Arborist’s sonar

I came up with this one a good ten years old, if not more. For some reason I had to think of it today, still makes me smile…

All the funnier in fact, since Paul Howard told me the story during the Augsburg set-up of the time when he was setting up the crew on site, left one of the guys in front of the property to fell a spruce, went round the back to sort out the rest of the work, when he heard the noise of a chainsaw firing up, following by the whooshing sound of a tree falling โ€“ followed by a weird sound, a bit like… plastic deforming. Upon closer inspection, it transpired the tree had been felled straight through a Port-a-Loo, cleanly (well, not really!) splitting it in two, with the content explosively voided up the side of the building.

Yuuurk! ๐Ÿคฎ

Now that is a pure arborist’s sonar-moment, if I ever heard of one!

Wheeeezes and validation fails

Did I mention there was a lot of pollen coming off those lime trees?

I kid you not, I have never seen anything like it, absolutely extraordinary. The ultimate irony being that the bees actually seem not to be very keen on silver lime blossom, when it would seem that there is rich picking there. Oh well… ๐Ÿ๐Ÿ๐Ÿ๐Ÿ

Oh, and then there was this… went to buy some lunch from the supermarket round the corner from the park, then had a picknick in the park. One thing I bought was a rice milk drink with added Macha green tea. What can I say? When I opened it I felt that Migros really need to rethink the styling of the product if they want this to go mainstream and not remain a niche product selling mainly to folks who have a fetish with drinking scummy snot.

Just goes to show how essential it is to validate and field test thoroughly before you go to market, regardless of whether you are considering a PPE product โ€“ or a rice milk drink. Just that if you get it wrong, in one case you are left with a slightly gross drinking experience, whilst in the other the consequences are potentially much more serious.

In the same vein I thought this was an interesting case: the other day I was looking at someone’s e-bike, seemed like a well kitted out unit. Unusually though the battery was integrated into the seat post, which other manufacturers usually do not do, the more usual format tends to be to somehow to integrate the battery into the frame around the down tube. The owner of the bike then told me that due to the width of the battery and the fact that it stands proud of the saddle, every time you pedal, your thighs chafe against the corner of the battery. Now that is what I would consider a foreseeable failure โ€“ and really something that again validation ought to have caught.


So there you go, welcome to the kind of things that preoccupy me whilst asphyxiating in a blizzard of lime tree pollen…

Spot the obvious

Nice day climbing today, pruning an alignment of silver lime, Tilia tomentosa.ย The structure of the tree makes for some interesting work-positioning challenges, you really get the impression the wood fibres are being maxed out, with long lever arms and lots of weight at the end in form of foliage. This results in some creative lanyard use, v-rigs โ€“ and some interesting rope angles.

Oh, and of course today was the new me: new access line, new climbing line, new RIG, new helmet, new harness. I felt like a total rookie! But just as well, the old gear was getting a bit tired. And I won’t even mention the helmet! I swear it made a growling noise at me out of my gear bag the other day! ‘Nuff said!

The dust from the blossoms and leaves had everybody hacking away like troopers. Let me put it this way: if I were a bee, today would have been a score! There was pollen absolutely everywhere! Still, on the upside, the fragrance was quite something.

Felt a bit bad after cutting of this chappie (see below): even after having been cut in half, he was still smiling.

But back to the job… the lads from the council were on ground work duty.

As the park is in the middle of town, this is actually really important, as on a sunny day the park is absolutely heaving with people. Fairly early on it became apparent that the guys assigned to us were not the most… dynamic. Their work process involved lots of sit-downs and smokes. Umm, yes. So I could not resist documenting this situation, try and spot the blindingly obvious. No prizes for this one, keep your postcards for harder quizzes.


Jascha about to ascend into the tree, the last lot of trees not cleared, the boys on a more or less well-earned rest. But they are safe: their rest zone is all taped and barricaded off. Which could not be said for our work zone. I let Jascha handle this one, by this time I was ready to blow my stack.

In the end they moved the barricade after a bit of coaxing. Memo to self: never take anything for granted, even โ€“ or especially โ€“ the apparently blindingly obvious.

Memos to self

Slightly stuck on the rescue dummy theme, I realise. Do not worry, I will move on to others, but I could not resist sharing one more…

I was on the road a couple days this week, running a aerial rescue session in eastern Switzerland. Don came along for the ride, he behaved and all went smoothly โ€“ maybe more about that in some future post.

I manhandled Don out of the van this morning, in a stroke of genius I strapped a skate board to the bottom of the spine board, which is great โ€“ so long as no one tells the kids!

