Mislabelling Bristol’s crucial open spaces as “brownfield” sites to justify development

A recent landmark Council motion to Protect the Green Belt and Bristol’s Green Spaces, was approved with cross-party support and no dissensions. As a result, vital green spaces within Bristol now have additional protection, in line with the City’s declarations of Climate and Ecological Emergencies, the recently published Ecological Emergency Action Plan and the new Environment Act 2021.

However, a consequence of the adoption of this motion is that there is greater pressure to develop on  other sites.  Those advocating development on open spaces within Bristol have begun, arbitrarily and without proper justification, to declare such open spaces to be brownfield. To inaccurately describe a development site as brownfield places Development Committee members under undue pressure to approve a planning application when, as greenfield, a site should fall under the additional protection engendered by the landmark motion.

Baltic Wharf Caravan Park

Recent examples (see below) where the term brownfield has been misused  are the Bristol Zoo Gardens car park on College Rd, Clifton and the Baltic Wharf Caravan Park on the Floating Harbour in Hotwells, each of which have been mislabelled as brownfield sites despite not falling within with the recognised legal definition.

Bristol Zoo Gardens car park

The term brownfield site is used to describe certain types of previously developed land. Most dictionary definitions refer to this land as being currently or previously occupied by a permanent structure which generally includes the potential for contamination. In planning law there is a definition which must apply when considering planning proposals. This is detailed in the National planning policy framework (NPPF – called ‘Previously developed land’, p.70) as:

Land which is or was occupied by a permanent structure…. and any associated fixed surface infrastructure”.

The definition excludes land which is maintained as a garden:

….. land in built-up areas such as residential gardens, parks, recreation grounds and allotments…

In addition to the definition, there is a statutory requirement for local authorities to maintain an up to date register of brownfield sites which are appropriate for development:

Regulation 3 of the Town and Country Planning (Brownfield Land Register) Regulations 2017 requires local planning authorities in England to prepare, maintain and publish registers of previously developed (brownfield) land”.

Brownfield land registers will provide up-to-date and consistent information on sites that local authorities consider to be appropriate for residential development having regard to the criteria set out in regulation 4 of the Town and Country Planning (Brownfield Land Register) Regulations 2017.” 

“Regulation 17 requires local planning authorities to review their registers at least once a year“.

The Town and Country Planning act also addresses the situation where a fragment of the site might be considered brownfield, but other parts of the curtilage is green space:

Greenfield land is not appropriate for inclusion in a brownfield land register. Where a potential site includes greenfield land within the curtilage, local planning authorities should consider whether the site falls within the definition of previously developed (brownfield) land in the National Planning Policy Framework. Where it is unclear whether the whole site is previously developed land, only the brownfield part of the site should be included in Part 1 of the register and considered for permission in principle”.


Mislabelling as brownfield examples in recent planning applications

Bristol Zoo Gardens car park, College Rd, Clifton (21/01999/F)

The planning proposal makes the statement “The application site is brownfield, previously developed land, as it is a car park“. Mayor Marvin Rees similarly defined the site in a subsequent tweet criticising some members of the Development Committee for voting against the proposal.

This site fails to comply with the proper planning definition of a brownfield site. In relation to the NPPF definition, 7.4% of the site is occupied by buildings whereas tree canopy covers about 17% of the site. Much of the site is covered by unfixed surface, which does not qualify under the definition of a brownfield site. Therefore, according to the Town and Country Planning Act only 7.4% of the site could be considered brownfield, with the remaining 92.6% being classified as greenfield. The site does not appear on the Council’s register of brownfield sites, and therefore cannot legally be classified as such.

Baltic Wharf Caravan Park (21/01331/F)

This planning proposal has also been inappropriately described as a brownfield site in the planning application. Only 2.6% of the site is occupied by a permanent structure, whereas the 100 trees that occupy this site cover over 30% of its area. Thus, only 2.6% of the site could possibly be defined as brownfield, with the remaining 97.4% falling under the classification of greenfield. Furthermore, as much of the site is maintained as a “residential garden”, the site is exempt from the NPPF definition. This site, also, is absent from the necessarily up-to-date register of brownfield sites.

Whilst there may be arguments to develop some parts of some of these sites, the existing trees should be retained in order to comply with Local Planning Policy BCS9.  The current approach  of flattening all trees, including those  on the edge of the site results in third rate developments.  Instead, new developments should be built around existing trees.


Petition

If you agree that this mislabelling should stop, please sign this petition to protect Bristol’s green spaces from the Council’s mislabelling of them as “brownfield sites”:

Protect Baltic Wharf and Bristol’s Other Green Spaces

Baltic Wharf Caravan Park: a controversial planning proposal

We have never been able to understand why Bristol City Council decided to terminate the lease of the longstanding and very successful central Bristol caravan site. It is not a brownfield site crying out for redevelopment, as some would have us believe. Its success and the 91 mature, well-established trees that grace it (74 of which are to be removed) testify to that.

Bristol Chamber of Commerce has described this caravan park as ‘… an important, high performing asset for Bristol’s visitor economy, enabling visitors to stay in walking distance of the city centre and thus providing significant levels of custom for local businesses‘.

And John Hirst, as Chief Executive of Destination Bristol, observed that ‘There are significant financial benefits for Bristol due to the year round supply of visitors to their current caravan site. We know that the current Bristol site at Baltic Wharf has been one of the most popular and successful central sites in the UK’.

