Farewell to the Meadows

A small grove massacred to the last ash,
An oak with heart-rot, give away the show:
This great society is going to smash;
They cannot fool us with how fast they go,
How much they cost each other and the gods.
A culture is no better than its woods.

W.H. Auden from ‘Bucolics, II: Woods’

Nearly six weeks ago, on 17 April, our hopes of preserving our beloved Brislington Meadows were dashed. Homes England has been allowed to continue with its plans to use the land for housing. The almost universal cry of ‘No!’ from across the city has fallen on deaf ears; Homes England will carry on regardless.

But we haven’t given up. We have all – The Bristol Tree Forum, Greater Brislington Together and Save Brislington Meadows Group – been searching high and low to find a way to stop this, even at the eleventh hour. And we’ve succeeded! We’ve found serious omissions in the planning inspector’s decision which, we believe, give us grounds to have it overturned.

Here’s a summary of the reasons why we think the decision should be set aside. They are a bit technical, but they are important:

  1. The Inspector’s Decision has entirely missed the fact that part of the site – part of the proposed vehicle access at the north-west corner to Broomhill Road, with a strip of housing development there (the only viable point of access onto the development site) – is designated in the adopted Site Allocations and Development Management Policies (SADM) as ‘Important Open Space: Belroyal Avenue, Brislington’.
  2. SADM policy DM17 states: ‘Development on part, or all, of an Important Open Space as designated on the Policies Map will not be permitted unless the development is ancillary to the open space use.’  The failure to have regard to this clear conflict with policy was a breach of s.38(6) and s.70 of the Planning and Compulsory Purchase Act 2004. It’s notable that this part of the site is outside of the Site Allocation, discussed below, which the Inspector placed so much weight on.
  3. What’s more, this same part of the development was confirmed by the Council as a public open space called Belroyal Avenue Open Space in its 2008 Bristol Parks and Green Space Strategy. Because of this and its historic use for recreation, the site is protected by a statutory trust under s.10 of the Open Spaces Act 1906.  However, when this land was sold to Homes England in March 2020, the Council failed to meet the requirements of s.123(1) and (2A) of the Local Government 1972. As a result, the site remains subject to the statutory trust, held for the enjoyment of the public, and may not be developed. The principle of the statutory trust was recently confirmed by the Supreme Court in the case of Day v. Shropshire. Even though this case was not brought before the planning inspector (it was published only three days before our three-week planning appeal ended), the legal principle at the heart of it was a material consideration that should have been taken into account in the Inspector’s 17 April decision. This is especially so, given the earlier 1 November 2016 Cabinet decision (item 12) to ignore the 2012 decision of the Greater Brislington Partnership not to declare this land surplus to their Green Space requirements and decide that the land should be sold anyway. Site ‘1’ on map N5954e  – which was available when the Cabinet met in November 2016 – clearly shows the Belroyal Avenue Open Space as owned by the Council and subject to its 2008 Bristol Parks and Green Space Strategy designation.
  4. The Brislington Meadows Site Allocation policy, BSA1201 (at page 154), states that ‘the development should retain or incorporate important trees and hedgerows within the development which will be identified by a tree survey.’ The Inspector identified a number of ‘relatively important trees for the purposes of BSA1201’ which would be lost. To allow this must be a breach of the BSA1202 requirement. Despite this, they then found compliance with the policy. This is irrational, as is the fact that they judged that ‘broadly speaking, the most important hedgerows would see the most retention’. This must mean that some of the other most important hedgerows will be lost. This is also in conflict with BSA1201. 
  5. Compliance with BSA1201 is also used to reduce significantly the weight accorded to the breach of DM17 in respect of the requirement to integrate important existing trees. This gives another ground of challenge in relation to the Inspector misinterpreting the criterion in BSA1201 and/or irrationally failing to acknowledge that the loss of important trees and hedgerows constitutes a breach of BSA1201, being compounded by a consequential reduction in weight accorded to the conflict with DM17.

For all these reasons, we’ve a strong case to make to overturn the inspector’s decision. Time is running out, though – we only have until this coming Friday, 26 May, to issue proceedings. It is tight, but we could do it. But we’ll need to find at least £50,000 to bring and argue our case.

