Holding back the years.........

[Gary Prentice]

Yes 11mm.

we have 2 lines for SRT.

1 is 60m & the other I think is 80m

 

On that particular job it may have been a beter option to have had a (tensioned) top line anchored at the top of 2 adjacent trees with a floating work anchor running on that.

Rather than the set up we used of running from the top of one (through the pollard canopy) to the base of the other.

 

 

 

 

 

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I was involved in mountain rescue until a few years back, so out of academic interest, I'm trying to calculate the forces and loads imposed by the zip line.

 

Cheers, it's really interesting to see environmental arb so well documented.

[JonnyVine]

Fascinating thread David, loving every minute

[David Humphries]

The site was used as a set for the forest scenes (supposedly Sherwood) during the filming of Robin Hood, prince of thieves in 1990.

 

 

 

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[David Humphries]

The site was used as a set for the forest scenes (supposedly Sherwood) during the filming of Robin Hood, prince of thieves

 

The last image above is of one of Burnhams most iconic trees, the cage pollard

 

Here it is over the last few years after the filming & having had a mewped reduction during the back end of last year.

 

 

 

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[David Humphries]

No longer? One of my favorite pics is Jason Gairn standing next to a 3m rip.

 

Only a very distant vague memory of that one, any pointers as to where it was?

 

 

I recall this one going ballistic when it popped orf

 

 

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[Arob]

Helen has said she will do a brief piece for this or another related thread regarding the training. My understanding is that it will be available on the net at some point.

 

Hopefully will get to see some of that footage soon.

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The session has focused me and the team to look into going down the helmet cam route.

 

Not entirely sure what your asking regarding working on lapsed pollards?

Do you mean here in the UK or further afield?

 

Just thinking in the UK, i have a new customer who appears to be happy to commit to annual work carried out on a dozen or so trees including a couple of large "pollards" (i.e. topped Pops) and some topped sycamores, having only been picking up bits and pieces of tree work over the past couple of years i was looking to reinforce my understanding of the subject.

 

We have half a dozen sycamores each with differing levels of damage, and with differing requirements, one we hope to 'rescue' by thinning out and allowing a new multi-stemmed crown to develop, another we will thin only because the better option of reducing is not possible due to the lack of leader and hence anchor points (discounting a MEWP on cost grounds). For a further three very ungainly trees forming a line on a boundary we need to balance amenity value against risk, my proposal is to reduce these to an even height and then manage the regrowth on an annual basis with the longer-term goal of selectively pollarding on a 6 year rotation or thereabouts in order to maintain a constant crown cover (so removing stems equal to one sixth of the total canopy each year - targeting the largest stems). The last tree we will lightly reduce to clear property, remove stubs and thin some of the low regrowth.

 

So much of that is straightforward, the main thing i'm looking out for is reference to selective pollarding (thinning) on various cycles, i wonder whether there is a direct relationship between cycling and wound healing - the developed pollard heads of annually pollarded trees suggest to me that numerous small shoots may wall out decay more effectively than fewer larger stems - but i have not evidence in support of this. A further question is to do with the secondary reduction of large stems on a 'topped' tree either to re-establish form or to remove decay, as many people don't want to lose large trees - even if they are misshapen and compromised by 'topping'.

 

Given the huge potential demonstrated by sites like Arbtalk and new opportunities such as GoPro's (i've learnt a lot from a few short Reg Coates films), and given our legacy of topped trees and lapsed pollards in gardens and streets i wonder whether there isn't scope for something which not only aids the understanding of the occasional tree worker such as myself, but also that of the layman such as my customer.

 

But as i say such things may already exist and my lack of knowledge be a lack of my own efforts to research.

 

Phew!

Edited February 10, 2013 by Arob

[David Humphries]

given our legacy of topped trees and lapsed pollards in gardens and streets i wonder whether there isn't scope for something which not only aids the understanding of the occasional tree worker such as myself' date=' but also that of the layman such as my customer.

 

But as i say such things may already exist and my lack of knowledge be a lack of my own efforts to research.:[/quote']

 

As mentioned earlier in the thread, it may be worthwhile in you getting hold of the next issue of the Arb Journal. Although specifically concerning beech, the overriding principals of working on lapsed pollards in terms of tree vitality, timing, decay and size of reduction are covered in the study and report.

 

 

 

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[agg221]

Hi David,

 

I've never visited this site, but one aspect has me intrigued.

 

At the moment, you are managing a gradually dwindling stock of pollards, which host a range of rare species. The younger beeches do not appear to be pollarded.

 

Although the work you are currently doing is designed to hold back the years so far as possible, I wondered what the succession plan was, long term. This had me thinking in parallel with the other current thread on the subject of pollard creation. Are you creating new pollards at all, and if so, are you doing so only from small trees, in line with the applicable BS, or are there any plans to try creating some prematurely veteranised pollards, to accelerate generation of host habitat? I'm thinking of things like the image of the topped beech which you put up earlier in the thread, for example, which looks like it could be gradually lowered to 'classic' pollard height, and given the large central cut, should rot out fairly quickly.

 

Just interested in the long-term plan.

 

Alec

[Arob]

Thanks David, looks like it's time to renew my AA membership!

 

(So as not to further derail i'll post this link to another pollarding thread which fills some of my research gaps http://arbtalk.co.uk/forum/tree-health-care/54050-pollards-leave-fingers-not.html)

[David Humphries]

Hi David,

 

I've never visited this site, but one aspect has me intrigued.

 

At the moment, you are managing a gradually dwindling stock of pollards, which host a range of rare species. The younger beeches do not appear to be pollarded.

 

Although the work you are currently doing is designed to hold back the years so far as possible, I wondered what the succession plan was, long term. This had me thinking in parallel with the other current thread on the subject of pollard creation. Are you creating new pollards at all, and if so, are you doing so only from small trees, in line with the applicable BS, or are there any plans to try creating some prematurely veteranised pollards, to accelerate generation of host habitat? I'm thinking of things like the image of the topped beech which you put up earlier in the thread, for example, which looks like it could be gradually lowered to 'classic' pollard height, and given the large central cut, should rot out fairly quickly.

 

Just interested in the long-term plan.

 

Alec

 

Hello Alec,

 

a very good point and not one I'm qualified to answer specifically as It's not my site (although we have created a few new pollards over the last 5 years we've been working there), i'm not privy to the management plan regarding pollard ecology succession other than knowing that Burnham lose on average 6 old pollards every year through snow loading and meripilus & ganoderma decay.

 

I'll try and find out how many 'new' pollards are created each year & how long that has been going on.

 

The b&w shot below is of one of the largest pollards that used to be at Burnham, now sadly gone.

 

 

"The restoration work on the old trees has been evaluated and the responses of the trees examine in detail. The annual mortality rate has slowed for the beech pollards from 1.91% prior to 1999 to 1.69%. However it is estimated that it needs to still further to 1.3% per year or less. If this situation does not improve by 2080 there will be less than 100 of the ancient pollarded beech trees remaining. In the course of evaluation the importance of leaving long stubs has been shown. General arboricultural techniques target prune and leave no stubs when the branches are cut. Beech pollards clearly produce more new shoots after cutting if they have stubs of ideally at least 0.5m left between the point of cutting and the first retained branch. For more information about the detailed responses see Read et al. (2010)."

 

There were once 3000 pollards at the site, but down to around 450 now.

 

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