One of my clients has a medium size green ash in his front yard with a significant frost crack running vertically down the trunk from the first major crotch(about 6'). He wants to save the tree and I'm going to try to sell him a cabling job ( cobra cables, set about 3/4 of the way up the tree height) but would like a little feedback from anyone who has done a similar repair. I am inclined to reject running threaded rod (traditional bracing)through the trunk in addition to the cabling although that would have been the norm for many of the services I've worked for in the past.
cabling and bracing
- Thread starter coydog
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tshanefreeman
ArboristSite Operative
Static vs Dynamic Cabling/Bracing.....
I am not sure how many people receive TCI (Tree Care Industry) magazine, but to those who do, there was an excellent article dealing with static and dynamic cabling and bracing in the February 2002 volume.
Static line cables follow the traditional path of steel materials. Dynamic systems utilize a fabric, typically polypropylene; it is commonly referred to as Cobra cable because the manufacturer of Cobra dominates the US market.
Michael Roche, author of this particular article, states how arborists like steel cables because they are tried and true, they last a long time, the materials are reasonably priced, and they work. While other arborists like fabric cables because there is no drilling into the tree, no tools are required, installing them is easy to learn, and they work.
There are downfalls to both systems:
* when you use steel cables, you wound the tree, leaving an opening for infection.
* steel cables reduce tree sway and with a reduction in taper the tree becomes weaker.
* polypropylene cables, has the potential for photo-degradation, the material seems to stretch over time, one has to employ routine inspections more often, and some say the material is not as aesthetically pleasing.
The benefits of the Cobra system is that the gear weighs less than a rope and saddle and it's so simple to install, the person estimating the job can install a cable on the spot. This makes a tree company more efficient and only adds to the bottom line. Metal cabling requires tools and materials that weigh so much that a separate tree crew is necessary, preferably with a bucket truck. The Cobra flexes in the wind, that is once it is installed properly and the correct slack is achieved.
For more information on this topic, try to get your hands on the pre-described volume of TCI magazine and turn to page 26.
Ultimately, the final decision is up to the arborist tackling the task, therefore, use the system that you feel most comfortable with. As I mentioned above, both static and dynamic have their benefits and downfalls, but what in this industry doesn't?
Shane Freeman
I am not sure how many people receive TCI (Tree Care Industry) magazine, but to those who do, there was an excellent article dealing with static and dynamic cabling and bracing in the February 2002 volume.
Static line cables follow the traditional path of steel materials. Dynamic systems utilize a fabric, typically polypropylene; it is commonly referred to as Cobra cable because the manufacturer of Cobra dominates the US market.
Michael Roche, author of this particular article, states how arborists like steel cables because they are tried and true, they last a long time, the materials are reasonably priced, and they work. While other arborists like fabric cables because there is no drilling into the tree, no tools are required, installing them is easy to learn, and they work.
There are downfalls to both systems:
* when you use steel cables, you wound the tree, leaving an opening for infection.
* steel cables reduce tree sway and with a reduction in taper the tree becomes weaker.
* polypropylene cables, has the potential for photo-degradation, the material seems to stretch over time, one has to employ routine inspections more often, and some say the material is not as aesthetically pleasing.
The benefits of the Cobra system is that the gear weighs less than a rope and saddle and it's so simple to install, the person estimating the job can install a cable on the spot. This makes a tree company more efficient and only adds to the bottom line. Metal cabling requires tools and materials that weigh so much that a separate tree crew is necessary, preferably with a bucket truck. The Cobra flexes in the wind, that is once it is installed properly and the correct slack is achieved.
For more information on this topic, try to get your hands on the pre-described volume of TCI magazine and turn to page 26.
Ultimately, the final decision is up to the arborist tackling the task, therefore, use the system that you feel most comfortable with. As I mentioned above, both static and dynamic have their benefits and downfalls, but what in this industry doesn't?
Shane Freeman
tshanefreeman
ArboristSite Operative
For Toddppm
I suppose that I should have used proper quotation marks and made a true reference page for my entry, but I thought I was clear at the outset of my entry. My reply was more-less a synopsis of the article found in Feb's TCI magazine. I thought that I would give coydog and others a chance to see to what Michael Roche wrote about. Guess that I'll know better for the future!
Shane Freeman
I suppose that I should have used proper quotation marks and made a true reference page for my entry, but I thought I was clear at the outset of my entry. My reply was more-less a synopsis of the article found in Feb's TCI magazine. I thought that I would give coydog and others a chance to see to what Michael Roche wrote about. Guess that I'll know better for the future!
Shane Freeman
John Paul Sanborn
Above average climber
It is on target. If you have the Cobra in your truck, all you need is sharp Felcoes and a maybe lighter. I've gotten buy without the lighter.