No doubt Homes England would be determined to fight us all the way and, whilst they seem to have access to almost limitless public funds and can afford the most expensive lawyers, we don’t. We’re just a group of local volunteers doing the best we can to save this precious green space. We don’t have much money – certainly not £50,000! Any money we can raise will depend on the generosity of the public. This is a big ask, especially as times are hard and money is tight. Also, should we lose (and we could), Homes England will want their costs paid as well. This is just too much of a risk.

We’ve written to the Council asking if they plan to challenge the decision and have said why we think they have a case. Sadly, we’ve had no answer. We suspect they’ll be reluctant to do so and expose themselves, yet again, to criticism for their mistakes and misjudgements. This is perhaps especially true given that, as well as losing the appeal, the Inspector has also ordered them (actually, us tax payers) to pay a large part of Homes England’s appeal costs.

Here is a copy of this article.

Developing a Tree Strategy for Bristol

Bristol City Council is currently writing a tree strategy for Bristol. This is welcome news, as we have been calling for such a strategy to be developed for more than a decade.

For example, in 2020 we wrote a Manifesto for Protecting Bristol’s Urban Forest.

A tree strategy should be an evolving process rather than a document which may quickly become out of date. This is particularly true in our rapidly changing world – environmentally, climatically and politically.  To provide an effective response to the challenges these present, a group of representatives from both civic and professional groups (along the lines of the Bristol Advisory Committee on Climate Change (BACCC), should be established to help coordinate further research and make recommendations to Bristol City Council and other stakeholders as the situation changes.

We also recommend that the development of a tree strategy should take full advantage of exemplars from other local authorities[1]. We should have the ambition to make Bristol’s tree strategy the best.

Here follow 18 key points that we would expect to see included in a strategy.