So why on earth close the caravan park for a plan that almost nobody really wants – at least 273 at the last count? It seems that it’s worth closing this successful tourist attraction to replace it with new housing, even though the caravan park is estimated to bring some £1 to £1.5 million annually to Bristol’s tourist economy. The scramble for new housing at any cost – while ignoring the wishes of local communities and the economic benefits that the caravan park brings us – seems to take priority over all else.

And the result? We have proposals that will flatten every inconvenient tree rather than incorporating them into the proposed development. This only adds to the steady loss of green spaces and reduces Bristol, especially the centre of Bristol, to a grim, unliveable environment.  As Bristol grows hotter with each passing year, with the expectation that by 2050 life-threatening heatwaves will occur once every two years (not to mention the increasing flood risk to this area), we will need the cooling benefit of large, mature trees yet, tree by tree, they are inexorably removed in order to maximise profit and achieve what many say is an unrealisable aspiration. With the majority of new housing being sold at full market price, these will be as much for the benefit of the estimated 1,900 annual migrants from London as they are for the more affluent citizens of Bristol.

It is especially sad that Goram Homes, the much-lauded development arm of Bristol City Council, continues to ignore our very own key green planning policy, BCS9, and the revised National Planning Policy Framework (the Framework) upon which it is based. BCS9 states that ‘Individual green assets should be retained wherever possible and integrated into new development’.

The Framework is the foundation upon which BCS9 is based:

We had hoped that Goram Homes would have set a good example – especially since the Council has recently published its Ecological Emergency Action Plan and announced that it will “embed nature into all decisions” – and abide by these important principles. What has happened to the Framework’s third, overarching environmental objective? Taking Baltic Wharf Caravan Park as an example, it would have been quite straightforward to design any new housing around existing trees, particularly if the focus was on just building affordable and social housing. Instead, nearly all are going. This, it seems, is ‘Placeshaping’, Bristol-style.

And this intransigence has resulted in damaging national press coverage – though note the lovely photo of the trees growing on the site.

Our objections to the proposals are set out here, but we are not the only ones…

Councillor Mark Wright’s experience

Councillor Mark Wright was the councillor for Hotwells and Harbourside until May 2021 when he stepped down.  Here he presents his experience of the many attempts he made to engage with the planners and Goram Homes at an early stage to try to secure as good an outcome as possible given that the caravan park was doomed to be closed. They came to nothing.

Mark writes:

Sept 2018

Mayor Rees announces that flats will be built on the site.

Dec 2018

I wrote to Cllr Paul Smith (Housing) “There are a number of very nice trees on the caravan park site that residents are already calling for saving (see attached Google 3D image). If done skilfully and at an early enough stage, many of the best trees could be embraced into the development in a way that greatly increases the value of the retail flats. If done too late or not at all, it’s likely that getting planning permission will become a battle over trees, which isn’t what anyone really wants. I think it would be a good demonstration of why Goram is a good thing if it sets the bar high on pre-app planning on things like this – it could really set an example to other developers. I understand that planning policy BCS9 requires the developer (i.e., BCC in this case) to do a tree constraints plan as early as possible – there is no need to wait until the actual plans start to form to do this. Can we get BCC to start this ASAP?” Cllr Smith replied, “I will have a word with officers”, but I got no further response.

I also wrote to the Council’s Arboricultural Officer, Matthew Bennett, asking for a tree assessment report to be done ASAP so that the best trees on the site could be saved and incorporated into the plans. I was interested in getting TPOs put on the best trees, but at that early stage Bennet replied to me: “Our aim through the planning process is to secure the best trees on site and mitigate the loss of those removed through the planning obligations SPD (BTRS). We cannot try and save every tree {…} a tree preservation order would not help the situation because full planning consent overrides a TPO”. That seemed reasonable so I concentrated on trying to get a tree report.

Jan 2019

I contacted officers again for an update but got no info.

Early Feb 2019

Planning Officer Paul Chick told me that no arboricultural tree report would be done until a pre-app was submitted, but no one knew when that would be.

Late Feb 2019

I raised the issue of trees on the site with Cllr Paul Smith and Steve Blake at Goram (Development manager); Cllr Smith said he had raised the issue of trees after my earlier contact, but I heard nothing more.

Jun 2019

I again raised the issue of trees on the site with Steve Blake at Goram and Matthew Bennett but got no response.

July 2019

A tree report was secretly written for the Council, but I wouldn’t see it until December 2020.

Dec 2019

The first concept images of the plans were released to the public. I wrote to Steve, Matthew, and Paul Smith again: “I note with interest the Council’s press release today indicating that a development partner has been selected for this housing site. There is even a picture of the proposed build. I presume this *must* mean that there has been enough preliminary work done to allow a tree constraints report for the site to be drawn up. Please can you assure me that the prime trees currently on the site are being designed into this new plan? A development such as this will be greatly enhanced in value by the intelligent and thoughtful retention of mature trees, and the Council’s reputation as a builder will be greatly enhanced as well, setting a higher bar in the city for other developers to follow…”

I got no responses…

Jan 2020

I wrote to Tim Bluff, a new contact at Goran Homes (taking over from Steve Blake, presumably) I had been given after badgering people. Bluff informed me that a tree report had in fact been done 6 months previously. I had never been told about it, despite asking multiple people for it for 13 months. I was told at this point the document wasn’t public and I couldn’t see it.

