i would agree there mark, it is difficult to generlize, every situation is different. i'm glad we agree on lightening the load and i agree that this does not mean taking a whole limb off or reducing it by 50%. I think you can find a balance between weight and energy stores.
Cabling
- Thread starter Mark Chisholm
- Start date
- Location
- Home of the New Jersey Devils
I would also agree with you in regards to drawing a line between what is logical in repairing and what must be removed. Some flaws will never be deemed comfortable enough to no longer be dangerous. I guess it comes down to proper risk acessment.
Another obvious factor is how improtant the tree is to the owner or community. I've placed rods in split mulberries and split catalpa trees that I would have preferred to just remove. But, if the client really wants to preserve a tree for as long as possible, all we can do is advise and then try to satisfy their goals.
Another obvious factor is how improtant the tree is to the owner or community. I've placed rods in split mulberries and split catalpa trees that I would have preferred to just remove. But, if the client really wants to preserve a tree for as long as possible, all we can do is advise and then try to satisfy their goals.
- Location
- S.E. Wisconsin
[ QUOTE ]
Thanks for the feedback Mike. Here's another question now, what if the tree you are cabling has an old, tight cable in it and you want to replace it. Can you use synthetics here?
[/ QUOTE ]
Recently, I have been installing several of what Tom D. calls hybrid tree support systems. It's basically metal hardware down low, and synthetic up high. The metal is used mainly to isolate the crack from moving so it can start to grow back together, and the synthetic rope prevents the crotch from spreading to the point where the lower hardware is over stressed and fails.
So to try to answer your question, my first inclination would be to install a Cobra at the proper height and leave the old cable. My thinking is the Cora would prevent the upper part of the tree from spreading wide enough to overload the old cable.
Then you need to ask yourself why the first cable was installed. Was it because of a crack or just preventative? If it was because of a crack, removing the cable could lead to re-cracking.
If it was preventative, you need to think about how long it was in the tree, isolating movement. If it has been tight for a long time, the tree may have become dependant on its support, another reason to leave it. I recently told a story about cutting out a dead tree that was supporting a live one, and the live one failed because it became dependent on the support.
To tell if the old cable is too tight, I guess I'd go above it and pull the two haves together and see how much presure is on it. If that load is so high it might cause cable failure, you need to do something about it, not just add a Cobra above it.
I do not prescribe to the idea of crown reduction as a way to make a mature tree stronger. Trees are not just structures, they are living biological orginisms that have more reactions to cutting than we may ever understand.
If you do crown reductionon a mature tree, it is my opinion that you are simply starting the removal process. But that's another subject. /forum/images/graemlins/crazy.gif
Thanks for the feedback Mike. Here's another question now, what if the tree you are cabling has an old, tight cable in it and you want to replace it. Can you use synthetics here?
[/ QUOTE ]
Recently, I have been installing several of what Tom D. calls hybrid tree support systems. It's basically metal hardware down low, and synthetic up high. The metal is used mainly to isolate the crack from moving so it can start to grow back together, and the synthetic rope prevents the crotch from spreading to the point where the lower hardware is over stressed and fails.
So to try to answer your question, my first inclination would be to install a Cobra at the proper height and leave the old cable. My thinking is the Cora would prevent the upper part of the tree from spreading wide enough to overload the old cable.
Then you need to ask yourself why the first cable was installed. Was it because of a crack or just preventative? If it was because of a crack, removing the cable could lead to re-cracking.
If it was preventative, you need to think about how long it was in the tree, isolating movement. If it has been tight for a long time, the tree may have become dependant on its support, another reason to leave it. I recently told a story about cutting out a dead tree that was supporting a live one, and the live one failed because it became dependent on the support.
To tell if the old cable is too tight, I guess I'd go above it and pull the two haves together and see how much presure is on it. If that load is so high it might cause cable failure, you need to do something about it, not just add a Cobra above it.
I do not prescribe to the idea of crown reduction as a way to make a mature tree stronger. Trees are not just structures, they are living biological orginisms that have more reactions to cutting than we may ever understand.
If you do crown reductionon a mature tree, it is my opinion that you are simply starting the removal process. But that's another subject. /forum/images/graemlins/crazy.gif
True, politics start to play in the game, i think this will always be a controvercial topic. As what you say, correct risk acessment and informing the client of the potentional hazards are important.
We can never please everyone
We can never please everyone
[ QUOTE ]
I do not prescribe to the idea of crown reduction as a way to make a mature tree stronger. Trees are not just structures, they are living biological orginisms that have more reactions to cutting than we may ever understand.