Memo to self #1:ย Do not attempt to haul Don down the steep driveway to the cellar by yourself wearing the klumpen (wooden clogs) you were given after last year’s ETCC in Netherlands, or else DEATH BY KLUMPEN IT SHALL BE!

Memo to self #2: Do not unload Don just as your lovely, but also rather frail 94-year old neighbour is going out to do her shopping. You will most certainly give her a nasty old fright โ€“ QED.

Resilience, again

A couple of days ago, Nat and Stuart Witt dropped by for a visit, over from BC in Canada. We had a nice day together with loads of coffee and lots of chatting. One of the things we did was that we traipsed up the tower of the Mรผnster, the cathedral in Basel. Considering it was built in the twelfth century in a earthquake zone, it has weathered the passage of time pretty well. OK, granted, during the great earthquake of 1356 the third tower fell in the river Rhine โ€“ but apart from that, I mean…

We were up the tower at noon when the bells start ringing. Stuart pointed out that the whole tower was moving, which I rubbished. To then realise… that the tower was moving! Quite noticeably so in fact. The movement of the bells cause the whole stone structure to move from left to right. For this reason, amongst others, the building was constructed with grouting which was softer than the red sandstone used for the construction of the cathedral โ€“ in the wind the towers sway up to a meter from side to side. Quite impressive considering they are 65m high, that is some oscillation!

I cannot even imagine how a medieval engineer or architect would have calculated all this, but it would seem they got their maths right.

Similar to aircraft wings or the towers described above, the movement of trees in the wind serves to dissipate energy. Rather than the movement being being unnerving, on the contrary, were the structure to be immobile and rigid there would be cause for concern. All the examples above are strategies in resilience, allowing the structure to deform under load and thereby withstand it, to thereafter return to a state of relaxation, the original form.

Like the aircraft engineer or the medieval architect, when the arborist considers an anchor point for rigging or climbing, for instance, he or she will be estimating the range within which the structure will be able to withstand load before irreversible or catastrophic change occurs.

After all, we want those towers to sway nicely, not fall in the river, metaphorically speaking!ย ๐Ÿ˜‰

Ken has left the building

In my experience, rescue dummies very much live a life of their own.

Take Ken, for example, my stalwart Simulaids rescue dummy of the past years.

Every time I was getting ready to go someplace, everybody around the house seemed happy to lend a hand… until lugging Ken out of the cellar into the car came into play. He had a knack of inappropriate behaviour. One time one of his hands managed to come lose just as we were manhandling him past a box full of old crockery which was due to be taken to the flea market. Well, after Ken’s passage that crockery was reduced to lots of little bits. I suppose you could have always sold it as a puzzle! With a tube of super glue…

This was also one of the things I liked about Ken: he weighed in at a realistic weight. It drives me nuts when aerial rescue demos or training sessions are run with a dummy weighing 50kg (100lbs). I mean, really?! The risk being that solutions and techniques are identified which under real circumstances, with a average weight climber plus their gear, will simply seize up or prove to be otherwise non-viable. On the downside it did make him quite a lump.

So yes, Ken and I have been through a lot together. Any number of TCCs, workshops and events…

There was also that dramatic moment during ETCC in Turin where we ran a AR scenario where the casualty was stuck on a pole on spikes, meaning poor Ken spent his weekend on spikes on a pole. Which later on turned out to be a mistake, but more of that in a moment… anyway, in Turin, just before lunch break, Ken dropped a leg, making a touch of dramatic field surgery necessary.

Thinking of rescue dummies at comps always reminds me of one of my favourite stories in this department which happened during a comp a while back, when the climber blazed up the tree, slapped in an anchor point, bombed down to the dummy, established a load-bearing connection โ€“ to then snap his anchor point! The anchor point came screaming past him and the dummy, narrowly missing them… but fear ye not! The dummy rescued the intemperate climber.

Dummy 1, climber 0ย ๐Ÿ˜Šย And so the tables can turn!

Then there was that time when Ken joined us for the ETCC party in Monza. Come morning he had vanished. We found him again quite a fair way away in front of Mat Glenn’s tent in some weird yoga position. The less questions asked the better.

Things really started going bad when recently Ken started shedding limbs as a matter of course. In the Czech Republic workshop a couple of weeks ago he got legless. I hate to think what would have happened had someone been standing underneath as it came down…

It turned out that over the years Ken’s joints have really gone to hell. I replaced three knee joints, now both hip joints were shot, as well as the joint between pelvis and torso (don’t bother checking, you don’t have one there, this is dummy-specific). So I decided that enough was enough. Time for Ken to move on.

Roll over Ken, welcome… Don!

Unlike Ken, who is a Randy 9000, Don is a bog-standard Rescue Randy. The difference being that the Rescue Randies have a steel frame under the plastic. In theory the ball joints on the 9000s reduce the risk of pinching fingers in joints, but in practice… well, see above.