Feb 2020

There was a public *showing* of the plans. At this point it was clear that the plans were essentially almost “final” despite there having not been a single public engagement session of any kind, about anything. I declared publicly that I was concerned about both height and loss of trees.

Mar 2020

I discussed with the Bristol Tree Forum doing an informal assessment of the trees, but the Covid lock-down squashed that.

Apr 2020

The pre-app was published privately on the planning portal, but I couldn’t have access.

Early May 2020

The pre-app was made available to me, but not the public. It was clear that all trees on the site would be felled; all that would be saved was some of the boundary hedges. Again, by this point there had still been zero public engagement on any issue, only a showing of the images. The 10-month old Arboricultural report (i.e., July 2019) was still not available to anyone, including the Council’s own Arboricultural officer Matt Bennett, who wanted it too.

Late May 2020

I had a video meeting with Stephen Baker, Development manager at Goram (and Geoff Fox and Glynn Mutton) to discuss the plans. I made it clear I was unhappy with the height, the loss of all trees was a major problem, and the lack of any public input before publishing the plans was a big mistake and contrary to planning requirements on major plans. Steve said the trees were all being lost because the site had to be raised 2m to allow “active frontages” that comply with planning regs. I said that saving trees might be preferable to active frontages inside the site; I asked him who made this critical decision and when, as this was exactly the kind of thing the public should have fed into – at least if the decision had been informed by the public there would be some buy-in. He said he didn’t know and it had all happened before he joined the project. I made clear I was disappointed, but I really didn’t want to end up opposing the plans, and I hoped there would be a reduction in the height.

Oct 2020

Website for the plans went up.

Dec 2020

I finally received a copy of the July 2019 tree report – from the Bristol Tree Forum, not from the Council! It was clear that the decision to fell all trees on site had already been made earlier than July 2019.

Apr 2021

Full Planning app submitted, with no real changes since the pre-application stage. I lodged an objection “with heavy heart”.’

Valuing our urban trees

At last, some good news: city trees have been given the same habitat and biodiversity value as their country cousins.
Or have they?

STOP PRESS

Since writing this blog, we have now responded to Defra’s Small Sites Metric (SSM) Consultation. It develops further our critique of the way that urban tree habitats are being undervalued. Perhaps urban trees are now the poor country cousin? Here it is:

Bristol Tree Forum response to the Small Sites Metric consultation.


Our Original blog

The important contribution that urban trees (native and non-native) make to our cities has finally been recognised by Natural England, with their publication of Biodiversity Metric 3.0 (BM3.0) on 7 July. It states that:

Trees in urban areas can, under the right conditions, provide a large range of habitat opportunities, supporting lichens, bryophytes, invertebrates and birds. Tree planting in urban areas has for over two hundred years also introduced non-native species into towns and cities. In the context of biodiversity, native species are the preferred option. However, non-native tree species can contribute positively to biodiversity richness particularly in relation to providing a seasonal food source for nectar feeders and other invertebrates as well as supporting vertebrates that feed on species that are hosted by non-native trees. Examples are early and late flowering species of Prunus and aphids on varieties of Acer providing food for species higher up the food chain.

Trees in urban areas provide opportunistic sites for biodiversity to colonise and re-colonise, increasing connectivity and contributing to biodiversity critical mass between already established patches or sites. This is especially true where transport corridors are populated with mixed native species.

What’s an urban tree?

The new BM3.0 habitat category, urban tree, includes individual trees, lines of street trees and blocks of trees growing within the urban setting.

BM3.0 Guide – TABLE 7-1: Urban tree definitions

The previous urban tree habitat categories, woodland, orchard and street tree, which appeared in the beta test version of Biodiversity Metric 2.0 (BM2.0) have been discarded.

The urban tree habitat calculation has been set to ‘medium’ distinctiveness and ‘low’ difficulty for both habitat creation and enhancement. Urban trees are categorised into small, medium or large. Their condition may also be assessed as poor, moderate or good.

The problem with BM3.0

The three size bands set out in the table below are useful when creating new habitats or enhancing existing ones (for example, nursery-raised standards ready for planting have a stem diameter of around 30 cm and so are Medium). However, these bands are not useful for assessing the baseline habitat of existing urban trees.

This is the size table used in BM3.0:

BM3.0 Guide – TABLE 7-2: Urban tree size by girth and their area equivalent

(NB: the second column of this table is wrongly labelled. It should read Girth (circumference) at Breast Height, not Diameter.)

This table is based on the methodology adopted for calculating the Root Protection Area (RPA) that must be set aside (protected) during the development of sites where trees are growing or likely to be affected. It is set out in BS:5837 2012 Trees in relation to design, demolition and construction, Recommendations. Its purpose is to make sure that the tree is not damaged during development.

The RPA formula used is simple: RPA radius = 12 x DBH (Stem Diameter is also known as DBH – Diameter at Breast Height). This value is then used to calculate the RPA using the formula DBH = PI * RPAr^2.

Every application to develop land where trees will be affected should produce a BS:5837-compliant survey, called an Arboricultural Impact Assessment (AIA). This will report the stem diameters of all the trees growing on and around the site. The AIA also reports several other tree features including species, height, cardinal point canopy radii, condition, life stage and the BS:5837 category – a measure of the quality of the tree.

However, the BM3.0 table above provides no logical way of establishing whether a given surveyed tree with a stem diameter of, say, 15 cm or 40 cm – halfway between categories – is Small, Medium, or Large.

