Tree-to-Ground Guying

treeseer

Colleagues,

The old oak in the pictures has a wound ~50% of the circumference and ~6' high halfway up the trunk, on the side opposite the house. I can shove my entire handsaw in the gap between the woundwood and the xylem in several places along the edges of this wound. I can also shove it straight into some of the cracks, to a depth half the length of the blade.

Crown reduction is not a reasonable option given the age of the tree and the severity of the defect. The best management option seems to be a guy cable installed from a point above the defect and anchored into the ground. I reviewed the ANSI standards and the BMP's with the client, and our course seems clear. I have specified ground anchors only twice in the past, and cannot confirm whether these were installed, or recall seeing others.

Can you please refer me to successful cases of tree-to-ground guying? The client would like to know of some before going ahead. Sorry for the crappy pic of the wound; light was bad and i forgot to adjust the camera. 6 dead limbs around this wound and i have no clue what caused it. Theories?

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playfordtree

I am not an Arborist Treeseer only a humble tree lopper so i cant offer advice of that nature, but i am intersted to know if the tree is in such a bad condition and so close to the house why you wouldn't suggest euthanising the tree and starting again with a new tree?
Please educate me.
regards Simon.

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Euthanizing South Australian Trees
since 2007

Eric Frei

I only see tree to ground guying on transplants where they want stability to help the roots make new ground and prevent blowing over.

What I dont understand is that you want to guy above the defect to a point below. If the defect or branches over the house fail they fall anyway or get hung up.

If the tree moves the guy wires will perhaps pull of heave on the defective area exacerbating the weakness.

How is a ground anchor going to help?

Regarding heavy pruning ... if you dont will nature do it for you?

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bigshea13

nasty wound. ive used long bolts on severa
occassions for similar problems. you can get 5-6 foot lags and use large washer or scab boards on each end. put it threw several feet above crotch. even though its not in the correct spot it will if nothing less keep the leader from crashing on the house when nature severs it. another off the wall method is to purchase a long strand of cable and a large length of garden hose and another long lag with an eye. this is a last resort method but it works. wrap the cable around the upper {damaged portion} over a healthy crotch and down the back side of the tree{as if you were rigging it for removal} until you can find a stury spot for the lag and eye. place the garden hose over the cable{just to reduce friction on tree. connect the cable to eye. the set up will move with the entire tree and create less friction. the one main downfall to this is the visibilty factor but sometimes you can hide it well. if the leader is going to fail and you justg want to buy a little more time and still kepp the dwelling safe this will do it. when it does fail you just go up cut it out of the cable and go from there. kinda like a fishing night line for trees

arborjockey

Do you have a picture of that?

bigshea13

if your talkin to me the answer is no. but if i get some time i can draw you up a diagram take a picture of it and post it if youd like

quercus

I'd like to see your technique, Bigshea...

By not seeing the surrounding area of this tree, I'd suggest large concrete blocks placed at a distance from the tree that is larger then 1.5 times the crown spread. Estimating the size of the tree, I think they'll have to be somewhere between 25 to 30 metric tonnes of weight. Are there any other trees that may come in handy as an anchor point?
Placement of cables is also discussable. What will the main purpose be? holding the crown on the tree untill it eventually collapses of will you let nature have it's way and deflect it away from the house in case of a structural failure? For this last tech, you'll have to determine winds and speeds that go back as far as decades.
Reducing that windload could be accomplished by deadwooding, and crown opening on the inside. Wish I could explain it better.

Could you take some more pics of the wound and of the tree and it's surroundings?

What is your budget on this? very very important on this one.

Treelore

That wound seems pretty high in the tree. I am thinking ground anchoring is overkill. why not triangulate a cobra cable system to branches that are strong below the wound. Most of them seem to be growing up past the wound height. The picture doesn't tell everything but it seems you could cable from just above the wound in a spoke like pattern radially to other stronger stems????

treeseer

That much, eh?No.Yes, plus the thought is that a cable would lessen movement and thus lessen the likelihood of failure. The crown is very open already, due to the loss of the 6 branches. I deadwooded it yesterday. Yes that pic of the wound was crappy; I will try again with morning light.Not infinite, but the tree is of high value.

Ekka I hear what you are saying about the guys pulling "off heave" and that is a concern. I'm not sure what the tautness should be, or whether using two guys would alleviate or exacerbate that concern. O and ps I linked the client to this thread.

bigshea13

best i can give ya. i dont have any cool diagram software so i drew it and photoed it.? the hose just reduces friction and the lag offers a small amount of structural support{cobras would be better} and the cable is attached to a fixed point on the tree itself. no need for cables to be strung across or threw the air or to large pieces of concrete somewhere in the yard. like i said..set it up like you were rigging with a cable.

