daltontrees

I just found this, you got to get the variety too. Not connected to the Battersea picture, by the way.

Damn, haven't looked in on this thread for a while, I would have got both the last two. Easy to say that in retrospect though. Here's one for you, I don't know the answer(s). It's in Battersea Park, I took the pic without investigating further as I was in a rush and being ushered by wife mumbling about "tree-bore" again.

I have read both those articles before, very good. Sorry if I sounded patronising, I cna never remember who is who on Arbtalk and how knowledgeable they are, so I just went for an explanation that any reader might follow. You're right, that is less than 70% wood, but I think we both share the sentiment, it is not volume (or cross sectional area) of wood, it is also quality of wood that matters and the soft-rotters take the biomechanics to a new challenging level.

I believe kretzschmaria is the settled name. Adopted by the British Mycological Society with their chosen common name of Brittle Cinder. Ustulina is certainly easier to spell. The other one I need to remind myself has no less than 6 constonants in a row, tzschm looking like the Scrabble hand from hell. I'll bet tehre aren't any other scientific names of fungi or anything that have 6 constonants in a row, unless Mr Kretzschmar or whoever he was was a prolific eponymous namer of things.

Reply to Treeseer's comment. I am no expert on K. deusta, like most people I rely on the decades of knowledge and research by others, so what I say comes partly from my own experience but mainly form authorities such as Schwarze, Lonsdale, Engels, Mattheck etc. I don't know the extent of your understanding of the terminology, so I will assume little. Some fungi decay lignin, some cellulose, some both and some lignin then cellulose. It is the loss of cellulose that results in brittle fracture. What K. deusta does in the right conditions is weaken the cellulose (by hollowing out the cell walls) without much perceivable loss of wood volume or density and I believe some of the strength characteristics of affected wood can remain largely unaltered too. Except of course the crucial matter of tensile strength. Failure is sudden when the loss of tensile strength is overcome by wind loads. This is what I mean, if the extent of wood is being assessed by a hand groping around in a cavity, I don't think that it's quality can be gauged at all, and its quantity only roughly. Attached are a couple of pics from a K. deusta F. sylvatica victim from last year. A bit of an extreme example but the external bark was largely intact and there is well over 70% wood. Adjacent residents told me it snapped and was down in seconds. The ruler in the poicture is 20cm long. The tree was about 20m high.

There's one extra picture of the base of the tree on Flikr that ahows just how close this monster tree is to the house. I am following the speculation about the pros and cons of mulching but ultimately no-one on the forum has seen the size. density and shape of the canopy or the extent of decay and whether it is assymetric. In a worst case scenario the canopy could be heavily leaning towards the house in a northeasterly direction and the decay could be K. deusta related and ready for brittle fracture regardless of extent of wood left. Personally I would advise getting a professional inspection and opinion and reasoned strategy for risk management. It may be something that an insurer could look for retrospectively if the warning signs were obvious.

I reckon you're right with spheroblasts, but they could be wasp galls. Birch seem very prone to Taphrina deformans too and do the strangest things.

Av, is it possible when you have time to outline how the QTRA system factors in or is adapted to deal with a fairly typical situation where the target is exposed to the possibility of a whole tree failing at the base and thus a whole canopy of branches coming down, say 20 metres wide, ranging from 1mm to 600mm diameter? There is arguably a whole spectrum of IPs. And a second question, again if and when you have time, does QTRA differentiate between the IP of a branch of given diameter falling from the bottom of the canopy at 3 metres and from the top at say 20 metres? Thanks in anticipation of your clarification.

As saui before, without actual usage figures or local knowledge the values can't be ascertained but the relative T values you have allocated seem appropriate to me. I would be focusing on the variations arising from individual trees at road junctions, proximity to residential buildings and pedestrian nodes nd any overhead utilities.

It looks like a well used woodland, the Stretview pic of the bend at Vicars walk shows good paths and signage. I don't suppose the actual figures matter in this exercise though. So far it feels like the risk zoning that I already use. I see there is more than an order of magnitude of probability between Target Ranges in the QTRA system, but I am parking my concerns until the lesson is over. We can chat about it at playtime.

Thanks Rhob. It is all very curious. And I suppose one should consider too the possibility that in a full moon there could be night-time leaf transpirational or respirational modes that contribute to the concentration of compounds in the leaf. Or maybe the full moon coincides with night-time insect feeding and the trees have evolved to counteract this by sensing the full moon and producing higher concentrations of insecticides. This is starting to hurt my head. In brief, the moon causes a twice daily high and low tide, high being when the gravitational pull of the moon is at its strongest and when you might expect fluids to be helped up a stem the most. On top of that the sun causes a twice monthly spring and neap tide, spring (not the season but the tide) being when the sun's gravitational influence is highest; these coincide with the full moon and the new moon. So, high spring tide is the biggest on two counts. I have just realised I don't have any point to make.

OK donme the first bit, albeit without actual; traffic counts and knoiwledge of pedestrian usage, but I get the idea so far.

People have probably stopped looking in on this post but I am going to ask a quaestion here about lunar pruning. 'Sap' is sometimes used to mean water (mineral enriched or not) rising to the canopy. It is also used to refer to the sugar rich fluid heading generally downwards from the canopy to the roots. Pruning on the lower stem about this time of year on Acer or Betula usually causes profuse sap bleeding. Now, this could be either the collapse downwards of either kind of sap or the release of upwars moving sap under pressure from below. Or both. So if lunar cycles result in changes in gravitational forces within the mobile fluids in a tree but also changes in the groundwater pressure on tree roots from without the tree, which kind of sap bleeding would high tide or spring tide encourage? Does the question even make sense? I think I mean are there 2 good times a day to prune or 1 good time a month?