If you do crown reductionon a mature tree, it is my opinion that you are simply starting the removal process. But that's another subject. /forum/images/graemlins/crazy.gif
[/ QUOTE ]
Mike,
You're right, it's another topic, but when i thnik of let's say an old english oak that has been around for hounders of years where there has been no human intervention, nature (wind) reduces these trees when they get to heavy, they create new crowns, and they are still standing. I agree reducing does not make a mature tree stronger but it does reduce machanical force on forlks.
Hey, maybe you're right, maybe we will never understand the true dynamics of a tree, it is a very complex orginism.
I do not prescribe to the idea of crown reduction as a way to make a mature tree stronger. Trees are not just structures, they are living biological orginisms that have more reactions to cutting than we may ever understand.
If you do crown reductionon a mature tree, it is my opinion that you are simply starting the removal process. But that's another subject. /forum/images/graemlins/crazy.gif
[/ QUOTE ]
Mike,
You're right, it's another topic, but when i thnik of let's say an old english oak that has been around for hounders of years where there has been no human intervention, nature (wind) reduces these trees when they get to heavy, they create new crowns, and they are still standing. I agree reducing does not make a mature tree stronger but it does reduce machanical force on forlks.
Hey, maybe you're right, maybe we will never understand the true dynamics of a tree, it is a very complex orginism.
A few weeks ago in Belgum they did some interesting pulling tests. They pulled a bunch of leaders out of trees (inverted bark forlks, not sure what you call these in english??)using the same softwear they use for the tree stability pulling tests.
more or less simulating at what wind force a leader would break out. Once they have processed the data i'll post it.
more or less simulating at what wind force a leader would break out. Once they have processed the data i'll post it.
- Location
- S.E. Wisconsin
[ QUOTE ]
I agree reducing does not make a mature tree stronger but it does reduce machanical force on forlks.
[/ QUOTE ]
Yes, but only at that exact point in time. In years to come, many detrimental biological things may have happened. It lost a percentage of it's ability to take up energy (leaves), it used it's photosythates to repair injuries (cuts), it changed growth patterns trying to replace lost foliage (more energy use), it devoted less energy to adding new wood, it added a smaller percentage of reaction wood to weak areas of the tree because they became lighter (lack of movement signals tree to add less wood), it abandoned a corresponding percentage of roots creating new areas for infections and needed compartmentalizing (more energy use), and other things too many to mention happen, both proven with science and theorized.
I agree reducing does not make a mature tree stronger but it does reduce machanical force on forlks.
[/ QUOTE ]
Yes, but only at that exact point in time. In years to come, many detrimental biological things may have happened. It lost a percentage of it's ability to take up energy (leaves), it used it's photosythates to repair injuries (cuts), it changed growth patterns trying to replace lost foliage (more energy use), it devoted less energy to adding new wood, it added a smaller percentage of reaction wood to weak areas of the tree because they became lighter (lack of movement signals tree to add less wood), it abandoned a corresponding percentage of roots creating new areas for infections and needed compartmentalizing (more energy use), and other things too many to mention happen, both proven with science and theorized.
True, removing to many leaves (food/light factories)will reduce the trees ability to make reaction wood. I agree it costs energy for the tree to recover from these sorts of actions...... but what do you do?? is there not a balance?
[censored], now i'm stumped /forum/images/graemlins/smile.gif /forum/images/graemlins/confused.gif
[censored], now i'm stumped /forum/images/graemlins/smile.gif /forum/images/graemlins/confused.gif
- Location
- Bloomington, Indiana
[ QUOTE ]
If you do crown reductionon a mature tree, it is my opinion that you are simply starting the removal process.
[/ QUOTE ]
Very good point Mike. But, that point could be used either to discourage unneeeded crown reduction in a healthy, stable tree; or to validate crown reduction in a tree with a structural weakness.
Case by case as others said.
[ QUOTE ]
But that's another subject
[/ QUOTE ]
Right there too.
Mahk
If you do crown reductionon a mature tree, it is my opinion that you are simply starting the removal process.
[/ QUOTE ]
Very good point Mike. But, that point could be used either to discourage unneeeded crown reduction in a healthy, stable tree; or to validate crown reduction in a tree with a structural weakness.
Case by case as others said.
[ QUOTE ]
But that's another subject
[/ QUOTE ]
Right there too.