  1. Buy in from all the stakeholders involved. Many council departments (as well as Parks, there is Highways, Education and Planning) have a role to play in the management of Bristol’s trees. We need to see evidence that all such departments are fully involved in the development of the strategy. In particular, with the current review of the Local Plan, it is essential that Planning is fully engaged with the strategy, and that the two documents are consistent and properly cross-referenced. The tree strategy needs to be incorporated into the new Local Plan. In addition, other important landowners (such as the universities, utilities providers, housing associations, schools and hospitals) have a role to play in contributing their expertise to the strategy and implementing its goals. As well as the Bristol Tree Forum, many community groups have an interest in tree planting in Bristol and should be involved and consulted.
  2. When council trees are removed, they must be replaced. At present there are more than 800 street tree stumps and empty tree pits around the city – sites where trees once grew. A plan to plant all these missing trees within five years needs to be included. In the future, when any council trees are damaged or felled, they should be replaced within the next planting season.
  3. There needs to be community engagement in tree management decisions both at the level of individual trees and in strategic decisions. In recent years we have seen a rise in community led campaigns to protect trees, such as the Ashley Down Oak, the M32 maples and Baltic Wharf, and this is indicative of a disconnect between the Council and the communities it serves. When the balance of the Environment Act 2021 takes effect later this year, Councils will be obliged to consult when street trees are being considered for removal[2]. This is too narrow and should be extended to include where any public tree is being considered for removal. Therefore, part of the strategy should be promoting community engagement, providing mechanisms for engagement and then taking account of the concerns of the community and tree campaigners alike.
  4. There should be one person responsible for trees within Bristol City Council. At present we have tree planning officers, tree maintenance officers and tree planting officers with no single individual or office accountable overall, often resulting in a lack of appropriate action or people working at cross-purpose. It is also concerning that Highways are able to remove street trees without any consultation.
  5. There needs to be a plan to address the massive inequality in tree cover in Bristol, which often mirrors social and financial deprivation in the City. For instance, additional protections could be given to trees, and tree planting prioritised, especially in deprived areas such as the City Centre, Harbourside and St Pauls.
  6. When developers remove trees, the replacements required should be planted by BCC. Too often developers have shown themselves incompetent or unconcerned when planting trees, so the trees fail or are never planted. In the case of Metrobus, there has been a more than 100% failure rate of trees in some places (trees have been replaced multiple times). We have an excellent tree planting team in Bristol and we should benefit from requiring them to organise and implement the planting required. The cost should be funded by the developer.
  7. Retaining existing trees must be a major part of the strategy. A tree strategy cannot be just about planting new trees, the benefits of which will not be realised for decades, but crucially about retaining and protecting existing trees and the benefits they are already providing. As such, the strategy must address the threats to existing trees. Planning is crucial in this so we would expect major engagement with Development officers to address the current and future problems.
  8. Planning Enforcement must address the illegal removal of or damage to trees. At the moment there are no consequences following the unauthorised damage or destruction of trees. This must change. Other neighbouring local authorities manage to do this but not Bristol. A strategy must include a review of the reasons for the existing lack of effective enforcement and make recommendations as to how this can be rectified.
  9. Developments should be built around existing trees as is already required[3]. Other local authorities do this but not Bristol. This will require a change of culture in the planning department so that pre-application discussions with developers make it clear that this will be required.
  10. The sites for the replacement trees must be agreed before Planning Applications are approved. This is required by planning policy (BCS9 and DM17), but currently developers are being allowed to, instead, pay a “fee” into Section 106, and frequently the replacement trees are never planted. Trees form an important part of our urban habitat. The calculation of tree replacements required to compensate for their loss must be aligned with the Biodiversity Metric as adopted under the Environment Act 2021.
  11. Spend the £ 900K+ reserved for tree planting. Connected with the above point, a strategy needs to include a mechanism for spending the existing £900K+ of unspent tree planting Section 106 money within the next three years.
  12. A strategy to increase Bristol’s tree canopy cover (or at the minimum, maintain existing canopy cover) needs to have a route to implementation This must include addressing the loss of street tree canopy cover by being bolder in selecting new tree planting sites and planting large-form trees wherever possible. Trees such as rowans and flowering cherries are short-lived and will never provide much canopy or become robust enough to survive our challenging urban environment in the long-term.
  13. Canopy Cover needs to be measured with an agreed methodology with confidence limits (levels of doubt in the estimate) made clear. In the first instance, we need to establish the baseline year and percentage tree cover from which progress will be measured. Only then will it be possible to show whether a trend has been determined. Two measurements using different methodologies should not be used to claim an increase in canopy cover. The metric should take account of trees lost so that the figure reflects the true increase, or loss.
  14. Include trees within road changes. There needs to be proper engagement with Highways at early stages of the design process for road changes to look at retaining the maximum number of existing trees and including innovative planting opportunities for new large-form trees, such as pavement build-outs.
  15. For new developments, trees should be properly considered at the pre-application stage, with appropriate consultation with stakeholder groups. Too often, the mitigation hierarchy requiring the removal of trees to be a last resort is disregarded, so that it is only after the design has been finalised that the existing trees are considered and removed where they conflict with the design scheme.
  16. Biodiversity Net Gain (BNG) calculations need to be checked by the Local Planning Authority and biodiversity loss must not be monetised as BTRS has been. BNG, if properly implemented, makes sure that biodiversity on development sites is properly measured and will provide a net gain (soon to be least 10%) is factored in. However, at present, developers’ calculations are not being checked. When we have provided properly evidenced calculations, these have been dismissed by the LPA as mere differences of opinion. You cannot have differences of opinion on facts. The LPA must require that BNG calculations are presented in a way that can be checked by anyone interested and actually do the checking. In addition, ensuring BNG must require that the development site does not lose its biodiversity. If this is not possible, then its immediate local environment must be used to offset any onsite losses. Onsite losses must not be compensated for in some faraway place completely removed from Bristol.
  17.  Planning Applications involving trees must mention this fact in the title. Too often, applications that involve the loss of important trees (or plans to avoid the planting of new trees[4]) do not even mention this fact in the title. This means that it is extremely difficult for community organisations to engage.
  18. Once a planning application has been issued, no removal of trees. A moratorium should be placed on any tree felling pending the outcome of the planning application. This includes applications to demolish buildings which should exclude tree or other habitat removal.

A copy of this blog is available here.

02 May 2023


[1] See for example the Wycombe Council Canopy Cover Doc https://buckinghamshire-gov-uk.s3.amazonaws.com/documents/Canopy-Cover-SPD_3qAkk4z.pdf

[2] https://www.legislation.gov.uk/ukpga/2021/30/part/6/crossheading/tree-felling-and-planting/enacted

[3] Bristol Core Strategy, policy BCS9 states that, “Individual green assets should be retained wherever possible and integrated into new Developments.”

