BS5837 categorisation

[Amelanchier]

Is this apparent discrepancy in 4.4.2.2 really an issue? Do many Arbs, on encountering this conflict sit motionless between the two possibilities like Buridan's ass?

 

It seems to me that the only sensible approach in surveying is to describe the situation as it is when you find it. So either 4.4.2.2 is in error or it should be read as being compatible with the sensible approach. Either way the problem disappears...

[daltontrees]

Ah but the choices are not equal, one interpretation makes more sense than the other, at least I am suggesting that it does. For the meantime it would seem inappropriate for anyone to wholeheartedly claim to have produced a 5837 compliant report. The claim of having followed 5837 would be bearable, since 5837 describes a process as much as it describes an end product.

I can live with the discrepancy and can make sure a client understands what interpretation I have chosen. The difficulty remains that there are trees that cannot be assessed as fitting into one of the codes (A1, B2 etc.). In such cases a caveat that A does not really equal A and 2 does not really mean 2 and Mid Blue really means Light Green is harder to pass off as pragmatism. Or am I making a Buridan's ass of myself?

[ScottF]

The question you should all have in mind is this:

 

"in the case of any "5837 report" (excuse the nested quotation marks) could I defend my approach, whatever it is, to a slavering attack dog of a solicitor in a public inquiry or planning appeal?"

 

From having been through a few of these delightful things, I can say it underpins everything I write.

[daltontrees]

Yeah, been there too... the slavering ones are easy to deal with, just don't get flustered or respond to the aggression. It's the slow measured questioning of Counsel that makes you doubt yourself.

 

Anyway, to tidy up a loose end in my mind, I see that the Categories (A, B etc.) are set up in such a way that I can resolve my asssessment dilemma. The 5837 Categories relate only to two things (i) life expectancy and (ii) quality. The latter is ambiguous. The former is in bands of 'at least [X] years'. So if a tree has say landscape qualities that would put it in the B catergory and make it a B2 (Mid Blue) but has a life expectancy of 40+ years that deserves the A category (Light Green), it can still genuinely be put in the B category because it also (de facto) has a life expectancy of 20+ years.

 

This interpretation taken to its full conclusion is that the tree should be Categorised according to the lower of its life expectancy Category and its Arb/Landscape/Conservation Criterion, all per Table 1. This seems consistent with the thrust of 5837, so we are not bending designs around attractive trees of low life expectancy or hideous ones that will live forever. And whatever 'quality means', if it means health it can be reflected in the life expectancy part of the Category definition and if it means good form it can be reflected in the Criterion definition.

 

That's helped me anyway, sorry if it has confused anyone, if so I can try to explain. I have to tidy it up anyway to add as an explanatory note to my next 5837 report.

[armybloke]

Guys, I would like to chip in on a couple of issues and please feel free to tell me to get back in my box. I admittedly have skim-read quite a lot of the thread and picked out the more important bits (it is all important I know).

 

The first item I picked out was that you should have a tree with 40+ years expected life left to be able to give it an A grade. I gave a 2-300 (ref:Mitchell) year old Horse Chestnut an A only this week. A3 in fact. It is quite exceptional to have a Horse Chestnut live beyond 200 years (in my experience) but as this tree had historical and veteran credentials I applied it in this case. There are exceptions out there and I believe you can use them.

 

The second point I am going to make is that I have been over to the dark side and was a Tree Officer. One comment stated that the task of the TO was to save trees for the community, another comment was that development happens no matter what - I would contest both these points with personal experiences.

 

As TO, I read all of the Arb Reports (AIA and AMS), as did the others in the team that the planning authority placed on the developer as a condition of the planning application. (Developers only ask for consultants help when planning ask for a tree report and quite often developers don't tick the box that says 'are there any trees that will be affected by the development' when it is plain as day that next door has a whopping great tree with an RPA to cover most of the village!). We checked consultants credentials against professional bodies if they claimed to be members and also asked around for professional references from other 'well known' and 'reliable' consultants - there are rouges out there!

 

The arb report was read, maps checked, TPO/CA maps checked and then a report was written about the proposed plan along with the consultants report that went to the planning committee. It was then that all objections were collated, reviewed by a panel and sometimes taken to a public meeting in chambers. Developers DO NOT always get their own way.

 

As a responsible consultant it was only last week that I talked a developer in to not submitting an application on the grounds of protected trees and the difficulty they would need to overcome to build. So even the person writing the report can write it in a positive way but informing their client that perhaps it may be better to seek land elsewhere.

 

As a TO, if trees were involved it was then up to us to TPO a tree if we believed that it would be in the public interest to do so. A TPO is not a constraint in a planning application only a consideration. By way of example; a 60 year old Birch probably has only another 20 years left (location and juxtaposition to solid structures taken in to account) so would you TPO that tree or ask for 2 extra-large standards in return, suitably located with a robust 5 year management plan? You'd TPO the new trees for sure once the management condition you placed on the developer had expired of course. The condition you would also apply is that if the tree died within 7 years you would want a 1 for 1 replacement.

 

The conditions you can apply as a TPO are pretty endless as long as it is endorsed by the planning committee.