A cobra cable can be installed by just one person in a very short time.
There has been talk of themfalling apart, but everyon that I've done has stayed in. If you do a proer lenghted burry and set the splice by standing or hanging on the cable there is no problem.
As for ros, I dont see the need for it if there is no separation in the union. If it is just a single side crack then maybe the cable will do.
If there is definate separation in of the union then bracing is a must.
A cobra cable can be installed by just one person in a very short time.
There has been talk of themfalling apart, but everyon that I've done has stayed in. If you do a proer lenghted burry and set the splice by standing or hanging on the cable there is no problem.
As for ros, I dont see the need for it if there is no separation in the union. If it is just a single side crack then maybe the cable will do.
If there is definate separation in of the union then bracing is a must.
Shespen
ArboristSite Member
I would suggest that you go with the cobra in this case because the tree is relativly small and green ash has enough folage to hide the cable. Cobras are ugly and I have had to replace a few with steel cable because the client didn't like the look of the cobra. You also have to ask yourself if you are willing to keep a file on every tree that you cable and set a time in the future to go back and check the condition of every cable. I don't think that cobra systems have been around long enough to come up with a verdict as to their longevity.
The bracing factor depends on the crack. If the crack goes all the way thru then I would definately brace it. The cable will keep the stress off the crack in a perpendicular force but what happens when the wind blows? Is the crack on the upwind side of the tree? If so then the wind will open the crack as itblows against the upper branches pushing both sides in the same direction. It would be like hammering a wedge into the crack. This is just one scnario. I'm sure that you can imagine others when you think about the dynamics of mother nature. If in doubt, brace th ???? thing and move on.
Tip: Check with local utility contractors for scrap cabling supplies. They use the same stuff that we use and they use alot of it. Any piece of cable that is too short to go between two poles is scrap to them. Any left overs from a contract job of laying miles of cable is a write off to them. A cases of beer or a bottle of whiskey can get you a couple of years of cable supplies and they are glad that sombody is cleaning up that mess out back.
Steve
The bracing factor depends on the crack. If the crack goes all the way thru then I would definately brace it. The cable will keep the stress off the crack in a perpendicular force but what happens when the wind blows? Is the crack on the upwind side of the tree? If so then the wind will open the crack as itblows against the upper branches pushing both sides in the same direction. It would be like hammering a wedge into the crack. This is just one scnario. I'm sure that you can imagine others when you think about the dynamics of mother nature. If in doubt, brace th ???? thing and move on.
Tip: Check with local utility contractors for scrap cabling supplies. They use the same stuff that we use and they use alot of it. Any piece of cable that is too short to go between two poles is scrap to them. Any left overs from a contract job of laying miles of cable is a write off to them. A cases of beer or a bottle of whiskey can get you a couple of years of cable supplies and they are glad that sombody is cleaning up that mess out back.
Steve
John Paul Sanborn
Above average climber
Any cabling job is a temporary fix, especaly if the tree is young. Once you put a cable in you should periodicly inspect the tree. Your cabling contract and bill should include the recomendations for inspection cycle.
It could be as easy as a walk through visual inspection. Whay would you not want to get an oportunity to walk the property and suggest more work? Have a file in your cabinet for that years cables, inspect aroun 1 year under your warenty then say every three years. Just call ahead to let them know. The leave a note saying "...the system looks good, but we noticed the Norway maple in back could use ______ work." or "...the silver maple has out grown the current system and should have a replacement added higher in the tree. Also the Norway..."
It could be as easy as a walk through visual inspection. Whay would you not want to get an oportunity to walk the property and suggest more work? Have a file in your cabinet for that years cables, inspect aroun 1 year under your warenty then say every three years. Just call ahead to let them know. The leave a note saying "...the system looks good, but we noticed the Norway maple in back could use ______ work." or "...the silver maple has out grown the current system and should have a replacement added higher in the tree. Also the Norway..."
Toddppm
Addicted to ArboristSite
TShane, not trying to be picky, I understood you were quoting the article. I just can't see many Salesman installing a cable while doing an estimate. Not just because they couldn't but the safety factor of working alone
seanlarkin
ArboristSite Guru
I asked Tobe for his comments, as he knowsway more about cabling/cobra than I. His response:
"It will likely require bracing to keep the crack still enough for the tree
to compartmentalize the wound. If it's an old crack there may be no hope in
that. If you install Cobra or steel alone and the spars get a torque effect
going in wind (side to side) the crack might chafe and move a bit without
bracing.
-Good Luck"
Hope that helps.
-Sean
"It will likely require bracing to keep the crack still enough for the tree
to compartmentalize the wound. If it's an old crack there may be no hope in
that. If you install Cobra or steel alone and the spars get a torque effect
going in wind (side to side) the crack might chafe and move a bit without
bracing.