Mahk
- Location
- Bloomington, Indiana
[ QUOTE ]
A few weeks ago in Belgum they did some interesting pulling tests. They pulled a bunch of leaders out of trees (inverted bark forlks, not sure what you call these in english??)using the same softwear they use for the tree stability pulling tests.
more or less simulating at what wind force a leader would break out. Once they have processed the data i'll post it.
[/ QUOTE ]
Please do Jelte.
There is an article in an upcoming issue of Arborist News magazine that looks at a similar topic. The authors pulled apart a bunch of branch crotches and examined them for structure and how that relates to strength.
It will be interesting to compare the two studies.
Mahk
A few weeks ago in Belgum they did some interesting pulling tests. They pulled a bunch of leaders out of trees (inverted bark forlks, not sure what you call these in english??)using the same softwear they use for the tree stability pulling tests.
more or less simulating at what wind force a leader would break out. Once they have processed the data i'll post it.
[/ QUOTE ]
Please do Jelte.
There is an article in an upcoming issue of Arborist News magazine that looks at a similar topic. The authors pulled apart a bunch of branch crotches and examined them for structure and how that relates to strength.
It will be interesting to compare the two studies.
Mahk
- Location
- Retired in Minneapolis
It's going to take some time but I will dig out pictures of a couple of hybrid support systems I've built. All my goods are stacked away in a storage container until I buy a house. In due time I'll have them at hand.
No matter what we use to stablize trees we need to look closely at how trees have grown. They're three dimensional beings. They need to move in all dimensions. For the most part, steel cables don't allow movement in 3D. If the cables were left a little slack they could though.
I've sen more poorly installed support systems than proper. When I was in Germany a few years ago there were some Cobra installs at Rothenberg that were not only in the wrong place in the trees, they were ugly and sloppy. Big droopy lines and long tails unravling from the splices. There was a webbing and rope install at [sp?] Neuschwanstein [the "Disney" castle] that was just as ugly and ineffective.
If the tree has cracked, I'll put in a temporary support and do some pruning. Fix the mechanical part of the tree first. Then go and do the support. More times than not I would put in a hybrid. Bolt the trunk, maybe put a rod above the split but I've also put short cables low in the tree. Then put a rope-based system high. Let the trunk move more as one unit and let the limbs move in 3D.
Does anyone else do a double nut system when bolting or using eye bolts? Washer against tree, nut, washer and nut. That way the tree can grow around the second washer and have more "grab" similar to using screws instead of nails.
I'll be interseted to read the results of the pull tests. Wulkie admonished us a while ago to be careful about how we use the data. It is rare that trees fail from a pull at a point. They're 3D and the forces and loads are spread around. It would be really cool to get the guys from the TV show Mythbusters to setup a test for this. They used a jet engine mounted on a stand to blow away a car. They could do the same thing here. The engine could be moved around and the load applied in different directions. They could also set the throttle up to pulse. Since most winds aren't steady, the tree would shift and relax. I wonder what effect this pulsing may have on failure. Look at what the Cordage Institute tells us about ropes. Load a rope to half it's breaking strength too many times in a row without letting it relax has the potential for failure. More than going to 90% and then leaving the rope to relax.
We need to know more about trees. these failure tests will give us bits and snips of insights.
Tom
PS I hope that you've all made up. The nasty barbs back and forth really detract from the feeling that has become the norm at TB.
No matter what we use to stablize trees we need to look closely at how trees have grown. They're three dimensional beings. They need to move in all dimensions. For the most part, steel cables don't allow movement in 3D. If the cables were left a little slack they could though.
I've sen more poorly installed support systems than proper. When I was in Germany a few years ago there were some Cobra installs at Rothenberg that were not only in the wrong place in the trees, they were ugly and sloppy. Big droopy lines and long tails unravling from the splices. There was a webbing and rope install at [sp?] Neuschwanstein [the "Disney" castle] that was just as ugly and ineffective.
If the tree has cracked, I'll put in a temporary support and do some pruning. Fix the mechanical part of the tree first. Then go and do the support. More times than not I would put in a hybrid. Bolt the trunk, maybe put a rod above the split but I've also put short cables low in the tree. Then put a rope-based system high. Let the trunk move more as one unit and let the limbs move in 3D.
Does anyone else do a double nut system when bolting or using eye bolts? Washer against tree, nut, washer and nut. That way the tree can grow around the second washer and have more "grab" similar to using screws instead of nails.
