The aim of demonstrations?

Paolo,

I find your attitude in this post very hard to understand.

As someone involved in training I'm acutely aware that during demos and events things that can go wrong have a tendency to go wrong.. Murphy's law in action I suppose. It's a reason for being extra meticulous when preparing and setting up. But sometimes things still don't go exactly to plan. Actually, thinking back, my first post on TB was about something that went wrong during a rigging demo.

In my opinion a professional attitude in this respect is to try to minimise slip-ups in my own events, to understand what goes wrong and avoid repeating the same mistakes and try to improve delivery and content continuously. Professional behaviour is not blowing the whistle on others and pointing fingers.

In all honesty, who out there can maintain that nothing has ever gone wrong. Paolo, everything always gone exactly according to your plan?

There is a red thread in many of your posts, that everyone else is misguided and/ or ignorant that I find tiring in the extreme. With this post you have crossed a line, what you are saying is malicious and borders on slander. It also makes you appear a tad... loopy.

Same as Nod I'm not interested in getting into long-winded debates over this, in future just try to tone it down a bit. Thank you.
 
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Quite simply Mark, you weren't there and you aren't a registered instructor or assessr with the organisation - you cannot truly understand the balanced picture. Your insights are influenced by those you work with. Your blind support is admirable, but in this instance of no relevance or credibility.

This thread was aimed at repeated poor practice from those organisations that are responsible for promoting good practice, rather than individuals, although obviuosly they are implicated, which is unfortunate. However, we are often judged by the company we keep, and it is down to each individual how they choose to manage that.

This is about what is constantly happening in the UK industry frame work of training, which is very onerous carrying serious legal implications for instructors and assessors and their clients.

Yes of course things go wrong and I appreciate that, but when certain organisations repeatedly get it wrong, doesn't it say something about the organisers focus and credibility?

And for the record, I've never made repeated mistakes during my teaching career - in fact I can't recall I've ever made a mistake when training, though i expect i will have somewhere down the line.

Nothing I have stated is slanderous - because its the truth. As for 'blowing the whistle' not being professional, the alternative is unchecked performance leading to ineffective training in a very dangerous occupation - and I'm sick of it - all other avenues of complaint have been found ineffective. I know of the innocent fatalities and serious injuries that are related to ineffective training. Who cares that you find my posts extremely tiring and why should they? Perhaps you should look to yourself as to why that is?

Its quite simple: if charged with a responsibility to present industry best practice, then that is what should be presented. When it repeatedly isn't then that is incompetence. It would be nice to rely on an independent authority to sort it out, but there isn't so poor presentations continue and standards are trivialised, not raised.

I am well aware that my view is unpopular with some, but that doesn't make it untrue or invalid.

Some of the major issues in this industry are hampered by a select few that feel they are elite, and that they alone are best placed to progress/manipulate industry.

I don't.
 
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I have been discussing that demo with a friend of mine that attended, he was saying something about research having been done on the forces on rigging points in the tree, eg, removing limbs increases the forces on the rigging points but leaving them on helps dissipate the forces through out the tree canopy.

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Removing or retaining branches doesn't change the weight of the suspended branch or the forces on the rigging system, it just has a dampening effect on the rest of the tree which makes it more comfortable for the climber.

If you overload an anchor point it'll break regardless of what limbs you decide to leave, the failure criteria remains the same. If I'm worried about the strength of an anchor point, I'll reduce its weight which reduces its overall load. Yes it becomes a little more jerky and ridged but so what, surely it only adds to the load bearing values. And yes highscale, I agree with you. When in doubt, cut the branches smaller and keep the guidelines clear and simple.
 
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Removing or retaining branches doesn't change the weight of the suspended branch or the forces on the rigging system, it just has a dampening effect on the rest of the tree which makes it more comfortable for the climber.


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Contract,

Yours is a popularly held misconception...the tree IS part of the rigging system.

Every part of that tree is intrical to the dissipation of forces when rigging.

The oscillating effect of a straight spar(no branches) when dynamically loaded is increased...so increasing the forces on the timber of the tree...which is part of the rigging system.

Leaving branches on can decrease the risk of stem or branch failure by decreasing the oscillation/jarring/wobbling on the rigging system which includes the tree itself.

The dynamic force of the rigged branch is increased when there is increased stem oscillation.

Thanks
 
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Quite simply Mark, you weren't there and you aren't a registered instructor or assessr with the organisation - you cannot truly understand the balanced picture. Your insights are influenced by those you work with. Your blind support is admirable, but in this instance of no relevance or credibility.

This thread was aimed at repeated poor practice from those organisations that are responsible for promoting good practice, rather than individuals, although obviuosly they are implicated, which is unfortunate. However, we are often judged by the company we keep, and it is down to each individual how they choose to manage that.

This is about what is constantly happening in the UK industry frame work of training, which is very onerous carrying serious legal implications for instructors and assessors and their clients.

Yes of course things go wrong and I appreciate that, but when certain organisations repeatedly get it wrong, doesn't it say something about the organisers focus and credibility?

And for the record, I've never made repeated mistakes during my teaching career - in fact I can't recall I've ever made a mistake when training, though i expect i will have somewhere down the line.

