Ash dieback and development sites

[Paul73]

I have been engaged to get involved in a no doubt heated debate over a development site on which there are a large number of self sown Ash trees. I feel like I would do well to know what has been said by any government funded bodies about Ash dieback, its projected speed, and how that might impact on the concept of a tree needing 10 years of useful remaining contribution to be worthy of retention on a development site.

 

The trees in question are on derelict pasture, mostly 25 years old or younger. Some road-side trees were recently felled under section 211 notification because of Ash dieback. Every tree on site shows some signs of Ash dieback but most are in stage 1 with only one very large old one being in stage 3. 

 

Can anyone suggest a reading list to me? Any planning policy documents I should be looking at? Any sources for the thinking behind the 10 years in BS5837 what reasons did they give for saying it? I always assumed it was not to saddle new home owners with problem trees.  

 

Cheers,

 

Paul

[AA Teccie (Paul)]

reading opportunities (many) including:

https://www.gov.uk/guidance/managing-ash-dieback-in-england

 AshDieback-GuidanceNote-web.pdf

 

The situation you describe is not uncommon and one would hope for pragmatic solutions with the LPA...good luck.

[Paul in the woods]

When I last trawled through the various documents from the likes of what is now Forest Research it seemed to be non-conclusive, so you could build a case for keeping or removing the trees.

 

I own a few acres of young ash, so over 1000 trees. They are about 30 years old and I've watched them over the years catch and die from die back. The last few years I've marked trees in the summer that show obvious crown die back so I can tell in the winter which ones I need to remove. Some I've not got round to felling but it identifies the badly affected trees for the next year. Typically they decline and die in a couple of years, I've left a few to provide dead standing timber but they are now falling over after just a year.

 

Your site may well be different but I wouldn't of thought it would be worth keeping any trees with signs of dieback.

[daltontrees]

I have thought about this long and hard and looked everywhere for guidance, and there is none.

The appropriate thing to do, therefore, is to fall back on first principles. The BS5837 Estimated Remaining Contributions bands are fairly arbitrary, but I advise clients to think in terms of  the design life of their development. Housing is typically 40+, and so any tree that can be kept to provide amenity in that context is rightly an A. Bs that have ERC of 20-40 or BS that have 40+ but are imperfect specimens can make a contribution to amenity for a large part of the design life, and most LPAs will also look for them to be retained where possible.

The difficulty comes at the low end of the scale, Cs and Us. What it is important to remember that although U stnads for 'Unsuitiable for retention' this is a rather inappropriate abbreviation of what U really means, namely of such low quality and short ERC that they should not prevent development of  a long design life. It doesn't mean they can't be kept. And also this does not mean no trees, it usually means a requirement for tree amenity in the site somewhere else though landscaping obligations.

So when can they be kept? When they are in a position that allows them to remain without being a risk due to targets and/or size. Design adjustment might or might not allow some to be kept. It's worth considering sometimes.

It would I think be unreasonable for a LPA to refuse PP on tha basis of tree loss where the trees are going to be lost to natural causes anyway. In an extreme example, a site of only ash could be effectively treeless in 10 years and there is no legisalation anywhere that can force an owner to replant it (unless there is a planning application). So the smart solution for applicant and LPA is to achieve net gains by appropriate structured landscaping with trees.

 

The distincton between C and U in terms of years is a little arbitrary. More important is that Cs are defined by their impaired condition and lack of merit but Us are defined better, by -

"Those in such a condition that they cannot realistically be retained as living trees in the context of the current land use for longer than 10 years" because they are one or more of  -

(i) Trees that have a serious, irremediable, structural defect, such that their early loss is expected due to collapse, including those that will become unviable after removal of other category U trees (e.g. where, for whatever reason, the loss of companion shelter cannot be mitigated by pruning)
(ii) Trees that are dead or are showing signs of significant, immediate, and irreversible overall decline
(iii) Trees infected with pathogens of significance to the health and/or safety of other trees nearby, or very low
quality trees suppressing adjacent trees of better quality
NOTE Category U trees can have existing or potential conservation value which it might be desirable to preserve. 

 

The key words in there are that it is the 'current' land use, that decline is 'irreversible'.The 10 years arbitrary ERC only really makes a distinction on rate of decline.

 

So for youg ash, there is little point in anyone arguing for their retnetion, especially if the context of development allows for sustainable planting. But for older ash the case is not so clear, they can carry on for years and there are (rare) examples of them recovering. Marginal cases coudl be kept in less trafficked parts of a site.

The categorisation should NEVER be justified by the proposed usage of the site. Wanker reports that justify removal on the basis of proposed development are just that!