I'll be interseted to read the results of the pull tests. Wulkie admonished us a while ago to be careful about how we use the data. It is rare that trees fail from a pull at a point. They're 3D and the forces and loads are spread around. It would be really cool to get the guys from the TV show Mythbusters to setup a test for this. They used a jet engine mounted on a stand to blow away a car. They could do the same thing here. The engine could be moved around and the load applied in different directions. They could also set the throttle up to pulse. Since most winds aren't steady, the tree would shift and relax. I wonder what effect this pulsing may have on failure. Look at what the Cordage Institute tells us about ropes. Load a rope to half it's breaking strength too many times in a row without letting it relax has the potential for failure. More than going to 90% and then leaving the rope to relax.
We need to know more about trees. these failure tests will give us bits and snips of insights.
Tom
PS I hope that you've all made up. The nasty barbs back and forth really detract from the feeling that has become the norm at TB.
Everyone always talks about steel cables not allowing any give to the trunks/limbs they support, therefor the tree doesn't continue to build up diameter strength.
I assumed the same thing till just the other day.
With all this cable talk;
that day while we had those strong winds (all day); I went to a big silver maple we cabled 2 years ago to watch how it responded to the gusts.
three different leads had been cabled. When the strong gusts blew, the leads would all move a lot, but they all would move in the same direction so it didn't matter that it was steel cable. Think about it, the wind gusts blow in one direction at a time and therefor all the leads would bend in the same direction. The cable was just going with the flow.
Now, I'm sure synthetic would allow for much more movement, especially if the leads were very different in diameters and therefor very different in movement.
But I'm just stating what I saw cause I was suprized about how much movement a tree can still move with steel cables.
It was interresting to watch. I filmed it too.
Next time you have a strong windy day, go to a cabled tree and watch it for a while if you haven't done so yet. Very interresting.
P.S. You are right that the nasty barbs back and forth really detract from the feeling that has become the norm at TB. And I'm sorry for taking up space on this topic going back and forth. Next time maybe I should just write a personal message if I have a problem with something and only post "on-topic" talk on the public board. My appologies.
I assumed the same thing till just the other day.
With all this cable talk;
that day while we had those strong winds (all day); I went to a big silver maple we cabled 2 years ago to watch how it responded to the gusts.
three different leads had been cabled. When the strong gusts blew, the leads would all move a lot, but they all would move in the same direction so it didn't matter that it was steel cable. Think about it, the wind gusts blow in one direction at a time and therefor all the leads would bend in the same direction. The cable was just going with the flow.
Now, I'm sure synthetic would allow for much more movement, especially if the leads were very different in diameters and therefor very different in movement.
But I'm just stating what I saw cause I was suprized about how much movement a tree can still move with steel cables.
It was interresting to watch. I filmed it too.
Next time you have a strong windy day, go to a cabled tree and watch it for a while if you haven't done so yet. Very interresting.
P.S. You are right that the nasty barbs back and forth really detract from the feeling that has become the norm at TB. And I'm sorry for taking up space on this topic going back and forth. Next time maybe I should just write a personal message if I have a problem with something and only post "on-topic" talk on the public board. My appologies.
Norm_Hall
New member
- Location
- Wauconda, (Chicago),IL,USA
I have pruned trees that steel cables were installed in 35 years ago and the trees are doing fine. Not that I'm against change, I would like to see alot more info on synthetic systems before I buy into it. Do animals eat it or gnaw on it (squirrels, raccoons, opposum, birds)? Do the UV rays degrade it? How long before it starts "choking" the tree? It appears that this type of system needs to be installed in a crotch. What if a crotch isn't available?
Those of you that are using synthetics, what have you found and how long have you been using them? Thanks!
Those of you that are using synthetics, what have you found and how long have you been using them? Thanks!
- Location
- Bucks Co. P.A.
I've seen plenty of leaders broken out of main crotches and still hanging from their steel support. Any failures I've seen have had some sort of bad install or defect from natural effects that caused failure of the actual cable or hardware.
It seems that long term results are recently being trusted for steel cables and not enough long term for synthetics to have a wide acceptance. I like synthetics just for the fact of non invasive. In the short term. Like Norm said, what about girdling in long term? Synthetics will evolve and we'll get a good product soon enough, I hope. I hate drilling a tree, but something has to be done.
Later
It seems that long term results are recently being trusted for steel cables and not enough long term for synthetics to have a wide acceptance. I like synthetics just for the fact of non invasive. In the short term. Like Norm said, what about girdling in long term? Synthetics will evolve and we'll get a good product soon enough, I hope. I hate drilling a tree, but something has to be done.
Later
- Location
- S.E. Wisconsin
What failures do you see with the "invasive drilling"?
I ask because I have yet to see a cable failure caused by decay at the cabling point.
