BS5837 categorisation

[ScottF]

It does, thanks Scott. As it happens the Birches I looked at where 650mm DBH and 20 metres tall - lovely trees but in my opinion unlikely to exceed 20 years further.

 

Hi Paul- my point was- how long is the development going to be there before it's bulldozed and replaced with something else?

 

I might have a root around and see if there's any data on this, as my experience is that while you sometimes see older buildings (Victorian schools etc) being demolished and replaced, I far more often see buildings of less that 40 years old coming down. With that in mind, what relevance has the lifespan of 40+ years for an A tree got, when a tree which is already in middle age, or a fast-grower which will mature during the development "lifespan"?

[oslac]

It does, thanks Scott. As it happens the Birches I looked at where 650mm DBH and 20 metres tall - lovely trees but in my opinion unlikely to exceed 20 years further.

 

Hi Paul- my point was- how long is the development going to be there before it's bulldozed and replaced with something else?

 

I might have a root around and see if there's any data on this, as my experience is that while you sometimes see older buildings (Victorian schools etc) being demolished and replaced, I far more often see buildings of less that 40 years old coming down. With that in mind, what relevance has the lifespan of 40+ years for an A tree got, when a tree which is already in middle age, or a fast-grower which will mature during the development "lifespan"?

 

 

 

The LPA can only look at 'what is' and not 'what maybe'. If it is intended that the development has a life of less than 40 years and the LPA conditions the approval to this effect, you may have a point. This has been the case recently where I acted for a solar farm with a planning life of 40 years. At the end of this period, the developer will need to go back to the planners for an extension of time or remove the developemnt and reinstate to pasture.

 

In normal planning situations, no LPA will condition a building for any maximum time frame. Remember we have prefabs built after the war and meant to last less than 10 years and which are still lived in over 60 years later. If an owner wishes to demolish their building, they don't even need planning permission but any new development (permitted development excepted) should consider the material elements i.e trees and ecology when determining the application.

[jaime bray]

Quite. The clue is in the title isn't it: 'recommendations'. I realise that you can write anything you want in a report so long as you can justify it. What prompted the thread was just the recent experience of working with another arb that has a slightly different approach.

 

 

 

Ditto.

 

 

 

 

It does, thanks Scott. As it happens the Birches I looked at where 650mm DBH and 20 metres tall - lovely trees but in my opinion unlikely to exceed 20 years further.

 

Place them in B3. I seem to remember the category C3 also was regarded as trees with ecological value if retention was not 20 years. But that is not documented, purely discussion.

 

One thing that does become apparent is that as long as you can defend your decision then it is not an issue. If you placed said trees in B2 and it went to appeal and you said well the trees are of significant contribution to the wider landscape at present, than other trees on the site with little or no landscape contribution and they were 'merely' selfsets of reasonable quality would that not alter the categorisation' and possibly place said sycamore in Cat C justifiably? Seems to me that you would be showing consideration for trees in there current setting amidst the immediate landscape area and that of the wider.

 

Its hard to comment on such things when the site has not been seen in my opinion.

 

Justification to any decision is key.

Edited May 21, 2013 by jaime bray

[oslac]

Trees are not placed in the category you want them to be in. Their grading is based on a cascade chart whereby all trees start off being checked as to whether they are unsuitable for retention. In other words, trees with a remaining contribution of less than 10 years are categorised as U.

 

All other trees to be considered for retention are placed into the A category. If they do not fulfill the criteria for A category (qualitative and remaining contribution), they drop to a B category. If they do fulfill the requirements for A category, then they remain an A category.

 

If trees do not comply with the qualitative and remaining contribution of a B category, they drop to a C catagory. If they do fulfill the requirements for B category, then they remain a B category.

 

 

In BS, there is no provision to slot a tree into any particular or preferred category.

[Paul Barton]

Hi Paul- my point was- how long is the development going to be there before it's bulldozed and replaced with something else?

 

I might have a root around and see if there's any data on this, as my experience is that while you sometimes see older buildings (Victorian schools etc) being demolished and replaced, I far more often see buildings of less that 40 years old coming down. With that in mind, what relevance has the lifespan of 40+ years for an A tree got, when a tree which is already in middle age, or a fast-grower which will mature during the development "lifespan"?

 

Interesting point Scott, and you are right about the amount of re-development of relatively young sites. Perhaps because the planning system made so many failures in the 70s and 80s...hopefully it will work better for new developments now?!

 

Either way, to use my assumption on the lifespan of the development in order to help choose which trees to retain seems to be stretching the arb's remit a bit.

[Paul Barton]

Place them in B3. I seem to remember the category C3 also was regarded as trees with ecological value if retention was not 20 years. But that is not documented, purely discussion.

