scotspine1

interesting technology from Beal, the outer sheath is bonded to the inner core making a safer rope in relation to cut and abrasion resistance. [ame= ] [/ame] could suit SRT work positioning what with all the toothed cam ascending, suppose it would depend on other factors but they could be worth a look. I'd never heard of unicore before, seems a good idea. ACCESS 11 mm UNICORE BEAL PRO SEMI-STATIC ROPES - Ropes for difficult area access - UNICORE GINKGO 12 mm - BEAL PRO Semi-static rope - ROPES FOR TREE WORK BAOBAB 13.5 mm UNICORE - BEAL PRO SEMI-STATIC ROPES - ROPES FOR TREE WORK - UNICORE

Was having a wee laugh Reg, Canada has obviously been a great move for you. On a serious note though - surely you waited 4 years because you work in trees and Canada is not exactly short of tree workers? If you are right about it being because you're British and not from Ghana etc then it's probably got a lot to do with Canada being one of the most politically correct countries in the world, they couldn't possibly be seen to be letting more Europeans in could they. They're desperate to lose the 'Great White North' tag

You've moved to a British colony, well done, that's why we set places like Canada, New Zealand and Australia up, to give British citizens options. Well done on moving to BRITISH Columbia. .

good talk here for anyone interested in fungi, skip to 0.27 for start, about 10 mins long. [ame= ] [/ame]

nice vid that Reg. Good camera angles. Job well done. For anyone interested in negative/pole rigging, few clips from a recent Grand Fir we did - it's just the usual stuff but filmed from a nearby tree https://drive.google.com/file/d/0B9UhMrc9u-YVSGJGam5xRWpheU0/view

The problem with his theory is that we've all seen huge included bark unions on mature Beech with no crossing or rubbing branches above the union between the two stems at all. So with this in mind....if you follow Duncan's theory to it's logical conclusion it means at some point in the very early stages of the Beech tree's life the 'natural brace' he talks of will have formed......then it will have created the included bark union, then the two branches that created the 'natural brace' will have died..... yet we see the remaining included bark union created by the 'natural brace' has not failed? so when we look at the mature Beech in question with it's huge included bark union and see there are absolutely no crossing or rubbing branches visible above the union between the two stems we have to ask ourselves - is his theory correct? One thing I have observed in trees is hazard beam or shear failures along branches with a normal U shaped union where they meet the trunk but I've never seen a hazard beam on a branch or stem that has an included bark union because in most cases the high winds will cause it to fail at the fork due to it's comparative structural weakness. .

Interesting Rich. Sometimes you can hit a great union high up in the tree with the bag but you don't always get a good perspective of the leverage you're creating as you ascend up the tree, it's not until you get closer and realise the limb/lead your on is less vertical than you thought - creating a big old lever. Not saying that's what happened in your scenario just an observation I've noticed particularly when setting lines in trees you can't walk round to check angles of anchor points etc or looking up into a crown on a dark winter's day. .

cheers for the reply Reg. All things considered......think it's safe to say a climber should aim to become be proficient in both techniques for work positioning (SRT and DdRT). I've been using SRT with a base tie off for accessing tall trees since around 2001 but I can honestly say despite my best efforts there is something about SRT work positioning with the wrench I simply don't feel comfortable with and probably never will. I'll still use it when I feel it's appropriate though. .

It's heading that way, a la IRATA. A 60m rope will be too short for a groundie to lower you from 90ft in the event of a ground based rescue. .

The most dangerous aspect of SRT work positioning is having a base anchor for the entire period of the work thereby always having to keep track of the down rope and it's route to the base tie off. The climber has to focus on that down line distracting him from the task at hand. Add to that the extra load on the tie in point then compare it to SRT top tie or DdRT and you see you've narrowed the margin for error considerably and increased the variables cancelling out any supposed benefits from the ground based rescue. Quick question on this base anchor thing - Would you consider using two separate SRT lines one tied off at the base and one top tied but both attached to you for the duration of the climb with trailing ends following the same route to ground? Also if you're 90ft up a tree 15ft out on a limb and need ground rescued via a base anchor how long does your rope need to be to get you to the ground safely? . .

