daltontrees

I have come across this sort of NR money-printing madness. And recently I tried to get to the bottom of it to see on what basis NR can insist on supervising. Indeed, on what basis canit insist on tree removal or pruning. I was unable to find anything but the most ancient and vague of legislation. The bottom line from NR's side seems to be a zero tolerance of risk. The rest of us mere mortals are bound by law only to avoid foreseeable risk that would cause significant harm or injury. NR seems to have a culture of insisting on H&S measures whether it is right to or not. Although I don't envy your situation, if I were in it I would be insisting on a definite statement of NR's legal basis for requiring all these measures. If I didn't get one, then it's a common law issue, involving the usual (mortals) level of duty of care. For the sake of this forum, can you say if it is an eletrified line with overhead wires?

Your splendid fungi directory lists this as saprophytic, but do you know if it is capable of killing wood at the margins? I have been assuming this to be the case but based on fery few occasions where I have had a chance to observe its progression over a couple of years.

It'd be interesting to see how that would go on big jobs. Any moisture at all causes cyanoacrylate to forma skin and harden, so I' wondering if nail varnish remover would act as a suitable thinner and allow deeper penetration before evaporating and letting atmospheric moisture cause the CA to harden. I have a sneaking suspicion that that's how the commercially available wood hardeners work. They are horrendously expensive and a rotted wood sill will drink a whole tin in no time, but it they could be mixed in bulk it would be well useful. Or they might explode, try at your own peril folks and if you survive maybe let us know how it went. I think CA mixed with sawdust can be used as a bulk void filler.

I did half of the Glasgow iTree survey, it put monetary value on hundreds of individual trees. Conversely, I have used Helliwell fo about 20 trees. I will never use CAVAT. I have played with CTLA but have resorted to first principles of DRC in preference to using it fully. So for me iTrees is the commonest.

See my reply to Paul. There is one main flaw, and as such Helliwell valuiations cannot be considered valuations in any conventional sense. CAVAT carries an equally fundamental flaw.

That's what I meant by Helliwell being a comparative system rahter than an absolute one. It originated as you say to quanmtify amenity, then it was later monetised. And that's the flaw with it, the points are multiplied bya published £ per point All trees valued by the Helliwell system are valued by a committee of the AA that comes up with that £ per poiint figure. There is no objective basis for it.

I think by sheer volume the mostly used is CTLA, which is at the core of iTrees.

Did you mean 'flawed'?

Correct, anything multiplied by zero is zero. And so it is with Helliwell system. Use it with great care, I think its usefuleness is as a comparative system rahter than one that delivers absolute values.

There is a standard for assessing ecological/biodiversity/wildlife value. Is it specific to trees? I don't think it is. Does it give any means of weighing up BS5837 categorisation against thiose values? Definitely not. It's back to that thread that Kevin mentioned in which cynicism was rife about the new bat standard. Since then I have worked on af ew bat tree climbng inspections with ecologists. They are roundly unimpressed with the new standard and are largely ignoring it, preferring the BCT guidance. And I have yet to meet an arb consultant who is invoking it for tree categorisation. There is a hole in the guidance that could accommodate any number of bats. I have my own way of dealing with it in reports which in short is to say that 8596 cannot be applied to categorisations.

I think it is too. Although called Broom it is not the same genus as Cytisus scoparius but they are in the same 'Tribe' Genisteae along with Gorse and Laburnum. Most of these are leguminous, the importance being that they can fix atmospheric nitrogen and so can survive in (and improve) organically poor soils.

My thought too.

Only thing is the base of Turkish hazel leaves always extends backwards in 2 more or less round lobes.

Meant to add, most of these fall arrest lanyards that might be incorporated into a SRT are only rated to static loads of 140kg (0.14kN), and would probably therefore be a fraction of the load rating of climbing ropes (typically 30kN) and krabs (30kN). Why ruin the whole system with a weak link?

Or there's this https://www.totalaccessonline.co.uk/Products/Lanyards/Fall-Arrest/2-5m-Retractable-energy-absorbing-lanyard Bumble B just quoted AFAG, quite right. It's probably best not to rely on a device that is needed to cover for bad practice. When retreating from a branch walk, it is virtually always possible to anchor from the branch with a second rope DdRT till the danger of a pendulum is passed. I had a nasty one last week, 14m long Beech limb rising at 45 degrees, nothing on it to hold onto for the first 8 metres, and covered in moss. I went up it a cheval, puxshing in front of me a wirecore lanyard wrapped twice around the stem and clipped to side Ds. There's always a way.

