daltontrees

Long section of Cistanthera papyvifera showing what I suspect are sieve plates. One of my favourite slides for this reason.

This thread is for any interesting pictures, discussion, techniques etc. for discovering more about trees by examining them under the microscope. I will kick off with a few random pictures of my own. First is the cross section of a conifer needle. If I find the slide again I will confirm the species. Please look in from time to time even if you are not participating. If nothing else the pictures can be very pretty.

Too late, I couldn't help myself I have started a thread in Tre ehealth care since it's not just for pictures and it's related to tree physiology. See you there.

Tony, you or I should start a thread on trees uinder the microscope. I would have done it a while ago but I thought I was the only saddo on Arbtalk who would look at it.

To refine the point made by others, in UK law if the harm or damaged caused by the tree's failure was reasonably foreseeable then the owner is negligent and liable. As ever the difficulty is foreseeing. Foreseeing a car being there might not be that hard. Foreseeeing that a tree falling on it would damage it isn't that hard either. Foreseeing the tree falling is the tricky bit. If the rot wouldn't have been apparent to a reasonably skilful inspector, liability would be hard to prove. If the rot was apparent, it still might not have been enough to cause concern. But if the rot was extensive and the tree's failure was inevitable (I think the ISA system uses the word 'imminent') the owner is liable. Somewhere in the middle is a degree of decay that takes the risk from acceptable to tolerable and then another degree that takes it to unacceptable. If the decay resulted in unacceptable risk the owner is liable. If it resulted in tolerable risk the owner would have to show why he tolerated it despite the risk. That's the UK situation anyway. No-one yet has mentioned t/r ratios. That might be a good way of trying to quantify the residual strength. After all, if one is approaching the assessment (even retrospectively) as a VTA, the third stage is estimating the strength of the remaining parts. t/r ratio is part of the toolbox.

I woudl justy add the possibility of viral infection, basically dysfunction due to mutation of cells and then rapid proliferation, very like cancer.

I am intrigied, sir. What are these scopes to which you refer? Do you mean microscopes? If so, I would be happy to swop notes with you as I am a dabbler myself but have hit the buffers on thin-sectioning due to lack of knowledge on how to soften woody structures without damaging their detail.

Ash plus height from ground equals likely I. hispidus and startts to rule out any Ganoderma.

The subject has been beaten to death, but I just want to add an obvious (to me) point. The figure of 8 is very very easy to tie on the bight (5 seconds), whereafter it can be clipped into a krab (another 5 seconds), but in rock climbing iw Ould always tie the figure of 8 as a single then pass the tail, through the harness bridge (not through the krab) then complete it as a follow-back to double it up. It makes for a super-safe knot as strong as the harness. Can explain with photos if anyone needs it, but it has little if any application in tree work.

One of the enduring attractions of the figure of 8 is that if it doesn't look right it isn't right. The same is harder to say of the Bowline and harder still of the Yosemite. And I was talking about rock climbing. If you are stuck in a freezing gully with spindrift everywhere and cold hands in thick mitts, the Yosemite is an unthinkable option but the figure of 8 can be tied and checked by the numbest hands and mind. Surely the same applies perhaps less extremely in tree work? And it IS stronger than the Bowline. The only attraction I can see in the Bowline over the figure of 8 is it's ease of undoing after loading. The Yosemite doesn't make it any easier or harder in my experience. I have never seen any tests on its strength relative to teh Bowline, but I expect it is stronger. Sorry, I am not clear on what you disagree with. That I will never use a Yosemite tie-off again?

It has the habit, bark, haws and leaves of Crataegus crus-galli (Cockspur Thorn). The species has vicious thorns that make ordinary Hawthorn look poofy by comparison. Does your trees have thorns that would rip your eyeball out like a sausage on a cocktail stick?

I am coming to appreciate very quickly that there may be few situations where the rules of thumb in the guidance can be relied upon without any further adjustment. As the document says "A simple technique cannot cover every situation...". I am trying to develop my technique with sky protractors so that as well as using the guidance I can check the results against the British Standard. Who knowsd how the scottish Act is going to produce guidance to deal with deciduous trees and shrubs in hedges? The 5%/25% rule is just about manageable for evergreens but it all goes to pot when deciduous hedges come into play.

3m of 8" wood is approximately 0.1m3. Multiply by the density of green wood, typically about 1 tonne per m3, so should be about 100kg. 3.5m would be 117kg. 3m of 10" wood is about 0.15 m3 so it's about 150kg. 3.5m of 10" would be 175kg. Manual handling regs suggest no more than 25kg lift per man, about the weight of a standard bag of sand. As wood gets seasoned it loses up to 40% of its weight in water. You can estimate from that how dry your wood is and what a length is likely to weigh. It depends on species too. Lighter wood like dunkeld larch is around 0.85 tonne/m3, denser wood like oak is up to 1.06 tonnes/m3.