With proper installations, it's time that causes problems, because down the road the tree grows to high and puts too much leverage on the cable.
I ask because I have yet to see a cable failure caused by decay at the cabling point.
With proper installations, it's time that causes problems, because down the road the tree grows to high and puts too much leverage on the cable.
- Location
- Austin, TX
I have pruned trees that had were filled with cement 50 years ago. Does this make an argument for cement?? /forum/images/graemlins/pokinit.gif
I have removed old dynamic cables - they don't girdle and crotches are not needed.
We need to start with a clear set of definitions or categories. Here are a few off the top of my head.
1. Cabling to prevent failure
2. Cabling after failure - a crack, split, etc.
3.psychosomatic cabling /forum/images/graemlins/not4me.gif - cabling for clients that need a psychiatrist more than an arborist. More chance of the moon hitting their house than said tree limb.
Dynamic is best for senarios 1 and 3. Simply because it is
Better
Quicker to install
Cheaper
In senario 1 metal can actually cause failure via karate
In all senarios cables, metal or dynamic need to be inspected regularly or adjusted. Since both need to be inspected regularly, just replace the dynamic if you think it is weathering. /forum/images/graemlins/yup.gif
If continuum of care is in question, the idea of leaving uninspected metal cables in trees should raise some red flags just the same as leaving uninspected dynamic cables.
/forum/images/graemlins/wavzing.gif
I have removed old dynamic cables - they don't girdle and crotches are not needed.
We need to start with a clear set of definitions or categories. Here are a few off the top of my head.
1. Cabling to prevent failure
2. Cabling after failure - a crack, split, etc.
3.psychosomatic cabling /forum/images/graemlins/not4me.gif - cabling for clients that need a psychiatrist more than an arborist. More chance of the moon hitting their house than said tree limb.
Dynamic is best for senarios 1 and 3. Simply because it is
Better
Quicker to install
Cheaper
In senario 1 metal can actually cause failure via karate
In all senarios cables, metal or dynamic need to be inspected regularly or adjusted. Since both need to be inspected regularly, just replace the dynamic if you think it is weathering. /forum/images/graemlins/yup.gif
If continuum of care is in question, the idea of leaving uninspected metal cables in trees should raise some red flags just the same as leaving uninspected dynamic cables.
/forum/images/graemlins/wavzing.gif
Attachments
- Location
- Home of the New Jersey Devils
Thanks for the feedback Nathan. Do you (or Jelte) or anyone else for that matter, have any photos of some dynamic systems that you've installed?
What system are you using? Cobra?
This has been a good thread. Let's keep on discussing it.
What system are you using? Cobra?
This has been a good thread. Let's keep on discussing it.
Mangoes
Participating member
- Location
- Greater Toronto Area
Are you using lags or rod? Stainless or galvanized? A friend of mine had some cabling hardware destuctively tested a few years ago. 5/8 stainless threaded rod with galv. amon eyes on both ends and pulled, if memory serves they failed (bent the eyes) 40000-50000lbs range. 1/2 stainless threaded rod with galv. amon eyes failed (bent the eyes) in the 20000-30000 range. I'll get him to verify the numbers. The amazing part was the company had been spending the money and time for years putting 5/8 systems in trees. All with a four wrap, same direction, tight wrap, service style. As it turns out when the serviced cable was destructively tested it failed WAY less than the 1/2" hardware. Which is great, less money, less time cutting, etc.
- Location
- Austin, TX
[ QUOTE ]
Nathan,
I sure don't find Cobra any cheaper. At over $700.00 CAN for a basic kit, I find it outragously expensive!
[/ QUOTE ]
Who mentioned Cobra /forum/images/graemlins/confused.gif
We are using this stuff http://www.freeworker.de/store/pd549426322.htm?defaultVariants=search0_EQ_20%20kN_AND_{EOL}&categoryId=10
and the stuff with the 5% stretch
Will be installing more later this week and I will be sure to get some pics
Off to work /forum/images/graemlins/vroam.gif
Nathan,
I sure don't find Cobra any cheaper. At over $700.00 CAN for a basic kit, I find it outragously expensive!
[/ QUOTE ]
Who mentioned Cobra /forum/images/graemlins/confused.gif
We are using this stuff http://www.freeworker.de/store/pd549426322.htm?defaultVariants=search0_EQ_20%20kN_AND_{EOL}&categoryId=10
and the stuff with the 5% stretch
Will be installing more later this week and I will be sure to get some pics
Off to work /forum/images/graemlins/vroam.gif
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