I used to have one for climbing via ferrrata in the Dolomites. VIA FERRATA EDELRID SET - | Decathlon It is really intended for horizontal climbs where if you come off and you are clipped to the fixed wire that is there on a via ferrata the shock is absorbed. It could be incorporated into a base anchor. There's a nother way to do it involving a slip-friction device on the climbing line. If I find a picture I will post it.

Worth considering red alder

I could do with a hand measuring trees as part of a survey I'm doing. I just need the trees tagged, plotted and the DBH, height and spreads recorded on a hand-held. I will be assessing the tree risk ans suitability and management requirements. So, no certificates are required (although familiarity with the measurement principles in BS5837 would help), I just need someone who is technically good, systematic and doesn't make mistakes or cut corners. The main locations are Galashiels, Selkirk, Melrose and Kelso. All equpment will be provided, and a bit of tuition, but you'd have to work mostly on your own, with me nearby for occasional questions. There will be an informal opportunity to ask questions about tree risk and management principles, so it may suit someone wanting to get a taste of commercial survey work. Pay depends on whether you can get to locations yourself or have to be picked up. I don't want quality compromised for speed, but I'll pay extra for a decent number of trees getting done a day. Please send private message if you are interested.

And the TOs were probably told to round up.

Sometimes there is no basal diameter, just stems coming straight out of the ground and spreading all-roads. Willows come to mind. Lime coppice regrowth. A few Lawsons etc.

That's probably me that has appeared to over-complicate. But that misses the point. By trying to simplify RPAs, Annex D makes it more complicated than it is, and introduces unnecessary errors. Personally I think it's pants that 5837 starts off from a presumed circular RPA and then requires justification for deviation from a circle. It should require justification of circles, particularly since in nature these circles never happen. Biut it sits the box-ticking processes of planning for there to be circles, and opens the door to pseudo-arboriculturists. The only beings inconvenienced are the trees.

It sounded fine, and I could see nothing about it to suggest it was an unacceptable risk. There was no apparent opening in the stem. Unfortunately for the advancement of arboricultural understanding, this tree will be left for about 5 years before anyone pays it any more attention than to have their dog 'visit' it.

Nope, I was there. The original post was about arriving at a RPA radius. The area is a pretty useless quantity to know unless you are planning to deviate from the default circular RPA. So the key thing in this posting was the RPAr. Annex D calls this the 'Radius of nominal circle" ('RoNC'). In all cases in Annex D the single stem diameter is exactly 1/12th of the RoNC. But as subsequently mentioned, the RPA is rounded to the nearest m2. This is necessary because the area is always pi x (RPAr)2, which can never be a whole number. I have never used Annex D, nor do I intend to because I don't need to. RPAr = 12 x DBH. And RPA = pi x (RPAr)2. Then I do the rounding at the end, manually or by Excel. The discrepancy caused by rounding relative to calculation is greatest for small values of DBH and RPAr. The greatest is for RPAr 0.90, where the error is 17%. This error disappears to a trivial 0.04% by RPAr 15.00. I don't see that 5837 directs the user to round the DBH up or down to the nearest 25mm. As has been said, this is inconsistent anyway with Clause 4.4.2.6 which says to record the DBH to nearest 10mm. For completeness, the greatest error that could be caused by rounding the DBH to nearest 25mm would be rounding 85mm actual DBH up to recorded 90mm, then rounding this up to 100mm to use Annex D. The true RPA would be 3.26m2, but Annex D gives 5m2. A whopping 53% error (hmm)!. Clearly Annex D will be useful if you don't have a calculator but just as clearly (to my pedantic mind) interpolation is expected or at least possible. And in hindsight it would be better if Annex D used intervals of DBH 10mm. I have put one together quickly if anyone wants it (attached). alt annex D.xls

This is a rather puzzling cherry stem. At first sight I thought it loked like a basal graft and another graft at 2m. But close up it doesn't look like grafts. Anyone got any ideas what's going on?

Slight clarifiction, over 5 stems you use the average diameter, square it, multiply this by teh number of stems and then take the square root of that. The method in the current BS relies on finding the total cross sectional area of all the stems added together, then finding the equivalent single stem diameter for that cross sectional area. The 12.5x 'rule' is then applied to that hypothetical diameter to find the RPA radius.