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treeseer

/well thanks for that effort, but...
1. I don't want to drill through the trunk below the defect.
2. The hose at the top crotch might not be enough to prevent damage, given the load on it.
3. I don't understand the physics involved. Something seems a bit off, and it is not in standards or bmp's.

hey quercus, we are talking about blocks of concrete IN, not ON the ground, right? Hence "tree-to-ground".

quercus

It seems like the only plausible idea. Concrete block pouring is not that difficult and I have done it before succesfully. The only thing that can be seen above the ground is the eye of the lag bolt, wich can be cut of when it is not longer needed. If accessible by crane the block can also be removed in one piece when the tree is gone. Also a block of 15 metric tonnes is not that big when it comes to concrete. I have poured blocks of 30 tonnes each.

What you do is you measure the volume and dig the hole. Then you punch in steel rebar of 1 meter long and 1 cm thick on various heights and on each side in the sides of the hole. Punch them in the sides with a hammer about 50 cm deep. So the other 50 cm can be locked in the concrete. Have a large lag bolt cut to length and put a stick in the eye and lay it on both sides on the ground on a brick. So the lag bolt is now suspended on the stick and will come about 20 cm above the ground. Be sure to dig at least 30 cm deeper then the volume you calculated. The blocks have to be at least square like a cube. Or even better is that they are deeper then what they measure on the surface.
Both blocks may not be more then 45 degrees sideways to the axis line of the tree target. Now pour concrete into it with a large mixer. When it hardens put the ground back on the top of the block. You now have a serious anchoring point. The more distance the more shallow is the angle of the cables to the tree. This is way stronger then a steep angle, and lets you dig in an area where there are no major roots. Anchor the cables as high as possible in the tree. I'd suggest at least 10 tonne MBS pre tensioned dynamic cobra bracing for this.... But still, we need a lot more pics.

Another possibility is that you have a steel cable with 2 loops spliced in the lag bolts and put the lag bolt completely vertical in the concrete block so that only the eye sticks out. The steel cable loop then comes above the ground as an anchor point. This is even stronger then what I mentioned before.

When completed this tech shouldn't cost more then 4000 usd.

Eric Frei

Yep, I did write about it here to.

Also 1m3 of concrete weighs approx 2500kg

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quercus

Yes I forgot to mention that. Concrete weighs between 2200 kg and 2500 kg's per m? depending on the mixture wich depends on the use.

treeseer

quercus, your thinking is in line with what i had in mind but i do not see the cost near that high, and i do not see how cobra would handle that weight. given the lack of trunk flexibility and the weight of the top i expected to use 7 ton ehs steel cable.

TREE-SURFER

Has Oak Wilt been considered? As the infected tree dies back the infected area, shutting down, say the limb, will cause it then to break off.
Since oak wilt causes drought-like symptoms, it may be easily confused with other stress-related factors. These factors include construction damage, drought stress, or insect colonization. In addition, oak wilt is often confused with the common springtime disease, anthracnose. In contrast to oak wilt, anthracnose causes spotting, curling and browning of the leaves in the lower canopy. In rare cases oak wilt may cause brown streaking of the inner sapwood. This streaking is a good diagnostic symptom for detecting infected trees. If any form of anthracnose is diagnosed, it will be better if the infected tree is removed and burned in order to reduce any further risk of infection to other trees.

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The Aerial Arborist

Isle of Man Tree Surgeon| All Aspects of Tree Work

What experts say about TOPPING

quercus

I'm talkin' about total cost mate... It adds up fast, you know...

You have...

-excavator to dig the hole (excavator must be delivered and operated too)
-cost of getting rid of the extra soil and transportation of it
-steel rebar and concrete, lag bolts and spliced steel cable
-delivery of the concrete and pouring, with or without the use of a concrete pump to cover the distance
-cobra cable, hose, dampers and spreaders or steel cable with splices, straps for the tree, and maybe some other things
-your fee, for measuring, regulating, overlooking, installing and tensioning the whole damn thing
-renting a dynamometer to tension the thing... or where you planning on pulling on it without measuring the tension?
-then new lawn must be layed over the concrete blocks

Add this all up plus some extra for things you didn't expect to encounter and you'll come close to what I said.

And remember this about the cobra cable... It'll give it the finesse to the job it deserves. Plus it's far more attractive and pretty sight too. Single ten tonne cobra cable will mean you have a pulling force of over 20 tonnes. You have to remember that you need to keep it in place... you don't have to lift it. The tree as a whole must still be able to move a bit. That's why you need to measure the tension you put on it.You need to allow it to move, but not far enough to break.Depending on conditions, wich we still haven't seen in detail, I'm guessing 1 to 3 tonne pre-tensioning of the cables. Too low will mean your whole construction is worthless, too high will mean that vessels and bark and cambium on the opposite side of the wound will get stretched and ripped apart in time, and thereby weakening the tree even more.I've seen this before and the outcome was that cables got untensioned in time and the tree had to felled. The tree, if healthy, will form some overgrowth and could become stable again. Static anchoring of a tree is specified for very rare and occasional conditions, like for instance a co-dominant stem breakaway, combined with bolt stitching. But in that case, the tree is cabled to the tree, and not to something else.

