Tree-to-Ground Guying

quercus · 3rd March 2008, 08:31 AM

sorry 'bout the touchy post... wasn't for you actually... But no worries.

Squirrels out here seem to leave cobra alone, so I've never had an encounter with a cable that had bite marks or ripped parts in it. I've seen them run over the cables though, but I don't think that'll harm them.
Do you really think that will be necessary? You could try a large diameter garden hose, but the splices won't fit in it.

bigshea13 · 3rd March 2008, 05:12 PM

cut the hose in half put it around the cable and splice and then tape it back togather.

TreeSpecialist · 19th March 2008, 05:09 AM

Tree to Ground Guying is possible but should be designed by a consulting structural engineer to minimize your liability.

First you should probably advise (in writing) the removal of the tree and acknowledge receipt of such advice. You might also get the homeowner to sign something to waive any of your responsibility should the tree fail.

Tree to Ground Anchor should weigh as much as the tree (engineer's CYA - you can guesstimate the weight - use Sherrill's chart). This involves drilling and filling a large hole with a great deal of concrete and steel. The cables would then be attached to the anchor.

From the pictures, you should use at least 3 anchors to do it right.

The cost could run as much as $2500 per anchor.

Picture attaches is an oak I did 2 years ago where 70% of the roots were severed on a live oak no one wanted to loose.

TreeSpecialist · 19th March 2008, 05:10 AM

Photo didn't upload......

Treelore · 21st March 2008, 09:04 AM

Why on earth would the guying need to rate as much as the weight of the tree if you don't expect the tree to fail from the base?? I feel some people are missing we need to hang the picture not the wall.

quercus · 21st March 2008, 11:06 PM

Quote:

Originally Posted by TreeSpecialist

Tree to Ground Guying is possible but should be designed by a consulting structural engineer to minimize your liability.

First you should probably advise (in writing) the removal of the tree and acknowledge receipt of such advice. You might also get the homeowner to sign something to waive any of your responsibility should the tree fail.

Tree to Ground Anchor should weigh as much as the tree (engineer's CYA - you can guesstimate the weight - use Sherrill's chart). This involves drilling and filling a large hole with a great deal of concrete and steel. The cables would then be attached to the anchor.

From the pictures, you should use at least 3 anchors to do it right.

The cost could run as much as $2500 per anchor.

Picture attaches is an oak I did 2 years ago where 70% of the roots were severed on a live oak no one wanted to loose.

doing a good assessment on that tree is pretty difficult because we need to see a lot more of the surroundings. Judging on this picture alone, I'd say that the anchor point is at least 45 degrees off the position where it should be.
Do realize that it could even be up to 120 degrees if I see more pics of the surroundings. Tree cabling should not be done by structural engineers, it should be done by certified arbs. Don't do an assessment on cabling when you don't feel like taking responsability for it. I'll take responsability gladly for everything I do concerning trees. That's what sets us apart as tree-specialists.

Treelore...

I'd like you to asses a tree for me I've been following for the past 6 years.
Does this tree need bracing? Yes or no? Based on what?
What I want from you is actual figures on how you should install bracing and what type of bracing you'd use and why. Where would you install the bracing and why?
What sort of tools would you use for the assessment and based on what facts?
There is no way you are gonne get a license to take it down, but why would you want to think about taking it down in the first place?
Is there any reason why you would investigate further?

facts are...

Fagus Sylvatica DBH 108 cm's
Height 26 meters.
leaning angle: exactly vertical... 90 degrees.
Crown spread: 12 meters with a 50/50 spread on each side.

Location: In the middle of a park. right next to a walkway where there is frequent traffic of groups up to 300 people whom are 95% formed out of elderly or sick people. These large groups do tend to visit only from may up to august or september. Also other protected trees and historically protected constructions in the possible target area. On the opposite side is a trench about 10 meters wide and 6 meters deep, but do keep in mind that this trench has been there for the last 450 years and no excavations where done recently. The trench has a 60 to 75 degree slope on the sides and the soil is not compacted and allows proper penetration of air and moisture. The walkway has been there for over 150 years without restoration and it does allow penetration of air and moisture. There is no heavy traffic allowed in the vicinity of the tree other then a small landscapers tractor (wich has lawn tires) of about 800 kg's wich rides on the walkway at least 10 times a year. So there was never any severe soil compaction.
Surrounded by similar trees of the same height and higher so windfall is not likely since the tree is protected from it.
Standing tall with a gaping hole in it for the last 30 years. The cavity does exceed VTA standards of the 30% sound wood rule. Other cavity's have been measured and are well within 30% loss of sound wood of the diameter
No fruiting bodies whatsoever to be seen. Nore are there (except for one Quercus Rubra) on any of the surrounding trees within a 250 meter radius. (I know because I've checked them all...)
The tree appears to be healthy and there's normal foliage and seed production in the season. No early leaf-loss and the crown is free of structural damage or structural hazards. No pruning took place in the last 25 years. Other then the hole on a height of about 10 meters up the stem appears to be intact. Roots located under the walkway have been exposed very carefully by me about two years ago and they show no severe damage or decay. No roots have been cut in the last 50 years. Can't say anything about before that period because no-one seems to remember. Here are some pics of the assessment I've done....As soon as I have your professional oppinion, I'll give you mine....