It would be better if the table gave ranges – say Small up to 10 cm, Medium 10-50 cm and Large 50 cm or more – but this has not been done. Also, doing this would distort the habitat calculation with all Small trees set to their upper range and all Large trees set to their lower range.

Our solution

Why use the table at all? It would be far simpler to calculate a tree’s baseline habitat area just by using the calculated RPA provided in the AIA. It would be better still to use its actual measured canopy area, which will have been reported in the AIA and thus be readily available.

In our view, RPA does not reflect the habitat value of a tree. All it does is use a formulaic approach to solving the problem of finding an acceptable way to protect trees. It bears little relationship to the habitat or biodiversity value of a tree.  It would be far better to calculate a tree’s canopy cover (TCC), the standard method of working out the value of a tree. Every AIA reports the canopy radii of the four cardinal compass points of each tree surveyed. These can be averaged and used to calculate TCC.

The Bristol One City Plan adopted TCC as the measure of tree planting success when it set the target to double TCC by 2046. TCC is a standard measure used by the various i-Tree tools and Forest Research uses it in its UK Ward Canopy Cover Map which used i-Tree Canopy. We used it to calculate the TCC of the city’s wards in our 2018 Bristol Tree Canopy Cover Survey and we are using it to update the new city-wide survey for 2021.

We made these observations when Natural England was consulting on its beta test version, but these seem to have been overlooked. We hope they now take note.

Some further thoughts

The introduction of the three new urban tree poor/moderate/good condition criteria, set out in detail in the BM3.0 Technical Supplement, will require all AIA surveys to include this data. Perhaps BS:5837 should be updated to require this to be recorded in the AIA.

Where tree surveys identify mixed urban tree conditions, the person undertaking the BM3.0 calculation will need to record more than one urban tree baseline habitat to capture this information.

BM2.0, which was only published as a beta test to allow for wider public consultation, is still being used by Bristol’s Local Planning Authority (LPA) for pending applications but needs to be abandoned. Pending applications which require a biodiversity net gain report should be required to recast their calculations using BM3.0 rather than still relying on BM2.0. This is particularly true for the Council’s own, direct applications such as the one pending for the Baltic Wharf Caravan Park.

Our initial analysis shows a significant net gain deficit when BM2.0 is used instead of BM3.0. This is especially true for urban street trees, which are significantly undervalued under BM2.0. Furthermore, the LPA is currently allowing applications which propose a zero net gain outcome, even though the Environment Bill (currently being considered in Parliament) will require a net gain of 10% above the baseline valuation.

Given that the Council has declared climate and ecological emergencies and aims to achieve carbon neutrality by 2030, it is surprising that developers continue to be allowed to present biodiversity net gain proposals that either undervalue biodiversity or offer no net gain whatsoever.

Conclusion

We welcome the publication of BM3.0, but its flaws need to be rectified.

The Council’s declaration of climate and ecological emergencies and its commitment to achieve carbon neutrality by 2030 means that it needs to ensure that the latest, most accurate biodiversity net gain calculations are part of all pending and future planning applications.

As Natural England recognises in its recent blog – Biodiversity Metric 3.0 – a milestone moment for biodiversity net gain:

Publishing Biodiversity Metric 3.0 was a landmark moment for biodiversity net gain, it will become the metric used to calculate and evidence whether a project has achieved the biodiversity net gain requirements set out in the Environment Bill. Biodiversity Net Gain (BNG) is:

an approach to development, and/or land management, that leaves nature in a measurably better state than beforehand‘ …

Biodiversity Metric 3.0 ensures that:

all habitats, from street trees to woodlands, green roofs to grasslands are recorded, scored and valued for their importance for wildlife. At the same time, it provides an evidence-based, transparent, consistent and easy to use way of ensuring that nature is considered within the design of developments and in land management practice, leaving nature in a better place than it was before, benefitting wildlife, people and places.

Consultation on proposed changes to NPPF and the National Model Design Code

Individual planning decisions, development designs and local and national plans for development all impact local communities. We urge the Ministry of Housing Communities and Local Government to consider our views on the design codes and to continue to engage communities and groups such as ours in local planning decisions.

Here are our detailed responses to the consultation.


The changes proposed in Chapter 2 – Achieving sustainable development

Paragraph 7 – We agree with the introduction of the 17 Global Goals for Sustainable Development. These have been adopted by Bristol as part of its One City Plan so their adoption in the NPPF will be essential for ensuring that the city’s core planning policies are aligned with its wider goals.

Paragraph 8 states:

‘Achieving sustainable development means that the planning system has three overarching objectives, which are interdependent and need to be pursued in mutually supportive ways (so that opportunities can be taken to secure net gains across each of the different objectives).’

We would also like it to be made as clear as possible that these three overarching objectives are indeed ‘interdependent and need to be pursued in mutually supportive’ ways so that no one objective takes precedence over the others, as has been our experience with a number of recent planning decisions made in Bristol.

We propose that the paragraph amended to read: ‘Achieving sustainable development means that the planning system has three overarching objectives, which are interdependent and need to be pursued in mutually supportive ways so that no one objective is treated as having precedence over the others (so that opportunities can be taken to secure net gains across each of the different objectives)’

Paragraph 11 a) – We also endorse the proposed change that ‘all plans should promote a sustainable pattern of development that seeks to: meet the development needs of their area; align growth and infrastructure; improve the environment; mitigate climate change (including by making effective use of land in urban areas) and adapt to its effects’. Trees are an important component of this, particularly where green space is limited.