[4] See the Avon Crescent Application pp136 – 155 https://democracy.bristol.gov.uk/documents/g10675/Public%20reports%20pack%2010th-May-2023%2014.00%20Development%20Control%20B%20Committee.pdf?T=10

Our proposal for a new Bristol Tree Replacement Standard using Biodiversity Metric 4.0

The latest version of the Biodiversity Metric (BNG 4.0), just published by Natural England, is likely to become mandatory when the balance of the Environment Act 2021 comes into force later this year. We have revisited our June 2022 proposals and reviewed our calculations. Here is the revised version.

The Bristol Tree Replacement Standard (BTRS), adopted a decade ago, provides a mechanism for calculating the number of replacements for any trees that are removed for developments. It was ground-breaking in its time as it, typically, required more than 1:1 replacement of trees lost to development.

The presumption when considering any development involving established trees should always be that trees will be retained. The application of BTRS should only ever be a last resort. It should not be the default choice which it seems to have become.

The starting point for any decision on whether to remove trees (or any other green asset for that matter) is the Mitigation Hierarchy. Paragraph 180 a) of the National Planning Policy Framework sets it out as follows:

If significant harm to biodiversity resulting from a development cannot be avoided (through locating on an alternative site with less harmful impacts), adequately mitigated, or, as a last resort, compensated for, then planning permission should be refused.[1]

BTRS is and should always be ‘a last resort’. This is reflected in the Bristol Core Strategy, policy BCS9 adopts this approach and states that:

Individual green assets should be retained wherever possible and integrated into new developments.[2]

However, with the development of a new Local Plan for Bristol, we believe that the time has come for BTRS to be revised to reflect our changing understanding of the vital importance of urban trees to Bristol in the years since the final part (SADMP) of the Local Plan was adopted in 2014.

In addition, Bristol has adopted Climate and Ecological Emergency Declarations so a new BTRS will be an important part of implementing these declarations. Nationally, the Environment Act 2021 (EA 2021) will come force later this year. This will require nearly all developments to achieve a Biodiversity Net Gain (BNG) of at least 10%. Our proposal provides a mechanism for complying with this new requirement and so aligns BTRS with the BNG provisions of the EA 2021.

Background

Under current policy – BCS9 and DM17[3] – trees lost to development must be replaced using this table:

Table 1 The Current DM17/BTRS replacement tree table.

However, when the balance of EA 2021 takes effect, the current version of BTRS will not, in most cases, be sufficient to achieve the 10% BNG minimum that will be required for nearly all developments. A new section 90A will be added to the Town and Country Planning Act 1990 and  set out the level of BNG required (see Schedule 14 of EA 2021).

The Local Government Association says of BNG that it:

…delivers measurable improvements for biodiversity by creating or enhancing habitats in association with development. Biodiversity net gain can be achieved on-site, off-site or through a combination of on-site and off-site measures.[4]

GOV.UK says of the Biodiversity Metric that:

where a development has an impact on biodiversity, it will ensure that the development is delivered in a way which helps to restore any biodiversity loss and seeks to deliver thriving natural spaces for local communities.[5]

This aligns perfectly with Bristol’s recent declarations of climate and ecological emergencies and with the aspirations of the Ecological Emergency Action Plan,[6] which recognises that a BNG of at least 10% net gain will become mandatory for housing and development and acknowledges that:

These strategies [the Local Nature Recovery Strategies] will guide smooth and effective delivery of Biodiversity Net…

Our proposed new BTRS model

We propose that the Bristol Tree Replacement Standard be amended to reflect the requirements of the EA 2021 and BNG 4.0 and that the BTRS table (Table 1 above) be replaced with Table 2 below:

The Replacement Trees Required number is based on the habitat area of each of the three BNG 4.0 tree category sizes (Table 8-1 below) divided by the area habitat of one BNG 4.0 Small category tree (see section 3 below) plus a 10% net gain. This is rounded up to the nearest whole number – you can’t plant a fraction of a tree.

The reasoning for our proposal is set out below.

Applying the Biodiversity Metric to Urban trees

The most recent Biodiversity Metric (BNG 4.0) published by Natural England this April, defines trees in urban spaces as Individual trees called Urban tree habitats. The User Guide states that:

Individual trees may be classed as ‘urban’ or ‘rural’. Typically, urban trees will be bound by (or near) hardstanding and rural trees are likely to be found in open countryside. The assessor should consider the degree of ‘urbanisation’ of habitats around the tree and assign the best fit for the location.