Treelore · 23rd March 2008, 04:15 PM

Difficult to say with the info given Q. Few more photos would be helpful. Would be reluctant to tree to ground cable in this situation as it would place excessive forces on cavities that is unnecessary. Is it Municipal? Depending on budget I would be inclined to recommend that you oversee the construction of a steel reinforced covered walkway for the length of the target zone with a cage like roof so people may still enjoy the forest outlook but allow the trees around to fall apart at will.

treeseer · 23rd March 2008, 05:06 PM

Quote:

Originally Posted by quercus

Tree cabling should not be done by structural engineers, it should be done by certified arbs. Don't do an assessment on cabling when you don't feel like taking responsability for it. I'll take responsability gladly for everything I do concerning trees. That's what sets us apart as tree-specialists.

Well spoken. I'll post more pics of the oak when it leafs out. Owners are talking about budget now so I will reassess briefly in a month or so. If they cry poor I may just sell them a light reduction in August.

re the beech, well documented! From all I see, the only sure thing to do is chisel away the dead wood that inhibits closure by callus. To reduce the risk to the path, maybe a fall-arrest cable attached to a tree away from the path.

I don't think the old folks would like walking through a steel cage very much...

Treelore · 23rd March 2008, 05:24 PM

There is nothing unusual about having covered walkways in areas such as this the cage idea was so that you could still see rather than an iron roof. None of the other trees within the area seem large enough to brace to and why would you invade other sound trees if you could solve the problem by not touching the tree at all. Who cares what the old people think about it...Do you care about being guided under trellising when they are building a building within a city. I am not adamant on this suggestion merely saying that from info supplied looks to me to be best outcome.

Ekka · 23rd March 2008, 06:29 PM

Quote:

Originally Posted by Treelore

Difficult to say with the info given Q. Few more photos would be helpful. Would be reluctant to tree to ground cable in this situation as it would place excessive forces on cavities that is unnecessary. Is it Municipal? Depending on budget I would be inclined to recommend that you oversee the construction of a steel reinforced covered walkway for the length of the target zone with a cage like roof so people may still enjoy the forest outlook but allow the trees around to fall apart at will.

It's an option, but it costs, aesthetics etc?

Even removal is an option, with many other trees around will it be noticed that much?

Fall arrest, to what? Like having the pulley below the section being cut out when taking the top out it will only come down, from wound to ground is less than the length of the failed piece.

Prune and reduce, will impact the longivity and can exacerbate any decline tree is having already, but cost it. Likely under QTRA that the odds of failure would be in adverse weather and frame walking/wheel chair toddling beneath would cease in such weather.

Sign and paint out hazard area on walkway indicating no-one to sight see or loiter in vicinity due to possible falling limbs, combination prune also, soil care/mulch etc.

Like New Farm park, after all the "experts" made a buck the trees still do as they want. Your options are.

1/ Do nothing
2/ Prune
3/ Remove.

Here's what the fantastic park looks like now.

quercus · 24th March 2008, 02:30 AM

Quote:

Originally Posted by Treelore

Difficult to say with the info given Q. Few more photos would be helpful. Would be reluctant to tree to ground cable in this situation as it would place excessive forces on cavities that is unnecessary. Is it Municipal? Depending on budget I would be inclined to recommend that you oversee the construction of a steel reinforced covered walkway for the length of the target zone with a cage like roof so people may still enjoy the forest outlook but allow the trees around to fall apart at will.

What more info do you need Treelore? Absolutely everything about the tree and it's surroundings have been mentioned, if not shown in the pictures...

What kind of "cage" do you suggest? What dimensions are we talking about here? You should be able to calculate the weight and impact force on a free fall with the details I've given. Above all... What would you calculate? Impact of the section above the structural defect? Or would you take the whole tree into account? What form must this steel structure have to take on these kinds of forces? And what sort of beams are necessary to build such a construction?

Do you see any reason why there's further investigation needed? What tools would be needed for such further investigation?