Av, thanks for the worked example with the picture of the manual calculator and the software screen shot. It has illustrated the QTRA system as much as (and in conjunction with) everything else you have said.

Hey JonnyVine, don't worry about offending me, I had just come in from the pub and thought I was being funny in my innuendoland reply. I really ought to use those emoticons so you knoew I was saying "thrust" in a Benny Hill tone of voice.

And then sold it to Tescos as barbeque charcoal...

Oh dear, I see we are in innuendoland! I had thought the general thrust of my argument would have over-ridden everyone's individual urge to fixate on the nuts and bolts.

To Acer ventura Comments noted, I wasn't having a bad day just a busy couple of ones in a row. As you are the sort opf person who clearly tries to use languiage precisely, a term such as 'nuts and bolts' was always going to be wooly. I suppose what I meant and which you have more or less confirmed is that the PN really just says that there are nuts and bolts but doesn't let us see them. I suspect the people opn the Forum will reserve their position on QTRA until tehy have the nuts and bolts in their hands to poke and pull at and satisfy themselves that they are solid. You are now getting asked a lot of questions and I am not for now going to trouble you with any more. I would just reiterate that the example in Kelvinside is effectively confidential but that I am quite happy to describe exactly the Black Pine situation (without stating what I then advised and why) and if you are willing to illustrate what advice your approach would have resulted in I will simultaneously do the same. The spoecific case doesn't matter, it is more for onlookers and me to understand how your system works in practice and what a more rudimentary system does by comparison. I do not want conflict, only advancement of understanding. It can go in a new thread if need be, this one is bifurcating like an Elm branch.

That was easy.

I'd go with K. deusta too. Whatever it is it is really quirte a beautiful pattern, I'd cut a thin slice and polish it and put glass on top and have it as a coffee table. Unless it's really smelly (he says, fishing for further clues)!?

Quick response to Jose's post. If Council refuses an application and the damage then caused by a tree was foreseeable, the Council is statutorily responsible for compensation. Have a look at the Act, I can't remember the English Act paragraph.

Attached is a pic of the Black Pine being topped out.

Hi all, exhausted but free after several hard days' survey and tree work I have alittle time to catch up on the debate. Please take my earlier comments in context, I am often leaving the house at 7am, 2 hours before light, measuring and chalking up tree diameters in the dark so that I can start survey at 8.30 or 9 if it is overcast. And back home at 5.30. Or as happened this week we were taking down a large Black Pine that shifted considerably in the wind and rain last week. I was 15 metres up it in the dark trying to redistribute its centre of gravity. I characterised it as urgent and advised the owner to get rid of it despite the expense. You can use it as an example if you want and can question my judgement on that advice. Let me know and I will provide details. I have a a lot of first-hand information about the tree. My snippiness last posting came from tiredness, lack of time and what I perceived as criticism of my professional judgement. I would prefer to see QTRA justified on its own merits than by trying to find inadequacy in my methods. Acer Ventura is clearly very eloquent and a practiced in rhetoric, and I would not like to see the opportunity for open discussion stifled by fear of attrition. Moving on, I have now just read the Practice Note. It doesn't really show the nuts and bolts of QTRA but what it does tell me is that the methods I use are similar. I do not try to put across the financial savings on tree work and the tree benefits of retention that might come from refinements of our version of risk assessment. The client invariably makes the view on that clear. We advise then we take instruction then we act entirely within that instruction. So back to the Practice Note ("PN") and what I understood from it, and I think this might illuminate things a little for anone still looking in. The PN says much about probablility of target being present at the time when failure is most likely, which I think is QTRA's strongest suit. It says a little about the severity of harm and attaches weighting to it relative to the cost of damage to property. It says relatively little about the assessing the probability of failure. Let's say the three things that combine to produce the overall risk rating are these; target presence, severity of harm/extent of damage to property and likelihood of failure. Where I think people struggle to complete the arithmetic is the last one. It is really difficult to evaluate. A weak fork, an extensive cavity, an already lifted root plate, no matter how good our invasive and non-invasive investigation toolbox it is very very difficult (I would go as far as saying impossible) to pin down, even to differentiate between say a 1:5 an a 1:50 probability. Yet, such parameters may be enough to take the overall risk from 1:1,000,000 to 1:100,000 or from 1:100,000 to 1:10,000. The PN as I see it says little about this, but are there any users that can say whether QTRA is helpful on the matter or whether this is left to the judgement of the inspector and the limitations of budget for sophisticated investigations. Or both?

Sorry, I scarcely have time to eat and sleep these days, the Forum is a luxury. However, byu now I feel as if I am defending myself for jocular commetns directed at RobArb whom I know would like help to get his head around the quantification of risk. I don't have a problem with it and my methods are more sophisticated than you seem to think. I'd rather not be the cadaver that is dissected for this particular subject, and we may just have to disagree about whether a tree-owners duty of care can be discharged without the use of QTRA. I and my clients are/am satsfied with the results of my black box and I shan't have to explain in court why someone didn't get hurt. I am sure the courts will find QTRA reassuring but the law doesn't say you have to use it, just what you need to achieve.

Just a brief note. I can't share this specific calculation with you because it would be a breach of client confidentiality in terms of my contract. However, I would be willing when time allows to reproduce calculations for a hypothetical tree in the same situation. Rob, if you stand under such a tree for 5 years you will come a cropper. If a rota is drawn up whereby you have a 1 minute slot in those 5 years where you have to stand under the tree, the risk to you is still unacceptable because you may get the minute when it alls over.