UKTC Archive

RE: AAGN12 - Guide to the use of cellular confinement systems near trees

Subject: RE: AAGN12 - Guide to the use of cellular confinement systems near trees
From: Jim Quaife
Date: Oct 29 2020 11:09:15
We have built up layers of cellweb to compensate for side-slopes ever since 
it was introduced.  We also worked with an engineer to solve the problem of 
keying stone kerbs.  Installed properly cellweb has a good degree of lateral 
retention, but the worst problem is block pavers on curves shifting sideways 
due to the scrubbing effect of tyres.  The kerbs have to be able to resist 
that force.
As a more general observation, we take account of a tree's full rooting area 
(inevitably an estimation) because the focus on the RPA alone ignores root 
morphology.
I am happy with the concept of the RPA and yes roots tend to be concentrated 
near the surface (although the mass proportion of the deeper roots does need 
to be a consideration - subsidence anyone?) but what's wrong with a trial 
hole or two?
I might be a dinosaur but I can still wield a digging chisel and shuv-holer!
What I like about this guidance is that it provides the technical 
explanations of the various factors.
Most no-dig installations are relatively straightforward, but where 
modifications are necessary the tech stuff is invaluable for justification.
Jim 

Pressure-washing the surface every year?  Derek Patch's response to that - 
"yeah, that's going to happen!"

-----Original Message-----
From: uktc-request@xxxxxx.tree-care.info 
[mailto:uktc-request@xxxxxx.tree-care.info] On Behalf Of Jerry Ross
Sent: 29 October 2020 10:45
To: UK Tree Care
Subject: Re: AAGN12 - Guide to the use of cellular confinement systems near 
trees

Useful to have a guide to supersede the venerable APN12!
I'm not sure about the way it deals with uneven ground though, by piling up 
sharp sand or clean angular aggregate to fill in the dips. (par. 17, p9). A 
colleague of mine (who has laid acres of the stuff) recommends laying the 
geocells directly onto slightly uneven land and levelling
*above* the cells, and where there are deeper hollows, using thicker or 
doubling up the geogrid, as in the diagram attached.
It seems to make good sense to me to put the additional stone *above* the 
protective layer, not below it.



On 27/10/2020 14:32, Ben Rose wrote:
The new good practice guide for the use of cellular confinement systems 
near trees is now available. For those unfamiliar with cellular confinement 
systems, they can be used as temporary ground protection or to create 
low-impact surfacing near trees.

A free download of the document is available on the Arboricultural 
Association 
website:https://www.trees.org.uk/News-Blog/Latest-News/New-guide-to-us
e-of-cellular-confinement-systems-n

I hope that you find this guide to be informative and of assistance.

Best regards,

Ben








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