Nothing I have stated is slanderous - because its the truth. As for 'blowing the whistle' not being professional, the alternative is unchecked performance leading to ineffective training in a very dangerous occupation - and I'm sick of it - all other avenues of complaint have been found ineffective. I know of the innocent fatalities and serious injuries that are related to ineffective training. Who cares that you find my posts extremely tiring and why should they? Perhaps you should look to yourself as to why that is?

Its quite simple: if charged with a responsibility to present industry best practice, then that is what should be presented. When it repeatedly isn't then that is incompetence. It would be nice to rely on an independent authority to sort it out, but there isn't so poor presentations continue and standards are trivialised, not raised.

I am well aware that my view is unpopular with some, but that doesn't make it untrue or invalid.

Some of the major issues in this industry are hampered by a select few that feel they are elite, and that they alone are best placed to progress/manipulate industry.

I don't.

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Great Post!!

Sometimes the truth is hard to deal with!
 
Tockmal

Thanks for clarifing/explaining the theory, I'm sorry I don't agree.

Wood will bend so far before it fractures and breaks. Whether the wood oscilates at a faster or slower rate makes no difference to this. If you take a twig and bend it back and forth at a really fast rate, its not going to make it any weaker than if you did so at a slower rate.

In a rigging situation its concievable to assume that if you're using a perfectly vertical stem as a lowering point, the retaining foliage/air could create enough resistance to reduce the initial 'bending' factor of that stem when it comes under load. However, a more horizontal anchor has more lever-arm when under load and further top weight can only be detrimental. Why else do we undertake weight reduction to keep trees upright.

I think its the word oscilate that's both inapropriate and irelevant really. But hey, its a catchy term at the moment in the treeworld so lets all keep it in circulation.

Generalisations are dangerous, especially when it comes to training and subjective interpretation.

My point was really more of a word of caution to any aspiring riggers out there who might have been influenced by the oscilation theory. Dont be the dead hero who tried to bite of more than he could chew while waiting the oscliation factor to kick in.

I like the manner of your posts Tockmal and I'm glad you made this very relevant one. You see members, its possible to disagree without choking on our ego's and falling out!
 
The way I like to imagine the 'ocsilation' descriptor is a tuning fork example. If you were to have little arms laterally extending off the tuning fork it would not 'resound' for the same duration, as the laterals would absorb a share of the energy.

Contract, I think your descriptor could be narrowed/clarified as it does contradict cycles to failure theorem. Maybe a better metaphor/analogy might be flicking the stick with your finger? Bending it as you described (to my imaginary vision of what you described) would likely be the same force used just at different speed rates........come to think of it this is the issue to start with. (in a sense) The single tuning fork will resonate with greater speed. We sense that speed (see energy) as sound. If less sound is made; less energy is made audible, therfore absorbed. (or less existed to begin with)


If I keep going I'll start sounding like Spydie!
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Mangoes

To me, you've just desribed the dissapation and longevity of energy absorbtion, I don't see what that has to do with rigging forces. Unless you're telling be that I can take one less wrap on the lowering rope then nothing has changed.

If I try to winch a tank into a tree, the anchor limb will break when it reaches its failure criteria. Leaving other branches on elsewhere wont change this. However leaving weight above the anchor can only add to the load.
 
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To me, you've just desribed the dissapation and longevity of energy absorbtion, I don't see what that has to do with rigging forces. Unless you're telling be that I can take one less wrap on the lowering rope then nothing has changed.

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Yes you are right this was my direction of thought.....I misunderstood the conversation, thought it was trying to understand energy dissapation.

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If I try to winch a tank into a tree, the anchor limb will break when it reaches its failure criteria. Leaving other branches on elsewhere wont change this. However leaving weight above the anchor can only add to the load.

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As alluded above this clarifies the inititial conversation (I think) regarding maximum static strength.


Both directions of perspective are valid though. Rope is a great example. Dynamic ropes are tested to maximum failure (see final capable strength of wood) and the ropes ability to absorb and dissapate energies. (see tuning fork metaphor) Both are valid perspectives, but I see you angle that absorption makes no difference if you cross critical failure load.
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The aim of demonstrations?/harmonic oscillations

A lot more is going on here than just energy dissapation.

On rare occasions if the resonant frequency of the tree trunk and the resonant frequency of the rope and load happen to be close to each other we may see driven harmonic oscillations while rigging loads.

Driven harmonic oscillators:

http://en.wikipedia.org/wiki/Harmonic_oscillator

As an experiment tie a rope part of the way up of a small dead spar in the woods making sure the rope is long enough to get you out of the danger zone. Give a pull on the rope and watch the spar. Time successive pulls on the rope to match the flexing of the spar(the spars resonant frequency) and very large forces will be created. This is a driven harmonic oscillator circuit.

Wind can also excite the resonant frequency of trees in the same way.

Old Tacoma Narrows bridge failure:
http://en.wikipedia.org/wiki/Resonance#Old_Tacoma_Narrows_bridge_failure

I feel positive that a certain percentage of tree failures (both natural and man caused) are a result of resonant frequencies being excited.
 
