Root Protection Area - Installation of dropped kerb

[talljay]

Hi

 

We are applying for a dropped kerb which has the below requirement stipulated by the council

 

Street Trees

If there is tree outside the property then the tree must be assessed according to "Trees in relation to Construction" - recommendations - British Standard 5837:2012 to determine its health and root protection area.

The root protection area (RPA) is a measurement of 12 x the diameter of the base of the tree. This will ensure the continued life and safety of the tree.

Approval will not be given to any crossovers in the RPA of a healthy tree to ensure continued growth and the safety of pedestrians and vehicles passing underneath it.

 

 

We have two existing trees which are positioned as per below diagram. The council are being rigid around the RPA as the "construction" of dropped kerb encroaches around 80mm if positioned directly aligned with existing driveway. I have proposed the below diagram, although I don't have any agreement on this currently as proposals are apparently not part of the process.

 

There has been a significant excavation within the RPA of which I have photographic evidence, along with precedence set within our road of these being permitted previously, however these have been rejected as viable reasons for permission to be granted

 

Moreover my questions are around specifically a proposal of slit trench as the only option given by Council

 

What is the likelihood of roots to be identified when a slit trench is dug at perimeter of RPA calculation - High, Medium, Low ? Or is this not a straightforward answer ?

 

and importantly - what is classified as a root, is there a specific diameter or is it literaly any root identified, whether that be a strand or something more significant.

 

Also are there any other options available that could be suggested over and above 

 

 

We have two trees located as per below diagram - 

 

[AA Teccie (Paul)]

Hello, thanks for your post.

 

Firstly, under the circumstances, I would recommend you appoint an Arboricultural Consultant to advise and assist you with your application for a drop-crossing to your property.

 

Regarding the RPA, circumstantially, given the tree probably isn't 'open-grown' and hence is unlikely to have roots in the highway, they may not consider the simple radius determination to be applicable (the tree is likely to have more significant rooting running parallel with the highway and potentially at greater distance than one might usually expect - often species specific.)

 

In terms of what level of likelihood will there be of encountering roots at the specified RPA radius = 'some' (tree roots are often unpredictable and hence to excavate a (slit) trench is the only way to determine this.)

Regarding what constitutes a root, in this context - usually considered to be anything 25mm dia. or above. 

 

Hoping the above indicates why you need to engage an arb consultant.   

 

Good luck with your application.

Paul

 

PS In terms of where / how to engage a consultant - you can enquire here, you could ask your Council if they can direct you, or you can look here https://www.trees.org.uk/Registered-Consultant-Directory  or here https://icf.datawareonline.co.uk/Directory-of-Consultants

 

 

[daltontrees]

No Council has the right to stick rigidly to the 12x DBH RPA. Trees don't read guidelines, they go where they find favourable growing conditions. The relevant British Standard says tha thte RPS should be drawn initially as a circle, but then should be modified to reflect underground condiitons.

In my experience rooting near roads and footways are nearly never radial. Correction, never.

The Standard says that the assessment of root distribution must be done by an arboriculturist. Neither they with their simplistic rule nor you can justify the RPA being circular or any alternative shape.

Point 2 is that the RPA is not the same as the area within which roots cna be found. The latter is always bigger than the former. A trench may help to demonstrate something or other, and if it showed up no roots then you have the proof you need. If you find roots you don't know if they're important enough to avoid. They might be deep enough to bridge over. Their loss might be tolerable.

Not simple.

 

[talljay]

2 hours ago, AA Teccie (Paul) said:

Thanks for the input

 

Edited August 31, 2023 by talljay

[Kylus Sylvestris]

Why don't you reduce the width of the dropped kerb so it's outside the RPA. You're 4.5m wide access is rather large. 

[donnk]

more bollox from councils. its a dropped kerb couple hundred mm into the ground. not a 3m footing.

 

Shame there is no way to remove these wastes of oxygen from their highly paid unsackable positions.

[Anno]

Nice to wake up from the weekends glorious sunshine to find you are a waste of oxygen.

Also I would take issue with being highly paid after no wage increases for decades under this self serving government, which is why I will need to work until I am 67 (lucky for me there is no chance of getting sacked)

 

Enjoy your day in Narnia Donkk.

[talljay]

14 hours ago, Kylus Sylvestris said:

Why don't you reduce the width of the dropped kerb so it's outside the RPA. You're 4.5m wide access is rather large. 

That’s the minimum the council accommodate - 5 kerbstones, I have proposed 4 and that has been rejected - not policy, even though there are multiple properties in our road with 4 🤷

[talljay]

13 hours ago, donnk said:

more bollox from councils. its a dropped kerb couple hundred mm into the ground. not a 3m footing.

 

Shame there is no way to remove these wastes of oxygen from their highly paid unsackable position

Edited September 4, 2023 by talljay