Eric Frei

Any new pics yet Guy?

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Treelore

Fraid I can't go with you on this one Q. 1-3 tonnes of tension is crazy. 30 tons of concrete is absurd!! Unless I am seriously missing something( better pics would help) the total weight of all components above the constraint would be very lucky to make 2 tons. This simply needs to be braced. All that is required here is a bracing and fall arrest system.30 tons is about 15 cubic metres of concrete. That could stop a train!! If to ground is your only option The US offers great wire ground fasteners that are rated to about 20 tons a piece and all that is required is a sledge hammer and a steel shaft. They work on the same principle as a snow pig.

treeseer

Nah dammit I had to go in another direction today. Mebbe tomorrow.

quercus

Weight may not be that much. Momentum when the tree has leaves could far exceed the weight though...

jim1nz

I think Quercus weight figures are not too far off the mark. But just remember when you burry a certain amount of weight, the deeper you burry it the harder its going to be to pull out... 10 ton of concrete 1m down is going to take a hell of a force before it comes out of the ground, even 5 tons of concrete.

You will have to reinforce the concrete also.

The more guys you have installed the better too right? 6 Smaller guys is going to be better than 3 or 4 bigger ones...Wouldnt you have thought?

TreeDimensional

I have watched this post from the beginning. I thought there were more pictures coming. Most everyone is on about saving the tree. There are two things that haven't been discussed. The first think is, what other issues have been addressed, has the trunk been increment bored to see if there is heart rot present? The second thing is, how is lightening protection going to be incorporated into the grounding system?

I don't think any of the discussion has any merit without seeing the whole picture, literally.

jim1nz

Good point Brent

treeseer

Yup, better show some more of that tree. What happened to the wanker who started this thread?

pic 1 is the base; 1 root wiht a little rot, 1 with a big burl. Overall, well anchored. former driveway around it will have gravel removed and mulch applied.

pic 2 is the defect--exactly 50% of the circumference, spiraling, and 10' long. heartrot is not a concern so no i am not drilling it. Cracks are a major concern--i can stick my handsaw blade all the way in at one point.

probed around, nothing punky in there. i can also stick my handsaw between the woundwood and the xlem on both edges of the wound. xylem is very hard and very tough, no idea what caused the wound.

pic 3 is me standing where the proposed ground anchor would go. my TIP is just under where I would install the cable. I will go look at the tree on a windy day, to see how--or if-- the trunk moves.

Again, extreme reduction instead of support is a last resort. I may reduce a few tips depending on confidence in any support system. There is way too much solid and valuable tree there for the owners to talk about removal.

how do you put pics in the body ekka? i got a bunch more.

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bigshea13

looks like good firewood

quercus

Thanks for the pics. Can you draw an X on the picture of the whole tree where exactly the wound is. Now I've seen this, I'm sticking to my calculations but I'd use more cobra cables. One attachment point on the block with a V shaped double splice or ring splice approx. five to six meters from the tree to get more anchoring points. I'd brace it as high as possible with less pre-tension, say about 250 to 500 kg's.
When using these big concrete blocks, they can be used to do some more cabling for the rest of the tree when the situation gets worse in time. So no need to pour any more blocks further on. Gotta look ahead.You say you stand on the mark where the block must be poured, but remember you'll need TWO blocks. Depending on where the mark of the wound is, I'm guessing you're cabling too low.

Sean Freeman

Guy, I have been following this threradhere and at TB, someone over there posted a pic of a helilcal screw, and without wanting to derail at all was wondering if anyone has any experience of using screw piles in stabilising trees in any way not just in the specific example here. In oz there are companies using screw piles for exactly such an application.

Screwpile Australia - Applications Tension Anchors

I'll add my thoughts to the questions in your original post, but need to know whether you were expecting/or feeling that failure was most likely in the stem or in some of the larger limbs? If it were the limbs that had your focus then Cobra or rather TreeSave would be my choice a dynamic support sysytem or fall arrest for the major limbs then massive efforts to improve and invigorate the soil and roots.

Maybe some diagrams might help clarify things a bit let me try with the pic you put up.

treeseer

Here is a pic of the base of the oak and ones that will show I hope the wound relative to the rest of the tree. The wound runs from 7-10m up this 13m stem.


The 2nd pic you can see the top of the wound where the Trunk narrows.



The 3rd pic shows a side angle; my TIP is 1m above the top of the wound.


Pic 4 is the top of the wound, with the only sign of active fungi.


Branches are sound and well attached; it is only the stem defect that is bad. Anyone who looks at this tree and sees firewood must also look at the Mona Lisa and see tinder.

quercus I think the necessary stretch can be accomplished with a dampening spring in a steel cable. I am disinclined to cobra due to photodegradation and squirrel predation concerns, as well as appearances and client (and my) confidence.

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quercus

please draw a mark on the pics exactly where the structural defect is...