-Good Luck"
Hope that helps.
-Sean
Rob Murphy
ArboristSite Operative
cobra
Here's some cobra pic taken the other day .I like it but it tooo expensive over here ( OZ ) reackon we will mostly stay with steel.
Here's some cobra pic taken the other day .I like it but it tooo expensive over here ( OZ ) reackon we will mostly stay with steel.
Rob Murphy
ArboristSite Operative
Sorry about the truck photo......I am playing around with sending pics... thats if anyone has'nt noticed.
Maybe Sean could use it on the front cover of the new Catalouge
The Sherrill/Vermeer thing is working well for us down here.Gave out about 40 of the old catalouge's at a field day yesterday. Keen to see the new one!!!
Maybe Sean could use it on the front cover of the new Catalouge
The Sherrill/Vermeer thing is working well for us down here.Gave out about 40 of the old catalouge's at a field day yesterday. Keen to see the new one!!!
thanx for replies I will include bracing in my estimate, as well as the option of using steel or Cobra cables It's hard to convince people in farm country to pay the extra dollar(s) for Cobra systems. I have worked with Cobra in the past and love installing them, very tree and tree worker friendly. It would be interesting to invent a bracing system that was easy and non invasive. I suppose the biggest reason I dont like braces is the possibility of decay invading the hole and stripping out the brace. I removed many trees that had old braces hiding inside of them doing nothing but waiting for an unsuspecting saw. I am concerned about the possibility of UV decay in Cobras, I guess we'll all have to wait and see about that one. One idea I've had for cabling is to anchor a steel cable with a Cobra sling, using steel rings for attachment. That would eliminate the shock absorbing effect of Cobra systems but would also eliminate the need to drill holes to anchor a traditional steel cable system. I would be concerned with the friction factor of the attachment of Cobra to cable via steel ring over time. Any thoughts?
Rob Murphy
ArboristSite Operative
Was thinking the same thing the other day. It would be nice to have the noninvasiveness of cobra combined with the security of steel.
Has anyone worked on this ???
Has anyone worked on this ???
John Paul Sanborn
Above average climber
there is a swedish company making a steel to synthetic system. I cannot remember which catalog caries it.
My understanding of current bracing is that it is not the threading that does the holding but the washers. This is whay you do not install the brace without a cable system and install more then one rod.
My understanding of current bracing is that it is not the threading that does the holding but the washers. This is whay you do not install the brace without a cable system and install more then one rod.
Kneejerk Bombas
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I too have seen many threaded rod laying in a pile of rotten wood inside a tree.
The washer does hold the tree together temporarily, but we all know about CODIT, and all the wood will be compartmentalized around the rod and under the washer, therefore subject to rot.
If you must use rod, stack alternating washers and nuts, as far out as you can. Then when the new wood, outside the compartmentalization, is layed down by the tree it has something to hold on to.
Tom Dunlop's idea, and I think a good one, is to pull the top toghether, bolt the crack with rod, go up a short distance and install a steel cable, then go to the top and release the tension and add a cobra.
Does anyone else think the cobra pictured in this thread, is installed too low? Unless that tree is 300' tall, it looks like it's installed at about half way up.
The washer does hold the tree together temporarily, but we all know about CODIT, and all the wood will be compartmentalized around the rod and under the washer, therefore subject to rot.
If you must use rod, stack alternating washers and nuts, as far out as you can. Then when the new wood, outside the compartmentalization, is layed down by the tree it has something to hold on to.
Tom Dunlop's idea, and I think a good one, is to pull the top toghether, bolt the crack with rod, go up a short distance and install a steel cable, then go to the top and release the tension and add a cobra.
Does anyone else think the cobra pictured in this thread, is installed too low? Unless that tree is 300' tall, it looks like it's installed at about half way up.
Rob Murphy
ArboristSite Operative
Mike
Are you talking about my cobra pic? Its in a Euc nicholli,about 3/4 the height of a 30' tree. Some of the smaller Eucs have rapid trunk taper dimunation .Here's another pic of a small Euc (not the same tree) as an example.
Are you talking about my cobra pic? Its in a Euc nicholli,about 3/4 the height of a 30' tree. Some of the smaller Eucs have rapid trunk taper dimunation .Here's another pic of a small Euc (not the same tree) as an example.
what do you mean stack alternating washers and nuts as far as I can? Wouldn't that create quite a protrusion of hardware ( while it might work I'd be concerned about the kids running into it, the place I'd be bracing is about 5' up, right at eyeball level for a big kid, not to mention clumsy adult)
John Paul Sanborn
Above average climber
Picture it getting engulfed by the new wood like eybolts do. More holding power. Since the wall 4 is the strongest the nwe wood growing around it will be least likly to decay.
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