What do you think of deflective cabling? That's cabling wich is meant to guide the tree to a good location in the event of failure.

What do you think if I say we cabled this tree using a non- invasive spider-legged type anchoring position with a total of 32 metric tonne cobra guidance cables (2 double cables of 8tonne each)? Do you think, considering the weight calculation and sheer dimensions of the tree, that I am way off the mark again?
When I did the calculation and the assessment for treeseer on the oak, you were able to tell us that my calculation was way off the mark, with a lot less info. At this point you should be able to tell us the same considering the info you have, wich is way more then what you had on the oak.

Ekka · 24th March 2008, 02:37 AM

I think that's a bit over the top but I dont know anything about those trees or your area.

If it were a gum trees etc I'd know real good what it would do.

Good idea though. It's reasonably sheltered too isn't it?

Sean Freeman · 24th March 2008, 03:06 AM

Personally I would say doing any more than continuing with the documented monitoring is over kill based on the occupation rates you've given us...but then thats just me, mind I've got some great pics of a cobra set up to achieve exactly what you're talking about Q.

Note that in this case the relationship between targets and the part likely to fail do justify action.

Its a large Lophostemon confertus with a very nasty injury at the base, more of a concern however is the crack evident running up between the two stems (red arrows)

A wider view portion of the canopy affected shown in yellow bit deceptive actually about 30% not 50%.

Cobra cabling to redirect in the event of failure

Direction of redirected faliure...yes the park owner still hasn't followed advice to close the camping site beneath the tree!!!

Treelore · 24th March 2008, 04:34 AM

Treeser was able to give us a photo of the tree and all of its surrounds. you are in a forest situation and it is difficult at best to get the lay of the land. I resent being questioned about mt ideas of what should be done especially over an internet forum. I am not there Quercus. Your photos don't give me the details that I require should I be onsite. Your methodologies and calculations are yours and you are your own business.... do as you choose. I have no idea if other larger stronger trees are around... I can't be sure you have seen all the things I would see or others may. You cannot in words explain to me all of the parameters involved with this tree so I feel as though I have touched it. Don't dare belittle me with your doings. I suggested an outcome...fair in my judgement based on your few meagre shots of your glove and a path and a tree cavity. If you think you know what to do .....do it. Don't bring me in to an argument because you feel a little hard done by my suggestions earlier about a totally different situation. I haven't seen that one either and may be way off the mark. However the photos gave a clearer view of what was at stake.

TreeSpecialist · 24th March 2008, 06:32 AM

[quote=quercus;25687]doing a good assessment on that tree is pretty difficult because we need to see a lot more of the surroundings. Judging on this picture alone, I'd say that the anchor point is at least 45 degrees off the position where it should be.

Like most situations when cabling is needed, there wasn't a good place to cable the tree back to. Located on a 45º slope, and less than 4 feet off the property line to the east, the roots had been removed on the north, west, and south sides of the tree.

Target? Any one of 12 condominiums which sell for 1.2 to 2.5 million dollars each.

My original recommendation was to remove the tree. Contractor/Owner and City Arborist said save it. With that kind of liability, the structural engineer was brought in.

The location of the two ground anchors should have been at least 45º to the east. The best possible location - due east - was on the adjacent property and not available.

3rd March 2008, 08:31 AM	#51 (permalink)
quercus Mature tree Join Date: Nov 2007 Location: belgium Posts: 428	Re: Tree-to-Ground Guying sorry 'bout the touchy post... wasn't for you actually... But no worries. Squirrels out here seem to leave cobra alone, so I've never had an encounter with a cable that had bite marks or ripped parts in it. I've seen them run over the cables though, but I don't think that'll harm them. Do you really think that will be necessary? You could try a large diameter garden hose, but the splices won't fit in it.

3rd March 2008, 05:12 PM	#52 (permalink)
bigshea13 Mature tree Join Date: Nov 2007 Location: hiding Posts: 378	Re: Tree-to-Ground Guying cut the hose in half put it around the cable and splice and then tape it back togather.

19th March 2008, 05:09 AM	#53 (permalink)
TreeSpecialist Semi-mature vigorous tree Join Date: Mar 2008 Location: Austin, Texas Posts: 122	Re: Tree-to-Ground Guying Tree to Ground Guying is possible but should be designed by a consulting structural engineer to minimize your liability. First you should probably advise (in writing) the removal of the tree and acknowledge receipt of such advice. You might also get the homeowner to sign something to waive any of your responsibility should the tree fail. Tree to Ground Anchor should weigh as much as the tree (engineer's CYA - you can guesstimate the weight - use Sherrill's chart). This involves drilling and filling a large hole with a great deal of concrete and steel. The cables would then be attached to the anchor. From the pictures, you should use at least 3 anchors to do it right. The cost could run as much as $2500 per anchor. Picture attaches is an oak I did 2 years ago where 70% of the roots were severed on a live oak no one wanted to loose.