Ahh yes, the charmed life of rescue dummies!

Insights and self-doubt

Last week I was able to run a workshop outside Vienna with Arbor Technical Institute Kreitl in Raasdorf, where I have not been for years. Good to be back there, really impressive outfit, loads of potential, very coordinated and extremely well set up.

I was working with a group of maybe ten people, quite a few of whom are trainers for Marcel Kreitl. This is a size of group I enjoy working with, the overall level of competence was high, allowing for interesting, lively discussion. The overall topics were planning for emergencies and aerial rescue, as well as a rambling discussion about resilience and creating it where lacking. Often as not, sessions like this will offer up a small gem of insight where you least expect it. This one was no exception.

When discussing resilience, I like to point out that part of what you are doing is weighing up safety margins and the ability of a system to buffer adverse conditions versus efficiency. In this sense, you can opt for maximised safety factors and large buffers โ€“ at the cost of efficiency. On the other hand, you could also go all out for maximum yield and efficiency, throwing caution, safety factors and buffers to the wind. The third option is that you weigh these various factors up against each other, maybe incorporating extra mechanisms or features, by doing so creating resilient systems, able to withstand load or adverse conditions, to thereafter return to a state of relaxation.

(Sorry, I realise I am being long-winded, I am heading towards the point I am trying to make, bear with me)

Whilst running aerial rescue scenarios, one of the techniques being employed was the counter balance for access line rescue. One of the climbers, a highly competent and experienced person, ran into an issue whilst performing such a pick-off rescue… he was running a friction hitch made entirely of high-modulus fibres. This hitch works fantastically for him in ever-day use, but when it came to attaching the splice side to the line to the casualty to be able to perform the counter balance, he was really struggling to get it to cinch down on the line reliable, in order to prevent himself from sliding down the line.

I thought this was interesting, as it unexpectedly showed how the resilience discussion even pertains to how you configure your friction hitch โ€“ which was not a connection I had made so far. Based upon the considerations above, you can opt for an ultra-reliable hitch, with a very high safety margin, but at the same time very low efficiency and lots of friction โ€“ making it highly impractical. Or you go for the bare minimum of wraps and braids, meaning you have to coax it into cinching on the line โ€“ with little safety margin, but in a sense higher efficiency (Mind you, a quick caveat here: it is debatable as to what is being used to assess efficiency here, so the analogy is not 100% correct. Arguably, a friction hitch which hardly bites cannot really be described as being efficient, as it is unable to perform as it should. The point I was trying to make is more the weighing up of safety, buffers and one measure of efficiency).

So it transpired in this instance that whilst the balance was well struck for a normal load distribution in every-day climbing, that the blend of materials of that friction hitch cordage did not possess sufficient margins to be able to create sufficient friction to hold a full body weight whilst installing the figure of eight prior to descent. This is not a general statement regarding high-modulus cordage, but proved to be so in this case, with this cordage combination, with this climber’s mass and this hitch configuration. In my books this is exactly why we need to practice aerial rescue โ€“ and therefor offers a valuable insight.

The climber in question was visibly disappointed with himself, feeling somehow that he had failed his rescue โ€“ mind you, after a bit of cheering up, the next day he ran it a couple more times, on different friction hitch cordage, problem solved. I cannot state it often enough that in my view, competent operators are not people who do not make mistakes, but rather are able to apply the appropriate tools and techniques to solve problems if and when they encounter them. ย This climber ticked all those boxes, he persevered and resolved the situation.

It will always remain a mystery to me why it is that less competent people tend to over-estimate their abilities โ€“ whilst competent people chronically under-estimate themselves. Well, actually, there is of course loads of research into this phenomenon (in part described by the Dunning Kruger model), but still, when you see it playing out like this, you cannot help but be puzzled.

This is one of the reasons I enjoy these workshops: they feel worthwhile, allow me to work with teams and individuals, identify issues and develop problem-solving tools โ€“ as well as link up dots between topics where I had not seen connections before…

Image courtesy ofย Arbor Technical Institute Kreitl

En route

En route to Melnik, Czech Republic, to run a workshop.

I have been lucky and privileged to having been able to witness the evolution of the Czech arborist scene over the past fifteen year. Returning every couple of year has been like watching the process through in time lapse photography: From the early days when there was just a handful of idealists and pioneers, through to today, with a well established industry with youngsters coming to events for whom it is a given that an arborist industry exists.

What other industry offers the possibility to experience this kind of process first-hand?

On the way here I decided to skip a visit to the Mayday Motel… ๐Ÿ˜‚ย The mind boggles.