 

One thing that does become apparent is that as long as you can defend your decision then it is not an issue. If you placed said trees in B2 and it went to appeal and you said well the trees are of significant contribution to the wider landscape at present, than other trees on the site with little or no landscape contribution and they were 'merely' selfsets of reasonable quality would that not alter the categorisation' and possibly place said sycamore in Cat C justifiably? Seems to me that you would be showing consideration for trees in there current setting amidst the immediate landscape area and that of the wider.

 

Its hard to comment on such things when the site has not been seen in my opinion.

 

Justification to any decision is key.

 

Great comments, thanks Jaime.

 

I didn't really intend for the thread to discuss specific sites, just wanted to give an example but it may not have helped!

[Amelanchier]

I don't see BS5837 categorisation as that important, it's simply a mechanism to add value information to your dataset (i.e., is it a decent tree? If so - what's decent about it?). So the categorisation is as relevant as your argument needs it to be.

 

Clearly an AIA needs some sort of value data because you can't usefully weigh the future impacts on an asset without first establishing it's existing worth (though I've seen it tried). Of course you then need to explain your framework for making those judgements - the BS categorisation is just an attempt to unify that explanation to create, well, er, some kind of standard...

 

to that end I feel obliged in my reports to describe the current and future amenity that the trees provide to the area at length within the text, so I don't feel so beholden to the categories. As a result I can't say I fret to much about whether a given tree is an "A" or a "B1" because if its an important tree within the scheme then I'll have identified its particular merits and limitations anyway. I find that it is much clearer to make an argument about retaining trees because they "...provide significant scale and mass which breaks up the predominantly built skyline that forms a backdrop to the views of the site from the northwest..." rather than because they "are of category A2". Tends to be the way PINS inspectors phrase things to - jargon free and specific.

 

I'm always rather pleased to see consultation feedback comments which dwell on categorisation (or any other immaterial detail). To my mind it means the argument is so well made that the consultee is left with nothing that matters.

[Amelanchier]

In BS, there is no provision to slot a tree into any particular or preferred category.

 

Except that in the foreword we have the following [my emphasis in bold];

 

"This British Standard takes the form of guidance and recommendations. It should not be quoted as if it were a specification and particular care should be taken to ensure that claims of compliance are not misleading.

 

Any user claiming compliance with this British Standard is expected to be able to justify any course of action that deviates from its recommendations."

[oslac]

Except that in the foreword we have the following [my emphasis in bold];

 

"This British Standard takes the form of guidance and recommendations. It should not be quoted as if it were a specification and particular care should be taken to ensure that claims of compliance are not misleading.

 

Any user claiming compliance with this British Standard is expected to be able to justify any course of action that deviates from its recommendations."

 

The meaning of the term specification relates to the document as a whole, not the individual elements within it. In other words, it would not be wise just to say all development to comply with BS5837:2012.

 

If you are claiming that your tree report is BS 5837;2012 compliant and it is not, you must justify how/why your report is not compliant. If your report deviates so much from the BS then it might be said that the report is no longer a BS5837 report.

 

You may re-write the categorisation methodology but it is a significant part of the BS and as such, are you really providing a BS report or a version of your own report. There is ample provision within the AIA to give reason/justification why a tree should be retained/removed irrespective of whether it is an A, B or C category tree/group

[Paul Barton]

I don't see BS5837 categorisation as that important, it's simply a mechanism to add value information to your dataset (i.e., is it a decent tree? If so - what's decent about it?). So the categorisation is as relevant as your argument needs it to be.

 

Clearly an AIA needs some sort of value data because you can't usefully weigh the future impacts on an asset without first establishing it's existing worth (though I've seen it tried). Of course you then need to explain your framework for making those judgements - the BS categorisation is just an attempt to unify that explanation to create, well, er, some kind of standard...

 

to that end I feel obliged in my reports to describe the current and future amenity that the trees provide to the area at length within the text, so I don't feel so beholden to the categories. As a result I can't say I fret to much about whether a given tree is an "A" or a "B1" because if its an important tree within the scheme then I'll have identified its particular merits and limitations anyway. I find that it is much clearer to make an argument about retaining trees because they "...provide significant scale and mass which breaks up the predominantly built skyline that forms a backdrop to the views of the site from the northwest..." rather than because they "are of category A2". Tends to be the way PINS inspectors phrase things to - jargon free and specific.

 

I'm always rather pleased to see consultation feedback comments which dwell on categorisation (or any other immaterial detail). To my mind it means the argument is so well made that the consultee is left with nothing that matters.

 

Thanks for chipping in Tony. I agree with you but am cynical (realistic?!) about how much of the report gets read!

 

Isn't there always a danger that the architect/developer just views the pretty coloured trees on the plan and begins eliminating them from there, starting with dark reds and moving on to greys then blues?

 

I guess it's not our fault if people don't bother to read what is written down though....