the day? Does a reasonable appproach win?

-Whatever approach keeps the tree from failing over the next decade wins. Fortunately my knowledge and experience is yet unrivaled locally but i still need to justify my prescription to anyone that asks.

I think the tree is easily savable for a decade or two. Beyond that I think the tree will need to be reexamined and support mechanism reconsidered.*

-Agreed. We have a situation with our boulevard silver maples: they comprise something like 50% of our street tree canopy cover but only 20% of individual trees which means that we have a huge proportion of mature to over mature silvers, most with far worse structure than this one in question. Extending the life of one tree for 20 years is crucial to maintaining target canopy cover levels while many of the others fall apart or are condemned.

vince
 
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I did try a suggest another option but the guy wanted them topped down.

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There is no try, only do. -Yoda

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DO or DO NOT... there is no try....

I just hate it when people misquote the Masters....
 
Har har, I'd be careful about installing J-lag low in the tree. I've seen it twice where they have been ripped clean out of the trunk. To boot it is silver which isn't the best compartmentalizer. They could have been installed wrong, who knows, but what about a through bolt with an eye to which cable can be attached to? To invasive? Now, I know twice is hardly concrete evidence but I would figure with installing the cables higher in the tree there your just limiting the ability of the tree to reach that breaking point which would produce less stress on the cable and lags as the tree is still allowed to move and take the shock (yes I know static cabling is supposed to limit this, but wind is a pretty impressive force to try and stop dead, I mean street lights go nuts in wind and their pretty rigid structures). Where lower, if there is still movement its like a dead pull on either of the lags, it's which one wants to go first. Again I could be completely wrong on this as I have very limited experience with static cabling. More or less just using common sense to try to justify it.
 
Why even use lags or through bolts? Use some Cobra (or Boa) and forget about drilling, wounding, dragging cable etc. You still likely need to brace below the union.
 
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