Reg, few quick thoughts on the issue................. most of your work involves long ascents and descents which SRT is brilliant for. A lot your work is spiked removals and other than the re-direct limitations of DdRT when compared to SRT I can't see a major advantage in that scenario. SRT is good but there's no way it will replace DdRT wholesale - for most climbers DdRT when not rushed and carried out by an experienced climber is far smoother than SRT, it's 2:1, it's less bouncy, it's better for fine adjustments when getting into a work position, the system tightens easier (easier than a ropewrench set up anyway). Psychologically and visually DdRT will always feel safer than a single line, ok DdRT is still a single line, but it's a doubled single line and for most people that will look twice as safe as a single line especially on a long branchwalk at 70ft. The SRT base tie off for working in a tree is an inherently bad idea, top tie fine. With DdRT every part of the working line is above you and in most situations it's visible, in contrast large portions of a base tie SRT down line are not seen, that's always gonna be a concern........... the ground rescue argument of a base tie off is bordering on pathetic because you're essentially arguing it's safer to climb on a more dangerous system (base tie) because you can be rescued from the ground. I'm not saying you expect to be rescued from a base tie but many people advocating SRT use base tie offs with belay devices whilst working in the tree. SRT is much quicker and more efficent for ascent into big/tall trees no denying that (provided the climber can set a line with a bag within a few attempts). You say you get more work done in a day with SRT, fine now that you're working for yourself, would you say the same if still contract climbing? .

The idea that most mature trees are filled with crossing and grafted branches above included bark unions is utter nonsense. I know this because I spend most days climbing around mature trees. Is the guy Slater proposing that the grafts are created as a result of an included bark union? if so where and how does phototropism fit into that theory? It also implies the tree is a sentient organism which aware of where each branch is located. Not really common sense, more common knowledge amongst experienced tree workers, but more so because if you remove one of two grafted/ crossing branches the retained branch is more likely to fail. It's also why 'crown clean' was removed from the most recent BS3998. The thing is - most experienced climbers would never remove large crossing branches in a mature beech for example even if they saw the words 'crown clean' on the spec. The removal of 'crown cleaning' from most recent 3998 was based on the idea that tree surgeons are too thick to make an informed decision about wether or not to leave large crossing limbs (and the deadwood issue) .

If you look at the lower right drawing of the longitudinal crack, assume you've removed both heads of the stems and cut below the union so all you have left is what is shown in the diagram, in my experience the saw will often jam if you try to cut through parallel to what Mattheck is calling the lower crack front - this happens because of the compression, have seen it in both conifer and deciduous species, Lawson Cypress and Beech for example. Will try to get a vid and post on this thread.

my experience of working in trees with co dom included bark unions tells me that once the weight is removed above the union you can often see the two stems sitting closer together, in fact I've seen a climber get his foot jammed as the space between the stems closed after he removed a head above the union. Often see the saw jamming in the cut if it's started from the outside of the union as the compression from the other side forces the other stem down on the bar of the saw. The way round that is to bore into the centre of the union and cut outwards.

there's compression in a compression fork pushing the two stems towards each other, who ever said there was a compressive force pushing them apart? .

the climber at 8.52 on the single line, what's he using?

true, but if a few hundred labourers in India can dismantle a colossal tanker by hand.........surely 3 or 4 tree guys in the UK can dismantle and shift a single tree out of a back garden.......

Good job, great vid.

First Aid Kit is better than ArbAid [ame= ] [/ame]

both - accident on ascent for example......or moving around between cuts for 65ft the answer is 200ft or just over 3 times the length from access branch/tie in point to ground. ..

not if he was moving around the canopy between cuts

If you set a line at 65ft for SRT with a base anchor that could be used in the event of a ground rescue - how long does the rope need to be to get the climber to the ground safely?

SRT work positioning developed/evolved mainly in the US over the last 10 years. Morgan Thomson's Unicender appears 2005/6 allows up/down movement on a static line. Treebuzz members Tom Dunlap, Rich Hattier, Moss and a few others experiment with SRT work positioning from 2006 onwards, posting pics and discussing ideas mainly at Treebuzz. Kevin Bingham introduces the F8 Revolver on Treebuzz around 2008, work positioning on a single line with the idea of adding extra friction for a smooth descent, from there Bingham develops the Ropewrench, first one is made of wood (2009/10) this is when the wrench idea clicked for a lot of folk who'd been puzzled by the F8 Revolver. From there Bingham introduces the steel Ropewrench, then the ISC version appears couple years later. SRT work positioning with Ropewrench is allowed in ISA comps from 2014 onwards.

Paul, good to see you on the thread and get your input. I think you've made it clear where you stand on the responsibility for the incident, helps clear things up for a lot of people in relation to the limits of the AAAC/ArbAC scheme. Cheers for that. .

bad example as the doctor or nurse are normally struck off by the awarding bodies and relevant medical assessors never to work again in the health service.