Individual trees may also be found in groups or stands (with overlapping canopies) within and around the perimeter of urban land. This includes those along urban streets, highways, railways and canals, and also former field boundary trees incorporated into developments. For example, if groups of trees within the urban environment do not match the descriptions for woodland, they may be assessed as a block of individual urban trees.

Calculating Individual trees habitat

Table 8-1 in the BNG 4.0 user guide is used to calculate the ‘area equivalent’ of individual trees:

Note that the tree’s stem diameter will still need to be ascertained using BS:5837 2012,[7] and that any tree with a stem diameter (DBH) 7 mm or more and of whatever quality (even a dead tree, which offers its own habitat benefits) is included. Under the current DM17/BTRS requirement, trees with a DBH smaller than 150 mm are excluded, as are BS:5837 2012 category “U” trees. This will no longer be the case.

The Rule 3 of the BNG User guide makes it clear that like-for-like replacement is most often required, so that lost Individual trees (which have Medium distinctiveness) are to be replaced by Individual trees rather than by other habitat types of the same distinctiveness.[8]

Forecasting the post-development habitat area of new Individual trees

The BNG 4.0 User Guide provides this guidance:

8.3.13. Size classes for newly planted trees should be classified by a projected size relevant to the project timeframe.

• most newly planted street trees should be categorised as ‘small’

• evidence is required to justify the input of larger size classes

8.3.14. When estimating the size of planted trees consideration should be given to growth rate, which is determined by a wide range of factors, including tree vigour, geography, soil conditions, sunlight, precipitation levels and temperature.

8.3.15. Do not record natural size increases of pre-existing baseline trees within post-development calculations.

Our calculations are based on ‘small’ category replacement trees being planted.

The likely impact of this policy change

We have analysed tree data for 1,038 surveyed trees taken from a sample of BS:5837 2012 tree surveys submitted in support of previous planning applications. Most of the trees in this sample, 61%, fall within the BNG 4.0 Small range, 38% are within the Medium range, with the balance, 1%, being categorised as Large.

Table 4 below sets out the likely impact of the proposed changes to BTRS. It assumes that all these trees were removed (though that was not the case for all the planning applications we sampled):

The spreadsheet setting out the basis of our calculations can be downloaded here – RPA Table BNG 4.0 8-1 table Comparison.

Our proposed changes to BTRS are set out in Appendix 1.

A copy of this article is available here.

Appendix 1 – Our proposed changes to BTRS

See the Planning Obligations Supplementary Planning Document at page 20.

Trees – Policy Background

The justification for requiring obligations in respect of new or compensatory tree planting is set out in the Environment Act 2021, Policies BCS9 and BCS11 of the Council’s Core Strategy and in DM 17 of the Council’s Site Allocations and Development Management Policies.[9]

Trigger for Obligation

Obligations in respect of trees will be required where there is an obligation under the Environment Act 2021 to compensate for the loss of biodiversity when Urban tree habitat is lost as a result of development.

Any offsite Urban tree habitat creation will take place in sites which are either on open ground or in areas of hard standing such as pavements and are located as close as possible to the site of the lost tree.

Where planting will take place directly into open ground, the contribution will be lower than where the planting is in an area of hard standing. This is because of the need to plant trees located in areas of hard standing in an engineered tree pit.

All tree planting on public land will be undertaken by the council to ensure a consistent approach and level of quality, and to reduce the likelihood of new tree stock failing to survive.

Level of Contribution

The contribution covers the cost of providing the tree pit (where appropriate), purchasing, planting, protecting, establishing and initially maintaining the new tree. The level of contribution per tree is as follows:

  • Tree in open ground (no tree pit required) £765.21
  • Tree in hard standing (tree pit required) £3,318.88[10]

The ‘open ground’ figure will apply where a development results in the loss of Council-owned trees planted in open ground. In these cases, the Council will undertake replacement tree planting in the nearest appropriate area of public open space.

In all other cases, the level of offsite compensation required will be based on the nature (in open ground or in hard standing) of the specific site which will has been identified by the developer and is approved by the Council during the planning approval process. In the absence of any such agreement, the level of contribution will be for a tree in hard standing.