Ach well, it has been looked at about 4600 times, so I suppose it passes for some sort of diversion for people.

I watched that video, will never use a Yosemite tie-off again... A quick look on Google showed up that this is the knot that nearly killed famous american climber Lynn Hill. For rock climbing I always use the figure of 8, it's stronger but seizes if it takes a fall. But if I peel off the first thing I care about is the knot not coming undone, then the rope not breaking, and way way down the list is how easy it will be to untie the knot.

I thought there would eb at least one. Anybody else from the bish-bosh end want to add their names to the subbie blacklist of the i'd-never-do-that end?

Then everybody stop posting! Unless someone wants to say they would have been proud of it?

That there is my biggest fear... Have had a few kittens on white willows, moving a metre side to side in 50 mph gusts, hands so cold I had to tie off and curl up in a ball with bare hands in oxters inside the waterproofs for 2 minutes till I could feel them again.

Gor! This has gone on a bit. I was mostly annoyed that they had inconvenienced road users, but I've got over it now. I don't care who they are and a witch-hunt is pointless. But their main offence was posting on You Tube. You can take whatever part of the spectrum of I'd-never-do-that to bish-bosh-home-for-tea you want, but would anyone on here have been proud enough of the obviously amateurish performance to want to put film of it in the public domain? Darwin says what happens eventually to the gene pool after individuals ignore screeched warnings and walk under falling trees, but he's not quite so explicit about the consequences, for the individual and the species, for people posting videos of it.

I haven't looked in for a while. I like your thoroughness and logic. In short, it is unlawful to obstruct, letting a tree obstruct is therefore unlawful; this creates a statutory requirement to unobstruct and therefore falls within the ambit of the Planning legislation to prune without TPO consent. I always thought the 2.4 and 5.2m 'rules' were metric equivalents of 8 and 17 feet. Is there something in the highway code that limits vehicles to 16 feet? I am not sure of your logic on the 'without lawful authority or excuse' part of the Act. It is saying it's not an offence to obstruct if you have some authority to do so. A need for TPO consent could be seen as temporarily preventing authority to remove an obstruction and at a push could be a defence against prosecution until consent comes through or the need for it is waived. So while I agree that the only way the law could approach TPOs and obstructions would be exemption, I don't think the 'without lawful authority or excuse' part has any relevance, if anything it might operate in the opposite direction. Trees are seen as different even if they are not mentioned in the Act. They are the only thing in nature that can create a structure in somebody else's airspace by stealth. They are encroachment and arguably trespass, but it is not an offence to let a tree encroach. The owner of the airspace is allowed to cut them back but the tree owner is not obliged to do so unless nuisance has been established. This grey area continues (in my mind) over roads, where the highways authority doesn't necessarily own the airspace. Is allowing a tree to grow wilful obstruction? If wilful means deliberate obstruction i.e. cultivation or training of a tree with the intended ourpose of creating an obstruction, then no! Trees are treated by the law as unique and different and have been since the foundations of common law in Roman times and probably before then. Again, I agree with your outcome but I harbour reservations about how clear the issue is. And I would suggest that if anyone looks in on this forum and is looking for a yes/no then go carefully because just because branches overhang a road you don't have a TPO exemption automatically to remove them. Firstly you almost certainly have a TPO exemption to remove just enough of them to remove the obstruction. Secondly there could be situations like I know of where a street is only accessible under a 4m railway bridge and it is not imaginable that any vehicle could get there to need 5.2m clearance. No obstruction. Sorry, I am babysitting and bored on a Saturday night, with time aplenty to kill. Please don't lurk in the future, get right in there.

I'm sure we've all been tempted. But who in their right mind would post a video of their own borderline ineptitude or contempt for their client on a public website?

I've wrorn ever to buy ythe Oregon ones again, the spring keeps jumping off or getting bent and not working. The Stihl ones are much much better all round. Even the wood on the handle lasts longer. I have started filing bareback towards the end of the life of a chain. That way you haven't progressively lost the right depth and gone too far into the ties.

You're right, it does have POETS day written all over it.

I agree with Treeseer about malpractice. And a typical cost per tree for surveys (if part of a big survey) is about £2. £4 if you want me to bring a trowel. That said the tree looks pretty humped. But if it's being felled to protect parked cars instead of telling the resident that they have no formal right to park there, it's another small nail in the coffin of civilisation.