Video of Cobra System on windy day???

Macro,

I personally put steel cables in any tree with included bark, V-shaped crotch or cracking. The pin oak you show doesn't seem too bad but it still has included bark so I would have put a steel instead of a Cobra. Even though the Cobra is working properly, I think the codominant stems may still be able to over extend and break.

I would put a Cobra in a U-shaped crotch that is too large to correct with pruning or has some type of defect in the stem. These are just my opinions and experiences but would also be willing and interested in what others have to say.

-Tyler
 
I kinda figured steel would be better. This is my neighbors tree and I installed/pruned and will growth regulate without charge cause he is a friend and I like the tree.

But it seems if cobra is only to be used with no included bark and U shaped crotch, how often would we need it? Not very often in my case.

I may go back and put steel in this one if that seems to be the consenus.

Thanks
 
Static it is.

I have thought about trying to reduce the smaller lead, but would you just reduce it in stages until it was between 1/4 - 1/2 reduced? Then hopefully the new central leader will fill in the space with new lateral? Also, would you leave a cabling system in even if it were at the top of the subordinated leader?

The growth regulator is for 1 my own personal experiment because I live across the street and can keep track of changes, and 2 there is another pin oak next to it and the canopies are almost touching and one side is begining to get more deadwood every year. I figure the growth regulator will slow down the competition/one sided trees.

I have worked on other properties similar where the pin oaks shaded each other out and they are like half trees, every year more big dead limbs.

Tom, are you not a believer in the use of growth regulators? I think there is a time and place and it does have its uses, but I am skeptic that it really provides all the benefits that have been claimed.
 
The cobra seems to be doing the job, for now. Torsion aka twisting is the concern is see from the bleachers. Short span so less of an issue than on the tree at the college in the november article, which had a lonnng cobra on a leader that failed so catastrophically.

"Fused" uhhh i dunno; have you been able to inspect that fork? Looks like a very bad union that would not be improved at all by spreading, ergo = static system imo.

TGR definitely seems to fit; tree is big and getting bigger. With steel you can have a lighter hand with the saw--focus on the laterals in the codom that actually touch the dominant leader; i use a 30 mph wind as a minimum.

nice vid, and description of assessment. :)
 
Aaron, I would not argue that there may be a time and a place for growth regulators, but in general, I find them to be counter to what we as arborists do. I might go so far as to say that they are unnatural, but much of what we do falls into that category, so I'd rather not open up that philosophical can of worms.

As far as the reduction, yes, I would do it in stages, and yes, I would remove the old support system if there were one at the top of the smaller lead.

-Tom
 
I have not yet read the reduction guidline post yet and this may sound very remedial to you guys.

But basically would you recommend making the 1st reduction cut about 3in diameter, down to a big lateral, taking an estimated 15-20ft out of the top?

Also, after doing this leave the cobra, install a steel, take out all cabling???

I have never tried to corrrect a double leader on a tree this size. I guess I have always figured it was too late and relied on thinning and cabling.
 
Don't cut down or greatly reduce the double leader, the Tree is as it is and any big reduction will end up weakening the double leader and increasing the amount off stress regrowth. What will result in a non-natural character off the pinnoak.

The cobra cabling with shock absorber in it is great, it helps the double leader preventing to completely breaking out and it is much better as using a static cabling system such as steel wire.

If the double leader would be cabled with steel the system off the tree just will stop making extra strenght grown wood for stabilizing this weak crotch and the top will become weaker and weaker in the future.

Dynamic cabling will have the big advantage that the tree moves naturally and starts stabilizing weak spots and will strenght up because off natural movement in windy conditions wich make the chemical process off smart extra strenght-growth possible. And the dynamic cable will only help in extreme overload situations in wich the crotch is most likely to fail.
The system gives an extra safety for environment and will prevent the whole stem to get ripped open in harsh wind conditions.

Only when the whole double leader is allready split open all the way a steel cabling is in place for preventing to drop out the leader and help the tree with overgrowing this wound. befor it will only weaken the species and will do more bad than good .

but thats how we here in the netherlands generally think about cabling and dynamics in trees.
 
You MUST read the reduction guideline post! It is genius, and simplifies alot of potential quandaries of reduction pruning!

With regard to your tree, follow the 25% foliage rule on the lead as if it were an individual tree, and cut the tip back to an acceptable lateral using the 1/3 rule.

I think I am misunderstanding the cable/cobra issue... Are you saying there is a cobra AND a cable currently in the tree?

-Tom
 
Treestyler, your approach is very similar to mine. I also wanna explore all options. I think we may never come to a conclussive rule for static vs dynamic, but I know I'll learn a lot by discussing.

I do have concerns about making large reduction cuts like:

how long will the tree look disfigured?

that large wound may further decay down the trunk and never "heal over".

a cabling system may not be practical if it is at the top of the subordinated leader, therefore the new central leader no longer has that support.

We do need a cabling forum.
 
It's quite simple.

Static cabling for all the things that are not able to support itself anymore or are allready broken, damaged.

Dynamic cabling for all the things that have potential for failure but still are selfsupporting.

Rule off pruning will be around 20 % off foliage and drastic reduction is in my opinion just a bad idea and does more damage to the image off the tree and will cause a lot off wrong re-growth.

