daltontrees

Ah well you and she will just have to wait and see what my view on that is. Hazard assessments in isolation are about as much use as, say, shoes without feet. And without something to walk on they're both irelevant. Think fuiguratively and you'll see what I mean.

I have my concerns about the use of Monte Carlo simulations only for QTRA, it is the single biggest turn-off for me of the whole QTRA model. I told Mike what I thought about it at the Conference dinner, but after quite a few drinks maybe I didn't put the point as clearly as I thought I did. Come to think of it, he called me (with a grin) a cheeky b..... but took my point. Or so I thought.

Thanks. Unfortunately the NASA threshold is 'harm' and th HSE one is 'death', so they are not quite compatible. But I shall have a look elsewhere to establish the reliability.

Well, I,m afraid that I disagree with this, I think Matheny & Clark were way way ahead of the game on this, for reasons that I will be exploring in my article. The latest ISA manifestation seems to misundertsand them, and the outcome is the proabilistic mayhem that you have flagged up in this thread.

Peer review can take a while, and it's out of my control. It'll come along in due course in one of the Journals.

Yes that clarifies that there is more than one tree. However, isn't the risk of 14 of the trees failing and killing a child each is 1/2 to the power of 14 or 0.000061, following the multiplication theorem of probability?

You've told us what's happening. A fancier explanation might be the behaviour of Homo sapiens manifesting itself. Is there a second question, like should we be doing something about it, and what? Or how did we let it come to this? Or is it inherently a bad thing? Pretty darned good if you're a chinaman living in Dubai called Patel.

Good one! Books refer to these 'heels' as cups. Quite distinctive. Since Picea is pronounced Pie see a, the way to remember this is pull off a needle and if you can say 'I see a' heel or cup, it's 'Pie see a'. Other mnemonics may be available.

Another question if I may? Are there equivalents in the USA and Australia of the ToR framework? And if not, do you consider it universal enough to be applicable there?

Another thought, would analysis of the ISA system in numerical terms not benefit from a Monte Carlo simulation to better define the overlaps?

Sorry, I don't follow this. Have 14 children been killed by one tree? Doesn't the risk arise from a hazard and the harm is done when a tree fails and then once failed that hazard cannot fail again?

Sorry for delay in replying, I have been inordinately busy lately. Your original post makes it pretty clear what you would like to do. But it's still not clear why you want to do it. I mean, you are representing the commercial interests of QTRA Ltd., are you not? It wouldn't be the first time Arbtalk has been used for commercial interests, in a way that's partly what it's for, for people in the tree business to help one another. But in so doing the benefits are shared within the business. This research is generally a deserving area of work, and as far as I am concerned you are entitled to ask for people to chip in. I suspect you already have the answer. I sould also explain that I have been working on this issue for about 6 months, covering it as part of a bigger piece of work that at the time you posted last week I was tidying up for submission for peer review and publication. Since then I have been doing 2 big tree surveys and using these as an opportunity to thrash out some concepts in my head regarding quantification of tree risk. One piece of information had been missing, namely a copy of Matheny & Clark's 1994 book, which I got through the post last week. I am glad I waited for it, because the hazard rating it introduced remains the foundation of most if not all proprietary quantitative and qualitative tree risk assessment methods and I was missing some of the perspectives on this that required the whole book and not just the abstracts that I have been using for my draft.

Your pictures are a wee bt vague, I am trying to imagine what you have seen... In the meantime here's a thought. There is a superficial similarity between rocks and trees in cross section. The rock formed from sediments. If you get a handful of dirt and shake it in a bottle then stand it still to stettle, in a few hours you will see that the largest particles (pebbles, coarse sand) settle out first, then fine sands and silts, finally clays. Some stuff will hardly settle out at all. This is what happens in nature, a blast of sediment comes into a lake or shallow sea from a storm in the mountains, and a layer of sediment going from coarse to fine forms. Next time another layer is laid on top of it. The layers can represent one year, as the bulk of sediments coming into the lake or shallow sea can be in spring with melt-water. The tree forms from vascular vessels and woody cells. In spring the tree comes out from dormancy, flushes its leaves and draws huge amounts of water up the stem for transpiration and photosynthesis. The ring-porous trees in particular develop very big xylem vessels for water transportation in the first couple of months of the growing year. Then the tree settles down for the rest of the year and puts on smaller vascular vessels. This accounts for the ring structure of wood. Trees and rocks therfore both have the same characteristics, each layer or year's growth starts with large vessels or partiles and grades into smaller particles or sells then stops for the year or season. Manys a time on the beach I have been stunned by the similarity between sedimenraty structures and wood structures. I will dig a bit deeper and see if I have a few photos in my collection to illustrate. Before I was a full-time tree-bore I was a part-time rock bore.