The calculation of the habitat required to compensate for loss of Urban trees is set out in Table 8-1 of the Biodiversity Metric (BNG), published by Natural England. This may be updated as newer versions of BNG become mandatory under the Environment Act 2021.

The following table will be used when calculating the level of contribution required by this obligation:


[1] https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1005759/NPPF_July_2021.pdf

[2] https://www.bristol.gov.uk/files/documents/64-core-strategy-web-pdf-low-res-with-links/file at page 74.

[3] https://www.bristol.gov.uk/files/documents/5718-cd5-2-brislington-meadows-site-allocations-and-development-management-policies/file page 36.

[4] https://www.local.gov.uk/pas/topics/environment/biodiversity-net-gain.

[5] https://www.gov.uk/government/news/biodiversity-30-metric-launched-in-new-sustainable-development-toolkit.

[6] https://www.bristol.gov.uk/documents/20182/5572361/Ecological_Emergency_Action_Plan.pdf/2e98b357-5e7c-d926-3a52-bf602e01d44c?t=1630497102530.

[7] https://knowledge.bsigroup.com/products/trees-in-relation-to-design-demolition-and-construction-recommendations/standard

[8] Table 3-2 Trading rules (Rule 3) to compensate for losses. Any habitat from a higher distinctiveness band (from any broad habitat type) may also be used.

[9] These references may need to be changed to reflect any replacement policies adopted with the new Local Plan.

[10] These values should be updated to the current rates applicable at the time of adoption. The current indexed rates as of May 2023 are £1,143.15 & £4,958.07 respectively.

Our proposal for a new Bristol Tree Replacement Standard

The Bristol Tree Replacement Standard (BTRS), which was adopted nearly a decade ago in 2013, provides a mechanism for calculating the number of replacements for any trees that are removed for developments. It was ground-breaking in its time as it typically required more than 1:1 replacement.

The presumption should always be that trees should be retained. The application of BTRS should only ever be a last resort. It should not be the default choice, which it seems to have become.

The starting point for any decision on whether to remove trees (or any other green asset) is the Mitigation Hierarchy[2] which states, firstly, avoid; then, if that is not possible, minimise; then, if that is not possible, restore; and, as a last resort, compensate (the purpose or BTRS). BCS9 adopts this approach and states that:

Individual green assets should be retained wherever possible and integrated into new developments.

However, with the emergence of a new Local Plan for Bristol, we believe that the time has come for BTRS to be revised to reflect our changing understanding of the vital importance of trees to the city in the years since the last version of the Local Plan was adopted in 2014.

In addition, Bristol has adopted Climate and Ecological Emergency Declarations so a new BTRS will be an important part of implementing these declarations. Nationally, the new Environment Act 2021 (EA 2021) is coming into force late next year.

Our proposal provides a mechanism for complying with the new legal requirement for 10% Biodiversity Net Gain (BNG) which will be mandatory when EA 2021 takes effect.

Background

Under current policy – BCS9 and DM17 – trees lost to development must be replaced using this table:

Table 1 The Current BTRS replacement tree table

However, when the balance of the Environment Act 2021 (EA 2021) takes effect late in 2023, the current version of BTRS will not, in most cases, be sufficient to achieve the 10% biodiversity net gain (BNG) that will be required for nearly all developments. Section 90A will be added to the Town and Country Planning Act 1990 and will set out the level of biodiversity net gain required ( Schedule 14 of the EA 2021).

The Local Government Association says of BNG that it:

…delivers measurable improvements for biodiversity by creating or enhancing habitats in association with development. Biodiversity net gain can be achieved on-site, off-site or through a combination of on-site and off-site measures.[3]

GOV.UK says of the Biodiversity Metric that:

where a development has an impact on biodiversity, it will ensure that the development is delivered in a way which helps to restore any biodiversity loss and seeks to deliver thriving natural spaces for local communities.[4]

This aligns perfectly with Bristol’s recent declarations of climate and ecological emergencies and with the aspirations of the Ecological Emergency Action Plan,[5] which recognises that a BNG of 10% net gain will become mandatory for housing and development and acknowledges that:

These strategies [the Local Nature Recovery Strategies] will guide smooth and effective delivery of Biodiversity Net…

Our proposed new BTRS model

We propose that the Bristol Tree Replacement Standard be amended to reflect the requirements of the EA 2021 and BNG 3.1 and that the BTRS table (Table 1) be replaced with Table 2 below:

Table 2 The proposed new BTRS tree replacement table

The Replacement Trees Required number is based on the habitat area of each of the three BNG 3.1 tree categories (Table 7-2 below) divided by the area habitat of one 30-year old BNG 3.1 Small tree (Table 3 below) plus 10% net gain. This is rounded up to the nearest whole number since you can’t plant a fraction of a tree.