The changes proposed in Chapter 3 – Plan making

Paragraph 22 – We agree that ‘where larger-scale development such as new settlements form part of the strategy for the area, policies should be set within a vision that looks further ahead (at least 30 years), to take into account the likely timescale for delivery’. Too often, trees that were planted where a site was last developed (often only a few years before) are sacrificed to the short-term goals of the new proposal. Setting longer-term goals can help prevent this.


Proposed changes to Chapter 4 – Decision making

Paragraph 53 – Of the two options offered[1], we prefer the second – ‘where they relate to change of use to residential, be limited to situations where this is necessary in order to protect an interest of national significance’. In our view, the phrase ‘wholly unacceptable adverse impacts is open to too wide an interpretation which may not be rooted in wider national goals.

We agree that that Article 4 directions should be restricted to the smallest geographical area possible. 


The changes proposed in Chapter 8 – Promoting healthy and safe communities

We welcome many of the additions and changes proposed, including the recognition that a well-connected network of high-quality, open, green and wooded spaces is important for both our mental and physical health.

Paragraph 97 – We believe that access to a network of high-quality open spaces and opportunities for sport and physical activity ‘should always deliver wider benefits for nature and efforts to address climate change.


The changes proposed in Chapter 12 – Achieving well-designed places

Paragraph 128 – We agree that all guides and codes should be based on effective community engagement and reflect local aspirations for the development of their area.

Meaningful community engagement at all stages of the planning process is essential if the changes proposed are to succeed. Too often, communities are not asked to engage with planning proposals until they are published and the formal approval process has started. By this time most of the key decisions have been agreed between the developer and the planner and it is too late for any meaningful consultation with the wider community.

Paragraph 130 – We welcome the introduction of this new paragraph:

‘Trees make an important contribution to the character and quality of urban environments, and can also help mitigate and adapt to climate change. Planning policies and decisions should ensure that new streets are tree-lined, that opportunities are taken to incorporate trees elsewhere in developments (such as community orchards), that appropriate measures are in place to secure the long-term maintenance of newly-planted trees, and that existing trees are retained wherever possible. Applicants and local planning authorities should work with local highways officers and tree officers to ensure that the right trees are planted in the right places, and solutions are found that are compatible with highways standards and the needs of different users.’

We must learn to value our urban trees and woods growing in Bristol (and in other cities), so we were pleased to see this addition with the ambition to ensure that all new streets are treelined, but city-wide planning involving existing streets and road networks must also make space for new tree planting in the design process as well as ensuring that existing trees are retained.

Generally, planning requirements must be tightened to ensure that existing trees are retained. Only in exceptional cases where there are clear, justifiable and compelling reasons to do so should trees be removed. In all cases the cascading principles of the Mitigation Hierarchy must be applied and, where there is no option but to remove a tree, the loss of habitat and biodiversity that the tree provided must be compensated for by an adequate tree replacement calculation such as that used in the Biodiversity Metric calculation.

We agree that ‘development that is not well designed should be refused (paragraph 133). Designs that fail to make provision for preserving existing trees and providing new trees are not, in our view, well-designed and so should be refused.


The changes proposed in Chapter 13 – Protecting Green belt Land

New Paragraph 149 – We propose the deletion of this text, which is too general and open to interpretation. Certain other forms of development are also ‘not inappropriate in the Green Belt provided it preserves its openness and does not conflict with the purposes of including land within it’.

In Bristol there are just over 596 hectares of Green Belt left within the metropolitan boundary, mostly confined to the few remaining green margins of the city. The last draft of the Local Plan proposed the removal of some 50 hectares for development. Already parts of the Green Belt are disappearing without any hint that this ‘preserves its openness and does not conflict with the purposes of including land within it’. Little by little, development by development, Green Belt land is being lost.


The changes proposed in Chapter 14 – Meeting the challenge of climate change, flooding and coastal change

Paragraph 160 c) – Tree preservation and the planting of new trees are key elements of ‘using opportunities provided by new development and improvements in green and other infrastructure to reduce the causes and impacts of flooding, (making as much use as possible of natural flood management techniques as part of an integrated approach to flood risk management)’ We would like to see text added that states this.


The changes proposed in Chapter 15 – Conserving and enhancing the natural environment

Paragraph 179 d) – This states that ‘development whose primary objective is to conserve or enhance biodiversity should be supported; while opportunities to improve biodiversity in and around other developments should be pursued as an integral part of their design, especially where this can secure measurable net gains for biodiversity and enhance public access to nature’.

It is essential that core planning policies mandate a standard metric for measuring baseline and created and enhanced habitat biodiversity proposals. Developers must be obliged to provide a Net Gain calculation when submitting their proposals. The latest version of the Biodiversity Metric Is designed for this purpose and should be mandated for all new planning proposals. All planning permissions should require the delivery of Biodiversity Net Gain plans of at least 10%.


We would be grateful for your views on the National Model Design Code, in terms of a) the content of the guidance b) the application and use of the guidance c) the approach to community engagement

The design codes must deliver three key things to ensure that new developments always provide access to high-quality, local green space and to trees, with all the benefits these provide for communities.


  • Protect and integrate existing trees  

New developments must incorporate and protect existing trees from the outset. There must be a presumption that the design will accommodate the existing trees growing on and around the site – especially those growing around the edges of sites. Designs should consider the long-term health of trees in and adjacent to new developments and aim to promote this. This will include providing adequate buffers for ancient, veteran and self-seeded trees and woods.