It's still the middle of May. The Ash up here aren't even in leaf yet. C.f highly unlikely.

I don't think it is a Spruce. It could be a young vigorous Abies alba. The growth all seems fresh and new and maybe disguising the more familiar identification chracteristics. Like cones, mature needles with white bands underneath and mature bark.

Torture but possible if you have tiny hands and an endoscope. I used my 12V charger on a soft tyre last week. I went in for a cuppa, came out 10 minutes later and the tyre was sort of pumped up. But the current it drew from the battery and the bit of resistance in the fag lighter socket from dirt caused the plug to melt, it folded when i PULLED IT OUT, LIKE A BIT OF THIN CHOCOLATE ON A SUNNY DAY. iT IS NOW UNUSEABLE. Transit tyres are very hard work for these wee pumps. They are just about OK for car tyres to 25psi, but Transit 3.5T to 60 psi, basically they'll never get there.

If you know for sure that it's Dinantian, that makes an explanation even easier. Whereas sedimentary layers are generally laid down horizontally and then lithified (squeezed, baked and turned to rock), not all rocks preserve a perfect stratified form. In the Carboniferous period, the centre of Scotland was essentially a large rift valley, a descending mass of crust between two even bigger masses of crust that were separating slowly. The land to the north, currently the highlands, was a source of sediments. The land to the south, currently the southern uplands, was also a source of sediments. However, the main character of the central lowlands was that it was at sea level. For a while it would be just below sea level and would have been rich with life, particularly coral reefs and silty lakes or seas where sealife debris like shells and reefs that were very calcium rich resulted in limestones. As these areas bult up to sea level, they became choked with silt and sand, giving us mudstones, sandstones and siltstones. Some of these yield fossils of bivalves. In time, the area would become stably terrestrial and would have been characterised by swamps with primitive plants and trees. These are the source of scotland's coals. But back to that rift valley. With an intermittent, juddering descent of the central block downward, the areas of 'land' were periodically submerged and became shallow seas. After a dump of new sediment, the area again teemed with marine life, and the commencement of the next layer of future limestone was underway. This happened in the scottish lowlands cyclically many many times. A look at the stratigraphic record shows a more or less perfect conformable cycle of limestones, sandstones, coal measures, thin sediments, limestones, sandstones, coal measures etc. So in this context you need to think of recently disturbed sediments, still in a quasi-liquid state, being subjected regularly to earthquakes that were probably on a San Andreas Fault scale. The central lowlands is riddled with smaller faults too, what is known as syndepositional faulting that happened during rather than after sedimentation. Local topography would result in underwater and terrestrial landslides. But you can often find an even simpler phenomenon in scottish carboniferous rocks called 'dewatering structures'. This is where the otherwise clean planar structure of the sediments has been bent, billowed, slumped, folded or sheared, while the sediments were still soft. On the Fife coast in carboniferous rocks I have seen almost spherical plumes of rocks which have been cut through by weathering to give concentric circles. Maybe you are seeing something similar, i.e. lamina distorted before lithification.

Looks metamorphioc to me. Where exactly did you find it?

I thought that too but it has alternate leaves and the mystery one has opposite leaves.

Try Osmanthus decorus.

It looks mighty familiar, it might come to me over breakfast.

I'd second that, although I know it by its synonym Ganoderma adspersum.

I think their suitability for situations is a bit misunderstood. In nature when they are growing close together they shoot up in competition for light and couldn't stand up on tehir pwn at that height without companion shelter. When more open grown they take their time a bit more and the height to diameter ratio can be much lower. Lower branches live longer and spread further and the tree stays more squat. Still a big'un but tolerable in urban environments.

There's no right answer. I was working last week with a brand new Juno and an oldis Geo on the same survey. The Juno was preciser but inaccurate, the Geo wqas imprecise but accurate. When you're in amongst trees and buildings it is just not possible for a device to interpret compromised satellite signals and produce an accurate and precise position. It's like trying to find out where someone is shouting from in a canyon.

Serious question... why?