21st March 2008, 09:04 AM	#55 (permalink)
Treelore Banned Join Date: Feb 2008 Location: Brisbane Posts: 112	Re: Tree-to-Ground Guying Why on earth would the guying need to rate as much as the weight of the tree if you don't expect the tree to fail from the base?? I feel some people are missing we need to hang the picture not the wall.

23rd March 2008, 04:15 PM	#57 (permalink)
Treelore Banned Join Date: Feb 2008 Location: Brisbane Posts: 112	Re: Tree-to-Ground Guying Difficult to say with the info given Q. Few more photos would be helpful. Would be reluctant to tree to ground cable in this situation as it would place excessive forces on cavities that is unnecessary. Is it Municipal? Depending on budget I would be inclined to recommend that you oversee the construction of a steel reinforced covered walkway for the length of the target zone with a cage like roof so people may still enjoy the forest outlook but allow the trees around to fall apart at will.

23rd March 2008, 05:24 PM	#59 (permalink)
Treelore Banned Join Date: Feb 2008 Location: Brisbane Posts: 112	Re: Tree-to-Ground Guying There is nothing unusual about having covered walkways in areas such as this the cage idea was so that you could still see rather than an iron roof. None of the other trees within the area seem large enough to brace to and why would you invade other sound trees if you could solve the problem by not touching the tree at all. Who cares what the old people think about it...Do you care about being guided under trellising when they are building a building within a city. I am not adamant on this suggestion merely saying that from info supplied looks to me to be best outcome.

24th March 2008, 02:37 AM	#62 (permalink)
Ekka Eric Frei Administrator - Brisbane L5 (Dip) Hort Cert III Arb + some Join Date: Jan 2007 Location: Brisbane Posts: 6,932	Re: Tree-to-Ground Guying I think that's a bit over the top but I dont know anything about those trees or your area. If it were a gum trees etc I'd know real good what it would do. Good idea though. It's reasonably sheltered too isn't it? __________________ Remember to use the "search" function, if you have answers/questions post them so everyone can benefit. Free Tree and Green Industry Link Directory Qualified Brisbane Tree Lopping \| Stump Grinding and Stump Removal Brisbane Brisbane Tree Care, Consultations, Developer, Tree and Arborist Reports Forum Sponsors

24th March 2008, 04:34 AM	#64 (permalink)
Treelore Banned Join Date: Feb 2008 Location: Brisbane Posts: 112	Re: Tree-to-Ground Guying Treeser was able to give us a photo of the tree and all of its surrounds. you are in a forest situation and it is difficult at best to get the lay of the land. I resent being questioned about mt ideas of what should be done especially over an internet forum. I am not there Quercus. Your photos don't give me the details that I require should I be onsite. Your methodologies and calculations are yours and you are your own business.... do as you choose. I have no idea if other larger stronger trees are around... I can't be sure you have seen all the things I would see or others may. You cannot in words explain to me all of the parameters involved with this tree so I feel as though I have touched it. Don't dare belittle me with your doings. I suggested an outcome...fair in my judgement based on your few meagre shots of your glove and a path and a tree cavity. If you think you know what to do .....do it. Don't bring me in to an argument because you feel a little hard done by my suggestions earlier about a totally different situation. I haven't seen that one either and may be way off the mark. However the photos gave a clearer view of what was at stake.

24th March 2008, 06:32 AM	#65 (permalink)
TreeSpecialist Semi-mature vigorous tree Join Date: Mar 2008 Location: Austin, Texas Posts: 122	Re: Tree-to-Ground Guying [quote=quercus;25687]doing a good assessment on that tree is pretty difficult because we need to see a lot more of the surroundings. Judging on this picture alone, I'd say that the anchor point is at least 45 degrees off the position where it should be. Like most situations when cabling is needed, there wasn't a good place to cable the tree back to. Located on a 45º slope, and less than 4 feet off the property line to the east, the roots had been removed on the north, west, and south sides of the tree. Target? Any one of 12 condominiums which sell for 1.2 to 2.5 million dollars each. My original recommendation was to remove the tree. Contractor/Owner and City Arborist said save it. With that kind of liability, the structural engineer was brought in. The location of the two ground anchors should have been at least 45º to the east. The best possible location - due east - was on the adjacent property and not available.