BUT there are many cases/trees where things are differtent and circumstances will have to make you impovise and do what ever you think is best for the tree. Thats what makes our job so interesting. And thats why we will allways be discussing this subject and many others.

for this pinoak it seems to me like it's perfectly cabled and with normal reduction pruning every 6 years or so it will be good as gold ;-)

wouter
 
"Don't cut down or greatly reduce the double leader,"

totally agree--small cuts make a big difference

"If the double leader would be cabled with steel the system off the tree just will stop making extra strenght grown wood for stabilizing this weak crotch and the top will become weaker and weaker in the future. Dynamic cabling will have the big advantage that the tree moves naturally and starts stabilizing weak spots and will strenght up because off natural movement in windy conditions wich make the chemical process off smart extra strenght-growth possible."

I hear this a lot from proponents of dynamic systems, and it seems exaggerated. Reaction wood is still stimulated to grow with static systems, just less, perhaps. This is all theoretical; no studies I know of on it.

"And the dynamic cable will only help in extreme overload situations in wich the crotch is most likely to fail.
The system gives an extra safety for environment and will prevent the whole stem to get ripped open in harsh wind conditions."

Not sure that one cable will prevent failure from twisting. Depends on load of course, but ANY movement in that fork will tend to open it up.

"Only when the whole double leader is allready split open all the way a steel cabling is in place for preventing to drop out the leader and help the tree with overgrowing this wound."

How can the tree overgrow such a split? How open does a crack have to be before dynamic fans would call for steel? Has anyone checked this fork out yet? I'd bet dollars to donuts there's rot in there.

"befor it will only weaken the species and will do more bad than good. but thats how we here in the netherlands generally think about cabling and dynamics in trees. "

it's the general european view. A closer look has to made to biomechanics. Trees with static systems still move and adapt to movement.

where is this reduction pruning post?
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Reduction pruning graph
 
Re: Video of Cobra System-Use a hybrid system

What you're supporting is the load of the two leaders on the codom union. Adding any sort of cable high in the canopy does very little to support the weak union.

First, the weak union needs to be supported, not the canopy. I've used different combinations and placements to support the large wood down low.

Installing one or several large through bolts with doubled washers, not just one below the split is the first task. Using two washers assures that the washer won't get pulled into the tree as it moves. Too often I've seen single washers puckered from movement.

Another option is to add a second washer on the outboard. Here is what you'd have:

Tree
Doubled washers
Nut
Washer
Nut-leave one or two threads then peen over the ends

The second washer will be enveloped by the tree as it grows giving the bolt anchor more 'bite' kind of like the flukes on an earth anchor. There won't be any more decay under the second washer because of CODIT. The wound is the diameter of the bolt, under the doubled washer.

Sometime adding one or several through bolt above the union is the best choice. This is where the understanding of tree movement comes into play.

In this tree there is still a LOT of wood above the codom union. Installing a steel cable down low serves the purpose of a flexible brace. It's not good to install solid braces where the tree may flex sideways. The braces will get cycled like paperclips and become weak. Using steel cables instead allows some rotational movement and supports the weak codom.

Once the codom is supported you can design the upper support system. I always used dynamic cables after supporting the codom or cracked union was braced. In effect, the through rods or flexible bracing becomes the 'union' and should be designed strong enough to have as much strength as the solid trunk.

If you don't support the codom or cracked union you need to consider where the tree would split in a storm or failure.

The oak in the vid would likely split all of the way to the ground. There is no fusing going on at the codom. The wound wood is flowing over each side but not blending.

In order to calculate the mythical 2/3 point for the upper cable location you need to measure from the ground, or, where the tree would split if you don't use braces.

My pictures of the hybrid systems that I've installed are on my PC which is dead in the water...the power supply is belly-up. I guess now I have to pump life into the dark side to get my pics onto my Mac.
 
Re: Video of Cobra System-Use a hybrid system

Here's a picture of a failed washer.

The corky bark should have been shaved down so that the washers could seat against solid wood. NEVER deep enough to expose the cambium though.
 

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Re: Video of Cobra System-Use a hybrid system

"Don't cut down or greatly reduce the double leader,"

I think I am a little confused about the difference between crown reduction and canopy thinning.

I always picture crown reduction as focussing on taking portions off the top back to laterals, being somewhat of an extreme measure (not that I disagree in any way).

Then canopy thinning leaves the overall tree height intact but removes laterals evenly throught the canopy which accumulatively reduces a lot of weight.

?

I am very comfortable with extreme crown reduction on smaller trees but lean towards canopy thinning on large mature trees, but maybe thats because I have not got the chance to see others results.

(kinda in my own world here as my previous tree topping vid post would indicate, thats why treebuzz is so helpfull)
 
Re: Video of Cobra System-Use a hybrid system

Some-one should indeed pick up some investigation in the differences between static and dynamic cabling.

What i've seen here on old cabled and fixated trees and what i have seen on dynamic cables I personally know enough. But it's just what you can see in the field and does not include a scientific backup.

Maybe a good thing to invest in ,monitoring this and figure out what is best to do.

In some cases I think a hazard-wooden style-fence around the tree and no cabling or correction pruning or topping at all will be the best solution and will make the most beautifull trees. We are sometimes just to eeger to try to fix and control everything.

nice discussion although
 
Re: Video of Cobra System-Use a hybrid system

As an addendum, let us not forget to define the hazards and the tolerance for risk. What are the targets? I am sure they are there, but what happens if the tree fails? This must be factored in.

Also do not forget a thorough root system inspection. Proper cabling will/may significantly enhance load on the root system. Is it stable? Can it handle the increased load in the future as the tree grows?

I agree with the discussion and think it valuable.

To answer the original question directly: Yes
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Tony
 
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