Stringing cable between trees

[Stuart91]

I've got a job coming up later in the summer which involves running some speaker cable through a park. There are certain pathways where it makes sense to sling the cable up through the trees in order to keep it clear of the pedestrians. So far, simple enough - it's something that I've done plenty times in the past.

 

The complication this time is that apparently previous contractors have used a combination of rubber matting and rope to ensure that the cables don't touch the bark directly. This was explained to me by a countryside ranger who couldn't explain any of the techniques but seemed adamant that it had to be done this way.

 

I know next to nothing about trees, but I'm finding it hard to believe that pulling through maybe 20m of slack cable over a branch is going to damage the bark in any way. (We're talking mature trees 50+yrs old, and the bark at ground level feels like elephant hide). Assuming that it is a problem, has anybody got any tips for getting around the issue?

 

I'm keen to avoid unnecessary work at height - the ground is uneven and there will probably be public blundering around during the installation.

[paulears]

Have you seen the effort tree surgeons put into climbing trees without damaging them? They take it very seriously. from my brief conversations, the issue with rope - I wasn't asking about cables is the fact the trees move in the wind, so do the ropes, and it can do damage to the bark - and in bad cases do real damage. You'll have to do it their way, I guess.

[ddproduction]

If you want the cable to stay still, you'll actually need to put up a tension steel wire and attach your cable to that - this would put a lot of stress on the tree bark!

[Stuart91]

the issue with rope - I wasn't asking about cables is the fact the trees move in the wind, so do the ropes, and it can do damage to the bark - and in bad cases do real damage.

 

I can appreciate that, to a certain extend - especially when the rope is supporting the weight of a human. But we're talking a single cable, with only its own weight, and it's going to be in place for less than 36hrs.

 

 

The cable doesn't need to be totally still, so I don't think a cantenary wire is necessary. We have enough clearance that a little droop on the cable won't be a problem.

[ImagineerTom]

If there's any possibility of "the public" being under the cables you sling then you're going to need some sort of cantenary or secondary support system up there if you're going to get through even the most basic of RA's - animals climb on cables, birds land on cables, vehicles drive under them, stupid people throw things at them, wind blows them making them move/vibrate and shake free. You will need "something" holding them up there to withstand these fairly obvious complications and whatever that support device is will be putting potential strain on to the tree which will need protection.

[kerry davies]

Have you shown the Ranger what sort of cable you wish to run? Why drag speaker cable, why not chuck a coil over? Is there a real problem with wrapping a few branches in waste cloth? (We used to use miles of army blankets when we built scaff stages to protect the canvas from the tube.)

 

I suspect that the Ranger is thinking of heavier cable which had rope as a catenary. It seems overkill to use rope which will probably be heavier and more damaging than speaker cable. But I also suspect that you are going to end up doing some WaH just to comply with the Ranger's wishes.

[Stuart91]

The cable in question is bog standard rubberised flex, 2x1.5mm so not exactly heavyweight. My usual practice elsewhere has been to lob a coil over but there's always some dragging to get the slack pulled through.

 

Wrapping some branches wouldn't be a major problem, but it's a bit of a time consuming pest which we could do without on a day that's too busy as it is. (Plus, at the out, we'll have all the climbing to do again to remove the wraps, rather than just being able to pull the cable off)

[david.elsbury]

I think that in this age of arborists and tree protection, it's just something you have to accept and do- and move on! :)

[themadhippy]

My usual practice elsewhere has been to lob a coil over

Know anyone with a bow n arrow,makes cabeling through trees much easier,and fun

[Stuart91]

I think that in this age of arborists and tree protection, it's just something you have to accept and do- and move on! :)

 

I will as soon as I can find someone to foot the bill for the additional labour... ;)

[Junior8]

How times change as Kerry says in the past we'd have just slung it up pulled it tight and on to the next one. Ten minutes work if that mostly. Chance of damage to tree about nil I would say.

[peza2010]

I think that in this age of arborists and tree protection, it's just something you have to accept and do- and move on! :)

 

I will as soon as I can find someone to foot the bill for the additional labour... ;)

 

Its fairly irelevant if you can find someone to foot the bill or not - if the man in charge of said trees wants you to wrap them in something, then wrap them in something.

 

I can think of plenty of things that ive had to do to keep people happy that are worse than this.

[Stuart91]

How times change as Kerry says in the past we'd have just slung it up pulled it tight and on to the next one. Ten minutes work if that mostly. Chance of damage to tree about nil I would say.

 

That pretty much sums up my thinking - it seems like a complete over reaction. I suppose, like many things, someone has at some point damaged a tree and this has led to knee-jerk reaction.

 

I'm still curious if there are any recognised tricks or techniques for "protecting" the branches without taking up too much time or effort. Kerry's suggestion of wrapping the branches makes sense, but I'd still like to minimise the work at height if possible.

 

Its fairly irelevant if you can find someone to foot the bill or not - if the man in charge of said trees wants you to wrap them in something, then wrap them in something.

 

I can think of plenty of things that ive had to do to keep people happy that are worse than this.

 

I did put a wink at the end of that sentence for a reason. ;)

 

But it's still irritating to find what should have been a simple job "growing horns" like this, especially since it doesn't seem to be based on any solid evidence. I'm all for going the extra mile for customers when required, but it's far nicer to find out about requirements like this before the price has been agreed with the customer. I'm now probably going to have to cover an extra crew member out of what little margin was on the job to start with. </rant>

[david.elsbury]

You could always avoid the working at height by putting the cable on the ground in yellow jacket cable ramps. ;)

 

Or could you dig it in? One spade slit and job done.

[ImagineerTom]

But it's still irritating to find what should have been a simple job "growing horns" like this, especially since it doesn't seem to be based on any solid evidence.

Bark is like skin for a tree, it keeps problems inside and hidden; it stops outside problems getting in. As soon as you damage bark (or cause internal damage by squashing dying bits of internal timber that without your intervention would have remained reasonably structural for another 10 years) you put a tree on an almost inevitable spiral of problems that will cost someone else a lot of time and money further down the line. These problems happened in the past but the outdoor events industry & frequency of events has grown exponentially which means that much more damage is happening and people are actually around long enough to note it; add on to this the wide range of skill-sets and experience in event crew (some of my regular crew are tree surgeons but to an outsider they look and sound no different to the minimum wage agency crew hired in at the last moment) and you can see the need to be over-cautious and introduce some blanket rules to prevent bigger problems occuring.