Re: The aim of demonstrations?/harmonic oscillations

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I feel positive that a certain percentage of tree failures (both natural and man caused) are a result of resonant frequencies being excited.

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Very appropriate wording Dan, well said.

The reduced oscillation strategy is something to consider for whatever advantage it might bring to a particular situation, but is only one of many consideration's and trade-off's which must be calculated when devising a rigging strategy. Whether you decide to implement it depends on whether or not it compromises another value, and which one should take priority based on how critical they are to the particular situation

This thread was about training but when highscale brought in the oscillation factor I jumped on it for a reason.

In the last 12 months I’ve spoke to several people who have suggested the same thing on the grounds of what they've been told by training companies. Forget, take the tree down in the most logical and systematically simple sequence, no its consider and first prioritize the oscillation energy flow disapation factor. An Irresponsible subjectively interpretive dangerous generalization, that is somehow the foundation to make everything else alright?

Whilst I have the greatest of respect for both Nod and Paolo, I wasn't at the demo in question as I'm not an instructor, so I can't comment on what happened there.

However, Instructors, please try keep the message clear and logically prioritized to work within the realm's of what is realisticly achievable. Treework needn't be complicated or confusing. However, its clear from what I’ve experienced that a percentage of the trainees are coming away from these workshops with some pretty mixed up theories.
 
The aim of demonstrations?

To sell equipment . If you are watching a demo to find things wrong with what they are doing , you'll probally find something wrong with what they are doing . If your goal is to be the perfect instructor for instructors that sounds cool , but is that a practical goal or an ego trip . How about a instructor competetion ?
 
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If you are watching a demo to find things wrong with what they are doing , you'll probally find something wrong with what they are doing . If your goal is to be the perfect instructor for instructors that sounds cool , but is that a practical goal or an ego trip .

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Thanks Riggs, that was refreshingly sane. I agree.
 
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If you are watching a demo to find things wrong with what they are doing , you'll probally find something wrong with what they are doing .

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Sounded to me like Lazarus2 was watching a demo and it was impossible to ignore all the things the demo team were doing wrong...in his opinion. Some of which sounded like they were basic mistakes...in my opinion.

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If your goal is to be the perfect instructor, is that a practical goal or an ego trip?

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From what I understand of Lazarus2's first post it sounding like he was making some observations of a demo he attented.
I didn't see him make any references to being a 'perfect instructor'. So your point is irrelevant.

I'm glad people express opinions about industry meetings/seminars/demos. If you want everyone to be dumb then why didn't you just say that?
 
Re: The aim of demonstrations?/harmonic oscillations

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The reduced oscillation strategy is something to consider for whatever advantage it might bring to a particular situation, but is only one of many consideration's and trade-off's which must be calculated when devising a rigging strategy.

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Contract,

The critical point of a rigging removal is when you begin to drop loads from above into rigging blocks eg topping out.

Throughout the tree's life it has been subject to constant dynamic loading by the weather. The tree has responded and adapted to outside influences in order to maintain it's optimum growing strategy(Claus Mattheck's - The Axiom of Uniform Strength).

So with this in mind...surely it is better to use the tree's naturally existing energy absorbtion/dissipation capacity to your advantage when climbing and distmantling the crown?

I recently removed a 90ft Sitka Spruce and decided to leave a line of branches intermintently up the stem during the removal process. When it came to taking the top out the difference in stem movement was incredible! even though I had a good groundsman who let the top run, the branches acted as a major buffeting force against excessive movement.

The biggest difference was when it came to dropping vertical sections into the block, again, the stem hardly moved . I felt a lot safer on the spar.

But your right...it is a tool which can only be understood through experience of different rigging removals. New trainees who have been taught the theory are in great danger of applying anti-stem movement/positive dissipation theories incorrectly.

If in doubt, rig small pieces from large diameter rigging points.
 
Re: The aim of demonstrations?/harmonic oscillations

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The critical point of a rigging removal is when you begin to drop loads from above into rigging blocks eg topping out.

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Tockmal, that should be 'a critical point of rigging removal can be', which is the point I was making about generalizations i.e. We took down a mature but dying Oak today which all had to be lowered down. I have no pictures but I can assure you that the top sections were the least of my concerns!

I shouldn't really need to add further examples or analogies about where I'm coming from with this. Please read the posts again and if they still seem a little inconsistent, PM me with your telephone no. or vice-versa so we can elaborate in a fraction of the time that it will take me to type it all out for this thread. Thanks

Mark, Tom, can I just use my real name from here onwards instead of contractclimber. I mean, Ive never even had a contract in my whole life, well apart from the serious one with my wife.

Anyhow I dont like it anymore, sounds pretentious and well...just dumb!

Thanks
 
Re: The aim of demonstrations?/harmonic oscillations

Sorry that I derailed the thread.

Good imformation though.
 
Re: The aim of demonstrations?/harmonic oscillations

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Tockmal, that should be 'a critical point of rigging removal can be'

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Point taken.

I guess there is only so much talking on this subject we can do before we debate ourselves into a quandry.

I know what you were trying to say.

Thanks
 
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