 

So back to the 5837 - interpretation is half the battle, but what is key is that it is a guide. So for my ten-penneth, your experience, knowledge (your own and that of others when you ask for an opinion) is vital. Context is what you make of it - will the tree species you are looking at in its current condition (consider hydrology, location, air pollution, prevailing wind, local weather conditions, space to grow, companionship with other trees [think pollination too] and shape) survive within the time spans set out in the BS. <10, 10+, 20+ or 40+ It is a difficult ask but over time I see a tree, look it over for any significant defects (that is another thread for sure) and make a calculated decision. Your report reflects what you see to the TO and planning committee. If you like the look of the tree, where it is and believe its survival falls in to one of the BS categories go with your gut feeling. I reckon 9 times out of 10 you won't have to justify it and if you had to I bet you could!

 

So Paul, going back to your original clump of trees all growing en-mass, all fighting for the same light, nutrients, water and oxygen do you think every one of them will live to the 20+ or 40+ Category you first mentioned? I have not seen the trees and I have no idea on spacing, light, water, oxygen and nutrient availability so you may be right. I am just fuelling your thought response neurones!

[daltontrees]

Tha's a very thorough reply, can't really argue with any of it and I am encouraged to hear that at least some LPAs take it seriously and work through it to get a fair and reasonable outcome.

 

In anticipation that there might be not be much more discussion on this thread, I would summarise by saying that the BS categories don't present a problem, it is what is done with them in the absence of a full understandings of their limitations that could cause problems. And back to teh original post, I would treat the word 'merit' in the same way as I would treat 'quality' i.e. as a floating term that could depict life expectancy OR amenity contribution, and I would now certainly consider the merit in the context of teh proposed use of the site but not the proposed design.

[daltontrees]

Just to clarify that last sentence, an example of proposed use might be 'high density flatted residential development' or '2,000m2 single storey healthcare facility'.

[Amelanchier]

Ah but the choices are not equal, one interpretation makes more sense than the other, at least I am suggesting that it does.

 

As am I! What I mean is that we should take an purposive approach and base our interpretation on a sensible assumption about what the authors intentions were when they collectively wrote the standard.

 

For the meantime it would seem inappropriate for anyone to wholeheartedly claim to have produced a 5837 compliant report. The claim of having followed 5837 would be bearable, since 5837 describes a process as much as it describes an end product.

 

Isn't that just playing with the semantics of 'comply' and 'follow' though? If you follow the process as far as it can be be practically followed isn't your end product compliant with that process in any meaningful sense of the word 'compliant'?

 

As we are aware, the discrepancy is a plain logical contradiction - you can't value the trees in wilful ignorance of a development while considering that development in their valuation. I.e., you can't avoid doing X if you are doing X. To my mind anything that isn't logically possible is automatically irrelevant to the intended outcome of the process - its either;

 

A) a mistake;

B) a deliberate nonsense, or;

C) resolvable by clarification of the terms.

 

If a set of instructions to build a boat had a step that required us to draw a square circle as part of the construction would we say that we weren't compliant if we couldn't draw one but ended up with a serviceable boat at the end of the process? Would that be a useful definition of compliant? Would it be fair to say that the end product was not compliant with the instructions?

 

Pure pedantry of course but then we all need a hobby.

 

I can live with the discrepancy and can make sure a client understands what interpretation I have chosen. The difficulty remains that there are trees that cannot be assessed as fitting into one of the codes (A1, B2 etc.). In such cases a caveat that A does not really equal A and 2 does not really mean 2 and Mid Blue really means Light Green is harder to pass off as pragmatism. Or am I making a Buridan's ass of myself?

 

Not at all, I agree.

Just to clarify, I use the categories much like everyone here following the prescribed criteria to the best of my ability and experience with justification and explanation where appropriate. I just don't rely on the pigeonhole when assessing impacts on the pigeon. TBH I doubt anyone posting on this thread really does but I've encountered it frequently in my previous LPA life.

 

The 2005 incarnation of the standard includes a note to section 4.2.6 (tree survey requirements) that read;

 

"It may be appropriate to assess and list the amenity value of trees as a separate consideration. Various methods have been

proposed as aids to making this assessment..."

 

Thereby recognising the limitation of the categorisation method in reflecting individual variation of amenity. It was and still is common to read that a tree should be removed or retained because it is category A or C. As far as I can see that means very little - it assesses the pigeonhole and forgets the pigeon...

Edited May 24, 2013 by Amelanchier

[kevinjohnsonmbe]

There's a wealth of experience and opinion here. Good thread and fantastic contributions which have been insightful and thought provoking to read.

 

The references to slavering lawyers (as an aside) caught my imagination. Have you guys actually been called in front of a judge, or a planning appeals hearing and been required to account for your findings or are we speaking in terms of the hypothetical potential for that to happen?

[Paul Barton]

Thanks all for your contributions - it's been helpful. I'm more or less going to stick with how I've been this all along: interpreting the BS recommendations as I see they were intended and explaining my reasoning in the reports....although I may add some more reasoning to make my interpretation clear.

 

The issue for me has been working with another arboriculturist (whom I respect 100%!) that has a slightly different approach. Obviously we'll just need to agree our approach when working on joint projects.

 

As yet none of my planning reports have been scrutinised in an appeal situation - so either I've been doing it reasonably well or I've not had any very contentious sites with determined clients! No doubt my day will come so I'll just make sure that I'm ready for it until then...