bs5837

[tree79]

Hi all,

 

Can you off set the rpa on a bs5837 report?. I know it was in the old bs, but it doesn't state you can or cant in the latest bs.

Just wondering as I recently was asked to carry out a report, but the rpa is with the planned development,(which is a extension to an outbuilding).

The old rpa offset would have been enough to make a difference.

 

any help is always greatly welcomed

[kevinjohnsonmbe]

does para 4.6.2 help?

[slack ma girdle]

Can you dig a couple of test pits to see the extent of the roots ?

Is the RPA going to be compromised by more or less than 20 % ?

[tree79]

does para 4.6.2 help?

 

a little yes thanks,

I will have another look at the project.

[tree79]

Can you dig a couple of test pits to see the extent of the roots ?

Is the RPA going to be compromised by more or less than 20 % ?

 

not able to dig test pits, the rpa would be compromised by any then 15%

[Jesse]

Hi all,

 

Can you off set the rpa on a bs5837 report?. I know it was in the old bs, but it doesn't state you can or cant in the latest bs.

Just wondering as I recently was asked to carry out a report, but the rpa is with the planned development,(which is a extension to an outbuilding).

The old rpa offset would have been enough to make a difference.

 

any help is always greatly welcomed

 

Yes, both regs are RECOMMENDATIONS as long as who ever produces the report can quantify there report recommendations / specifications and can clarify any questions raised by planning i see no reason why not. Remember the original 5837 20% rule only apply d to single trees , but i would take into account every conceivable consideration as being worthy . Historical trenches , surface coverings , ponds, existing structures, waterways , and ground level . Consider everything not just whats specified within the 5837's .

[daltontrees]

As kjmbe has identified, para 4.6.2 seems the relevant one. The key is that anything other than a circular RPA has to be justified on the basis tha the roots are offset. There is no basis for moving the RPA sideways if the rooting is in fact circular.

 

BUt that's only what BS5837 says the constraints are. If someone suitably qualified/experienced can make a case for offset to the planners on the basis that adequate rooting is remaining to ensure the ongoing vitailty of the tree, thsen this should be done after and separately from the survey and rpa calculation.

 

So, don't try to pretend an offset is a genuine RPA. Better to say it's not, but then go on to justify why it's enough rooting volume to ensure ongoing vitaility.

[Chris at eden]

I had one passed recently by Birmingham City Council when a proposed extension was cutting into just over 10% of the RPA. I didn't even bother to offset, i just sold it to the LPA that such a small area incursion would not be an issue as on the opposite side was a public open space which would be a better rooting environment. I also advised that the foudations within the RPA must be dug by hand and under supervision. No roots over 25mm to be severed, trech lined to protect roots from concrete, etc. The tree is a mature oak with a TPO, and is located on the council open space.

 

I would not have tried the same approach if the opposite side was an engineered highway as i doubt i would have got away with it and i dont like getting negative comments back. Plus it would be unprofessional which i dont like either.

 

Horses for courses.

[tree79]

Thanks all for your advice, iyts a great help

[Andy Clark]

I think the point that's been missed on this thread is that is modification of the RPA actually down to you to determine?

 

Don't get me wrong, we don't know the spec of your survey brief, so it may be the case that you've been asked to give such info, bit if not, and you've just been asked to carry out an impact assessment and do a tree constraints plan, then of course you are only really there to report on the trees that are on site from a purely factual and unbiased perspective.

 

RPA modification is something that you could cover in secondary info, such as within an Arb method statement, and then be left up to the architect/engineer/planner to argue.

 

I guess what I'm trying to say is just be careful that you're not getting drawn into acting outside of your remit, and inavertantly get embroiled in the stuff that should/could be down to the other parties in the development process.

 

I know of several 5837 surveys that have been rejected by LPA's, purely on the basis that the arb surveyor was clearly not impartial within the report.