  • Increase canopy cover  

New developments must have a target of providing a combined minimum of 30% canopy cover on and off site. This should be made up of a mix of tree-lined streets, community woodlands, Tiny Forests, parks and gardens. Where tree provision will be made off site, the cost of providing, planting and caring for the trees on a long-term basis should be funded by the developer and incorporated into tree-specific S106 agreements (T&CPA 1990). Where possible, trees should be native and sourced and grown in the UK. Trees that will become large and are long-lived should be selected where possible.

  • Ensure trees thrive for the long term  
<p value="<amp-fit-text layout="fixed-height" min-font-size="6" max-font-size="72" height="80">Local authorities must be properly resourced so that they can implement design codes and other areas of planning policy. Resource needs to be available for decisions to be enforced and to ensure long-term management of trees by tree officers.Local authorities must be properly resourced so that they can implement design codes and other areas of planning policy. Resource needs to be available for decisions to be enforced and to ensure long-term management of trees by tree officers.
  • Community engagement

As we have already noted, meaningful community engagement is essential if communities are going to consider that they ‘own’ planning decisions rather than having them imposed on them.

We have published a paper on the issue as it relates to consultation on the management of trees which we commend to you: ‘Community engagement in urban tree management decisions: the Bristol case study’.

3 March 2021

You can download a copy of our submission here.

Here are copies of the draft National Planning Policy Framework and National Model Design Code.

The consultation closes on 27 March 2021 and can be accessed here – National Planning Policy Framework and National Model Design Code: Consultation proposals.


[1]  ‘a) where they relate to change of use to residential, be limited to situations where this is essential to avoid wholly unacceptable adverse impactsorb) where they relate to change of use to residential, be limited to situations where this is necessary in order to protect an interest of national significance’.

Trees valued at over £4.6m are under threat at Bonnington Walk, Lockleaze

Whatever the merits of this application of achieving its primary goal to provide much needed housing may be, it should not be permitted to proceed unless and until it has properly addressed how it will replace and build upon the Green Infrastructure (including trees) that will inevitably be lost if this application proceeds as presently formulated.

Summary of our submission

We object to this application for the following reasons.

Bristol City Council has:

Declared climate and environmental emergencies.

Committed to becoming carbon neutral by 2030.

Committed to doubling tree canopy cover by 2046.

As currently formulated, these plans to build new houses can only set back the work needed to resolve these emergencies and achieve these commitments.

  1. The need to build housing to meet sustainable economic or social development objectives should not be allowed to take precedence over ensuring that the development is also both environmentally sustainable and meets Net Gain objectives.
  2. Whatever the merits of this application of achieving its primary goal to provide much needed housing may be, it should not be permitted to proceed unless and until it has properly addressed how it will replace and build upon the Green Infrastructure (including trees) that will inevitably be lost if this application proceeds as presently formulated.
  3. The existing trees have a significant asset value which should not lightly be ignored. Using CAVAT, we have valued them at £4,674,918.
  4. Under the Mitigation Hierarchy, trees should not be removed unless there is no realistic alternative. One alternative would be to build around the trees rather than remove them.
  5. BCS9 of the Core Strategy also states that “Individual green assets should be retained wherever possible and integrated into new development”. Clear felling nearly all the trees to the east of the cycle/footpath should not, as it so often is, be the default option.
  6. Trees should not be removed merely because they are diseased or self-sown, or because they are small or not perfect specimens of their species.
  7. The removal of existing trees inevitably means that the eco-services they provided will not be replaced for decades, if at all.
  8. The adverse knock-on environmental impact on biodiversity of removing existing trees far outweighs any short-term benefits achieved by replacing them.

Our submission

The planning background

The National Planning Policy Framework

The National Planning Policy Framework (NPPF) seeks to ensure that new development is sustainable. It stresses the importance of Green Infrastructure as one of three overarching, interdependent objectives – economic, social, and environmental. This means that the presumption in favour of sustainable environmental development is just as important as any in respect of economic or social development objectives.

Trees are an integral part of this because of the importance of trees in relation to the management of air, soil and water quality along with other associated ecosystem services, climate change adaptions and beneficial health effects. The NPPF also seeks to achieve the protection and enhancement of landscapes and achieve Net Gain in biodiversity.

The Natural England Joint Publication JP029 – Biodiversity Metric 2.0 (BDM2) provides a way of measuring and accounting for biodiversity losses and gains resulting from development or land management change. It defines Net Gain as an:

“approach to development that aims to leave the natural environment in a measurably better state than beforehand. This means protecting existing habitats and ensuring that lost or degraded environmental features are compensated for by restoring or creating environmental features that are of greater value to wildlife and people. It does not change the fact that losses should be avoided where possible, a key part of adhering to a core environmental planning principle called the mitigation hierarchy.”

The Mitigation Hierarchy

Avoid – Where possible habitat damage should be avoided.

Minimise – Where possible habitat damage and loss should be minimised.

Remediate – Where possible any damage or lost habitat should be restored.

Compensate – As a last resort, damaged or lost habitat should be compensated for.

This is a cascading decision process – only if the preceding choice is unavailable is the next considered.

Local Planning Authorities (LPA) in the UK have a statutory duty to consider both the protection and planting of trees when considering planning applications. The potential impact of development on all trees is therefore a material consideration. In particular, BCS9 of the Core Strategy states that “Individual green assets should be retained wherever possible and integrated into new development”.

