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Anchoring semi-mature trees after strong wind


tristan@arbcore.com
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I have a client who has expressed concern after seeing the root plate of his Silver Birch tree moving in high winds. If at all possible he does not want the tree to be taken down or fall down. I have suggested a crown thin/clean and tip reduction to reduce sail effect and weight which he is happy to go with, but he has expressed an interest in using some form of ground anchor to attempt to stabalise the root plate too.

 

This is a new concept to me but I can see some logic in it provided we can find a system which gets the ground anchors well below the moving plate.

 

Additional points: The plate is not visibly moving other than in exceptionally high winds, the tree is approx. 30' tall, there is no threat to persons or property should the tree fail, the client is aware that any anchor system would be somewhat experimental!

 

All opinions and advice is welcome. T.

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i have thought about this quite a lot and tried various things over the years. The Platipus thing is a good idea for installing the ground anchors although I have also used angle iron driven in at 30 degrees to horizontal which has an advantage over Platipus in that you don't need to take so much care over the final direction of the guy wires. Local blacksmith would cut you a few 600mmm pointed lengths.

 

But (and maybe the manufacturer will tell me I'm wrong), guying a 30 ft (?semi-mature) tree at the proportion of total height you would normally do for a rootballed standard is doing the tree no favours in the long run. Guying rootballed trees is to stop the rootball rotating in its hole until roots develop to stop this. The guys should be slackened or removed as soon as the tree can stand it. Your situation sounds different, but the proble is the same, the tree becoming dependent on the guys. What is really needed is some way to prevent excessive movement (the sort that is causing additional root damage or even windthrow) but to allow for some movement that the tree needs to produce the reaction of new rooting and new tension wood whle allowing for repair to damaged roots.

 

The higher up you guy the tree, the more it will become dependent. And rigid guy wires under tension will be the worst thing for it. I would suggest a dynamic rope guy (through a hose pipe or anti-fray sheath - or even pipe insulation I have used) that is to say arope with a bit of bounce in it. Old rock climbing ropes are good for this, and an 11mm will be immensely strong. I have had good results with ground anchors set up, rope round tree at chosen point wiht hose and figure of 8 on the bight (you need to tie this once the rope is round the tree, not that hard), then hook the knot with a ratchet strap attached to the anchor and pretension the tree and tie your rope to the anchor. As you ease off the ratchet strap it partly pretensions the rope, leaving a bit of bounce to accommodate normal winds but to prevent extreme movement in extreme winds.

 

If I had any Cobra bracing with shock absorbers, I'd be tempted to use that instead, it's almost the perfect solution and capable of adjustment for time. I am saving it for a fussy client, perfect way to learn Cobra while on the ground.

 

I'd give the root area a damn good feed too, and mulch it.

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I have a client who has expressed concern after seeing the root plate of his Silver Birch tree moving in high winds. If at all possible he does not want the tree to be taken down or fall down. I have suggested a crown thin/clean and tip reduction to reduce sail effect and weight which he is happy to go with, but he has expressed an interest in using some form of ground anchor to attempt to stabalise the root plate too.

 

This is a new concept to me but I can see some logic in it provided we can find a system which gets the ground anchors well below the moving plate.

 

Additional points: The plate is not visibly moving other than in exceptionally high winds, the tree is approx. 30' tall, there is no threat to persons or property should the tree fail, the client is aware that any anchor system would be somewhat experimental!

 

All opinions and advice is welcome. T.

 

Tristan, I would be interested to know why the root plate was moving in the first place - girdling root system? - waterlogged ground? - surrounding - trees removed? - all mentioned could justify the guying, I wouldn't bother if its root decay

 

Reg Paul

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i have thought about this quite a lot and tried various things over the years. The Platipus thing is a good idea for installing the ground anchors although I have also used angle iron driven in at 30 degrees to horizontal which has an advantage over Platipus in that you don't need to take so much care over the final direction of the guy wires. Local blacksmith would cut you a few 600mmm pointed lengths.

 

But (and maybe the manufacturer will tell me I'm wrong), guying a 30 ft (?semi-mature) tree at the proportion of total height you would normally do for a rootballed standard is doing the tree no favours in the long run. Guying rootballed trees is to stop the rootball rotating in its hole until roots develop to stop this. The guys should be slackened or removed as soon as the tree can stand it. Your situation sounds different, but the proble is the same, the tree becoming dependent on the guys. What is really needed is some way to prevent excessive movement (the sort that is causing additional root damage or even windthrow) but to allow for some movement that the tree needs to produce the reaction of new rooting and new tension wood whle allowing for repair to damaged roots.

 

The higher up you guy the tree, the more it will become dependent. And rigid guy wires under tension will be the worst thing for it. I would suggest a dynamic rope guy (through a hose pipe or anti-fray sheath - or even pipe insulation I have used) that is to say arope with a bit of bounce in it. Old rock climbing ropes are good for this, and an 11mm will be immensely strong. I have had good results with ground anchors set up, rope round tree at chosen point wiht hose and figure of 8 on the bight (you need to tie this once the rope is round the tree, not that hard), then hook the knot with a ratchet strap attached to the anchor and pretension the tree and tie your rope to the anchor. As you ease off the ratchet strap it partly pretensions the rope, leaving a bit of bounce to accommodate normal winds but to prevent extreme movement in extreme winds.

 

If I had any Cobra bracing with shock absorbers, I'd be tempted to use that instead, it's almost the perfect solution and capable of adjustment for time. I am saving it for a fussy client, perfect way to learn Cobra while on the ground.

 

I'd give the root area a damn good feed too, and mulch it.

 

Thaks, that all makes a lot of sense.

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