Cobra bracing

[Wood-be]

Hi all, we were dead wooding and fitting cobra bracing to three 800 year old yew trees for the national trust. Whilst we were there we couldn't help but notice a beautiful cedar in the grounds with cobra bracing in it. Looking closely the previous tree surgeon has made a complete pigs ear with it. Have a look at the photos and see what you think.

 

This is our attempt. Quite simple really.

 

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Edited February 8, 2016 by Wood-be

[Al Cormack]

What's with the curly bits in yours? Not seen that before.

[Wood-be]

In the instructions it says they are a visual aide. These are so you can see if the splice has moved I.e they shrink in size if the bracing and the splice is overloaded. Without these the splices can also come undone.

 

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[Darrin Turnbull]

Hi all, we were dead wooding and fitting cobra bracing to three 800 year old yew trees for the national trust. Whilst we were there we couldn't help but notice a beautiful cedar in the grounds with cobra bracing in it. Looking closely the previous tree surgeon has made a complete pigs ear with it. Have a look at the photos and see what you think.

 

This is our attempt. Quite simple really.

 

Sent from my C6903 using Tapatalk

 

 

Yes well done . You're a little bit short on the protective sheath. Did you use the shock absorber or is the tree already split .?

[Andymacp]

Looks pretty spot on, nice to see bracing done. As above did you use the absorber dong?

[Wood-be]

Yes well done . You're a little bit short on the protective sheath. Did you use the shock absorber or is the tree already split .?

We only just had enough sheath for the whole job. The brace between the two large stems doesn't have an absorber as we had to winch the two stems together due to a very poor union at the base.

 

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[Wood-be]

Looks pretty spot on, nice to see bracing done. As above did you use the absorber dong?

The black dongs were used on the branches but not on the two main stems because of the poor union at the base.

 

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[Andymacp]

That won't really help the poor Union if you've done that. Surely would have been better to bar brace at the Union

[Wood-be]

That won't really help the poor Union if you've done that. Surely would have been better to bar brace at the Union

The union was right at the bottom of the tree. The force on the bar would just snap it. The stems had managed to snap two steel cables which were below the static brace which we had fitted. The whole point of the bracing is not to drill holes into the tree. We try to avoid drilling bars into trees if we can avoid it!

 

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[Andymacp]

Fair enough, but cobra is designed to allow the tree to move so won't winching the stems in at the top will just put unorthodox stress on the Union that they aren't used to.

That's really interesting I've never seen failed steel bracing. What size bar was used? Was there plates and bolts too ?