We have summarised Bristol’s planning policies as they relate to trees here – Planning obligations in relation to trees in Bristol.

Summary of the proposal in relation to trees

This site covers just over six hectares. The Lockleaze Allotments (a 0.8 hectare Statutory Allotment[1]) is located to the south east of the widest part of the site. It appears to be disused. Most of the substantial trees growing on the site are growing in or around this allotment or to the north of it. We have calculated that, taken together, they cover at least 1.3 hectares of the site – a tree canopy cover (TCC) of around 20% which is well above the estimated TCC for Bristol as a whole which is just under 12%.

All our calculations, summarised below, can be examined in this linked spreadsheet.

The Arboricultural Impact Assessment Report (the AIS) dated June 2020 (based on a survey done on the 19th and 20th of September 2019) identified a combined total of 58 individual trees and 40 tree group features. The number of trees in each group is not given, so it is not possible to say how many trees in total are growing on the site.

Of all the trees growing on site 24 individual and at least 251 group trees are identified for removal. The trees growing in Groups G69 and G74 are all to be removed, but the number of trees in each group is not identified so we have not been able to include or count these in our calculations.

The only reason for given for felling these two groups is because they show evidence of Ash Dieback (Hymenoscyphus fraxineus). As the AIS recognises, the mere presence of Ash Dieback is not a sufficient reason for the removal of a tree. We oppose the removal of these tree unless it can be shown that they there is a better reason for their removal.

The CAVAT calculation

Using CAVAT we have calculated that those identified trees which have a measured stem Diameter (DBH) are worth £4,674,918.  As the AIS fails to give the upper life expectancy ranges[2] of the majority of trees, we have assumed that all those trees given a 10+ or 20+ years life expectancy will survive between 40 and 80 years. This attracts a 5% discount on the base valuation. We have applied a CTI factor for Bristol of 150[3]. All the other factors are set to their default values.

The BTRS calculation

These two tree groups and five individual trees are categorised as Category ‘U’ trees under BS5837:2012 Trees in relation to design demolition and construction, and so have not been taken into account for the purpose of the Bristol Tree Replacement Standard (BTRS) calculation. A further 10 trees are also excluded from the BTRS calculation because their stem diameters are under 15 cm. We advocate that all trees identified for removal should be replaced no matter what their size.

Notwithstanding this and based on the current guidance, we have calculated the BTRS value at 455 trees as per the AIS calculation.

Net Gain calculation

No Net Gain calculation has been undertaken using BDM2 in support of this application.

We have undertaken our own BDM2 calculation in respect of just the trees surveyed in support of this application. A full calculation needs to be undertaken in respect of the whole of the site. This will inform any future decision about achieving Net Gain if this development is to be allowed to proceed.

Using BDM2, we have calculated that the combined tree canopy cover[4] of just the known, measured trees is 1.21 hectares. We have set the A-1 Site Habitat Baseline Habitat Type to Urban – Street Tree in the calculation. This assumes, amongst other things, that any replacement trees will reach maturity in 27 years and so uses a multiplier of 0.3822 to reflect this.

This gives Base Habitat Units of 5.864 and a Base Replacement value of 3.17 hectares. If we add an arbitrary Net Gain value of 10%[5], then the Base Habitat Units increases to 6.451 and the Base Replacement value to 3.49 hectares. Assuming that a 27-year-old tree has a canopy of .00403 hectares, then 866 replacement trees are needed to replace what has been removed and to achieve Net Gain.

Loss of the ecosystem services of trees

We invite you to consider the decades-long damage that felling just one tree (let alone over 277 trees) will cause by inputting the DBH of any tree identified for removal into our Tree CO2 Calculator.

As you will see, when an equivalent tree is replaced on a one-for-one basis, the lost CO2e is never recovered. Even when the largest tree (with a DBH of 100 cm) is replaced with eight trees in accordance with BTRS, it will still take some 40 years to recover the 10.4 tonnes of lost CO2e. And this is just one of the eco-services that trees provide us!

Impact on wildlife from tree loss

We endorse the following passages from the Bonnington Walk Breeding Bird Survey Report which observes at 5.2 Habitat Loss:

The Proposed Development will include the loss of scrub, trees and buildings which provide habitat for breeding birds. The extent of habitat loss is likely to include all the scrub and trees in the centre of the Site with some edge habitat along the boundaries retained…The loss of this habitat will have an impact on any birds using it for foraging or breeding at the time. The Site is located within an urban landscape with limited natural habitats. Alternative habitats are not readily available adjacent to the Site, though alternative habitat is available in the wider landscape including Stoke Park Estate and connected habitats further east. Habitat loss on Site will have an impact at a Local level by reducing breeding bird habitat in the local area…

and at 6.2.1 Habitat Loss:

Where possible, habitat loss should be avoided, and natural habitats retained. Scrub and trees are of most value to breeding birds at this Site. When natural habitats are retained these should be protected during construction to prevent damage including root compaction and knocking off or damaging over hanging limbs.

This is just one example of the likely adverse impact on wildlife resulting from these tree removal plans. There is evidence of a diverse range of both flora and fauna that likewise will also be adversely affected by the loss of these trees.

The Bristol Tree ForumJuly 2020

You can find more detail about the application here:

20/02523/FB – Land on south side of Bonnington Walk, Bristol


[1] Owned by BCC under its asset number 8397.

[2] CAVAT uses six age ranges to set the discount factor.

