Cables and bolts

cory

Tree House enthusiast
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This came up OTJ recently. A large white oak with a high large crotch with an old split in it, showing signs of minor increased splitting. I normally recommend cables as they have the most leverage/strength. Are bolts thru the crotch helpful? I've always wondered because they are so low they have zero leverage. Thanks
 
Picture?


I think that there is a component of "reverse" pressure, or a lever. When the tips move toward each other, the fulcrum point in where the two sides part, with the pressure exerting apart at the lower end of the split.


http://www.treestuff.com/store/catalog.asp?category_id=75&item=585



It specs the size, placement, number of rods based on size.

I've wondered how often two cables are better than one, in a large, heavy tree.
 
I find it interesting that in the homeland of suing people over the most ridiculous things, arborists cable and brace hazard trees, whereas were I live, we simply tell the owners that their trees are dangerous and should be put out of their misery.
 
Get aggressive with that weak branch. Retrenchment pruning with a cable and rod will preserve a cool mature tree for quite a while.
 
Cabling is a good thing.
It's up to the clients accepted level of risk.

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I do some cabling.

I would like a good document to have signed by the client, if anyone has one to share.

sean @ south sound tree.com
 
Bracing is good for splitting crotches, strengthening on multiple axis to bind the split... the cables help mellow the wowie of the canopies forces on that crotch....and of course end weight the limb before the cable...then you can use the cables tautness as an objective indicator for end weight... end weight focusing on the ends...stay in 2-4 inch cuts that have yet to develop a "heartwood" and easily callus over.

Or something.

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Man, we used to do tons of cabling and then POOF - we never did it again.

I always wondered why - I bet a nickel it was cuz of potential liability issues.

The most we ever seemed to do was lighten, never cabled again.
 
Cory, get the BMP's, The Tree Support Systems: Cabling, Bracing, Guying, and Propping. There is no need to fear saving a tree. It is not your tree and not your responsibility. All you can do is inform your client of what the situation is ( including the ramifications of large limb removals ) and then do what they decide to have you do and then do it according to industry standards.
 
Ill use cables to prevent failures, i dont think cables and rods should be used to fix failures. In todays world at least. I always think about Deva's run in, and his $20-30k dollar swing.
 
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  • #19
Ha, The Swing!


I know there are BNPs etc, I'm just wondering, from those with hands on experience, how bracing does much good beyond what cables are going to do.
 
It will depend on the circumstance, but when needed they do a much better job at immobilizing the split. A cable alone can support the weight but it may not keep the split area from those slight movements that would prevent good wound sealing.
 
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  • #21
Ok that makes sense. Although most if not all splits will never heal strongly so if cables will always be needed and the split will always be there, why bolt it? Bolts seem like a lot of work for little likely return.
 
Never is a long time, Cory. A split may or may not be able to fully support the limb on its own but the closing of the wound and the associated new overlaying wood will be better for the tree's health and structure than the alternative.
 
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  • #23
I appreciate the responses. :thumbup:
 
I just climbed a big old English oak after a storm, I had to do some pruning where branches had broken out, and some end weight reduction.
While I was working on one large branch that had had two fair sized limbs twist and break out...I saw what looked like the end of a broken cable, then I realized it was solid, then I saw the bolts.
This branch, probably a good 12-16" diameter had three old through bolts in it, and sitting back and looking at it I could see where the split had been. Hard to say how long ago it had been bolted, but very interesting in that the failure of the limb was way out in front of the bolted section, the old split showed no signs of any movement at all.

It had only been bolted, there were no cables in it.

One of the branches that had broken came out of the bolted section, below and between the bolts. It had broken a good 5' out from the branch union. I actually left a fair sized stub, only cut back to just past the splintered section, my reasoning being that to introduce a fairly large (8-10") wound below and between the split and bolted section might not be a good idea...the branch was 'used' to that lower bit being there to help support the old split.

So there.
 
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  • #25
Good info and good decision re the stub, imo.
 
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