[3] Bristol has a population of 459,300 and a land area (as opposed to the Administrative area which covers large parts of the River Avon and coastal margins) of 10,970 hectares. Using this gives a population per hectare of 41.9 (459,300/10,970) and so a CTI Index value of 150.

[4] Under BDM2 each tree’s Root Protection Area (RPA) is calculated at 12 times its stem diameter. RPA is roughly equivalent to a tree’s canopy.

[5] The choice is arbitrary chosen only for the sake of illustration. We are not advocating a Net Gain of 10%, though the concept of Net Gain implies an improvement on the base values.

Bristol City Development – Where did all the Green go?

The Climate and Ecological Emergency

In 2018, with much fanfare, Bristol City Council (BCC) declared a Climate Emergency, the first UK city to do so, preceding the UK government by over a year. This has been followed up by the declaration of an Ecological Emergency, and a raft of sustainability aspirations detailed in the Bristol One City plan including doubling the tree canopy by 2046, doubling wildlife abundance by 2050, and City-wide carbon neutrality by 2030.

So why is it that so much of our informal green spaces are still being lost, and so many of our trees continue to be felled?

Is the BCC Development Office blocking Climate and Environmental Action?

A clue to this came out of a recent planning application to build a 4-storey block of flats in St Paul’s, in a street with one of the highest illegal levels of pollution in Bristol, above recommended noise levels, in a known high flood risk area and on land thought to be contaminated.  It was shown that the planned development would increase pollution and noise levels. Furthermore, in an area with one of the lowest tree density in Bristol, five mature maple trees were to be felled, removing the last mitigation for noise, pollution and flooding in the street. The trees are on the very edge of the development site and could therefore have been retained, readily complying with BCS9 which states “Individual green assets should be retained wherever possible and integrated into new development”.

Bristol’s Planning policies are contained in two main documents:

These are supplemented by the Planning Obligations Supplementary Planning Document. All were variously adopted and implemented by the Council between 2011 and 2014.

Despite contravening core strategy planning policies on green infrastructure (BCS9, DM15), pollution (BCS23, DM33), climate change (BCS13), flood risk (BCS16), noise (BCS23, DM35) and health (DM14), the Development Office did everything in its power to promote and advocate this development.

The reasons for this became clearer when officers were asked during the Planning process specifically why they supported a development which breached so many core policies aimed at protecting the health of citizens, the environment and the City’s crucial green infrastructure.

The Head of Development Management responded, “With regard to this application, the policy aims of the Core Strategy could be seen as the delivery of housing (BCS5), including affordable housing (BCS17)”. Further, “Loss of green infrastructure will only be acceptable where it is…… necessary, on balance, to achieve the policy aims of the Core Strategy”.

The statement effectively says that, whilst the need for new and affordable houses remains, BCS5 and BCS17 can override other policies including those mentioned above. Thus, green infrastructure that could have been retained is ignored, pollution and noise levels above legal limits are permitted, and the worsening health of residents would be tolerated. This position seems to be contrary to that previously held, with development under BCS5 and BCS17 needing to be also in compliance with the other core policies. As there will always be a need for new homes and affordable homes, the concern is that all other policies can be set aside indefinitely.

We would suggest that BCC Development Office interpretation is in contravention of the National Planning Policy Framework (NPPF) which states that: “the purpose of the planning system is to contribute to the achievement of sustainable development (remember that phrase), including “an environmental objective” – to contribute to protecting and enhancing our natural environment, including helping to improve biodiversity, mitigating and adapting to climate change and moving to a low carbon economy”.

So how has the BCC Development Office responded to BCC’s Climate and Ecological declarations?

The Development Office was also asked how implementation of planning policies had been influenced by the Climate and Ecological Emergencies. Their response was:

“Whilst Climate and Ecological Emergencies have been declared by the Council, the Bristol Local Plan has not been fully reviewed in the light of these and the policies referred to remain unchanged. Changes to Local Plan policies would have to balance the objectives of the respective declarations with the requirement to deliver sustainable development for the city”.   

By “balance”, it seems they may effectively mean “ignore”. Clearly their definition of sustainable development is somewhat different to that defined in the NPPF, with no intrinsic “environmental objective”, and, as one Councillor on the Committee remarked, the development will “lead to poorer people having shorter lifespans”. Unpacking their response still further, the implication is that there are currently no core policies in place to implement the Climate and Ecological emergencies. As described above, this is not true. Were BCS9, DM15, BCS23, DM33, BCS13, BCS16, DM35 and DM14 to be applied as intended in the NPPF, there would be sufficient policy support at least for the principles of the two emergency declarations.

Is this being led by bureaucratic or political decision making?

It is not clear why the Development Office has taken this position, but there are two possibilities that should be of concern:

  • The Development Office is acting contrary to the aspiration of the City’s political leaders.
  • Senior Council politicians who have made much political capital from the highly praised environmental declarations, have at the same time permitted, or perhaps even encouraged, Council Officers to disregard existing planning policies that would otherwise enable implementation of these declarations.

Thus, selective policy compliance allows development of second-rate housing in a race for quantity over quality.

It seems that Bristol City Council are choosing to emphasise some core strategic policies aimed at hastening house building, whilst demoting other core strategic policies aimed at protecting public health, green infrastructure, air quality and the environment. This is a recipe for slum development, and we deserve to know whether these decisions are being taken at a political or bureaucratic level.

Professor John Tarlton.

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