The reasoning for our proposal is set out below:

Applying the Biodiversity Metric to Urban trees

The most recent Biodiversity Metric (BNG 3.1) published by Natural England, defines trees in urban spaces as Urban tree habitats. The guidance states that:

the term ‘Urban tree’ applies to all trees in urban situations. Urban trees may be situated within public land, private land, institutional land and land used for transport functions.

Table 7-1 divides Urban tree habitats into three categories:

Paragraph 8.5 of the 3.1 BNG Guidance makes it clear that lines of trees in an urban environment should not be treated as a linear habitat:

Urban trees are considered separately to lines of trees in the wider environment, since they generally occur in an urban environment surrounded by developed land. 

Calculating Urban tree habitat

Urban tree baseline habitat area is measured in hectares and is based on the Root Protection Area[7] (RPA) of each tree impacted by a proposed development. RPA is used instead of tree canopy because it is considered to be the best proxy for tree biomass.

In most cases, RPA is obtained from an Arboricultural Impact Assessment (AIA), which complies with British Standard 5837 2012 – Trees in relation to design, demolition and construction (BS:5837).

Where no AIA is available, Table 7-2 is used:

Note that the tree’s size will still need to be ascertained, and that any tree with a stem diameter (DBH) 75mm or more and of whatever quality (even a dead tree, which offers its own habitat benefits) is included . Under BTRS, trees with a DBH smaller than 150 mm are excluded, as are BS:5837 category “U” trees.

The guidance also makes it clear that, given the important ecosystem services value provided by trees, where possible like-for-like compensation is the preferred approach, so that lost Urban trees are replaced by Urban trees rather than by other types of urban habitat.[8]

Replacing lost trees

To calculate the number of trees required to replace Urban tree habitat being lost, table 7-2 above is used on this basis:

Size classes for newly planted trees should be classified by projected size at 30 years from planting.

We have used the median DBH sizes for new stock trees as set out in BS 3936-1: Nursery Stock Specification for trees and shrubs as the basis for calculating the eventual size of a newly planted trees after 30 years and assumed that a tree adds 2.54 cm (1”) to its girth annually.

This results in a predicted stock tree size after 30 years’ growth. This is then assigned to one of the three Urban tree categories set out in table 7-2: Small, Medium or Large. In all cases save for Semi-mature tree stock, the eventual size of stock trees after 30 years falls within the BNG 3.1 size category Small, which has a habitat area of 0.0041 hectares. This value is then used to calculate how many new trees will be required to replace trees lost to the development, plus a 10% biodiversity net gain. This gives a compensation size per replacement tree of 0.0045 ha (0.0041 hectares + 10%).

Table 3 below shows the basis our our calculation:

Table 3 Annual stock tree growth predictions

The Trading Rules

It may be that a notional positive biodiversity net gain can be achieved by replacing fewer trees than this analysis indicates. However, this is not enough. The calculation should also comply with the Trading Rules that apply to Urban tree habitats.

Paragraph 7.6 of the 3.1 BNG Guidance states:

The mitigation hierarchy and trading rules apply to Urban trees. Given Urban trees are a ‘Medium’ distinctiveness habitat, trading rules stipulate that the same broad habitat type (or a higher distinctiveness habitat) is required. However, given the important ecosystem services value provided by trees, where possible ‘like for like’ compensation is the preferred approach (i.e. where possible any loss of Urban trees should be replaced by Urban trees – rather than other urban habitats).

Rule 3 of the User Guide states: ‘”Trading down’ must be avoided. Losses of habitat are to be compensated for on a ‘like for like’ or ‘like for better’ basis. New or restored habitats should aim to achieve a higher distinctiveness and/or condition than those lost…’

The likely impact of this policy change

We have analysed tree data for 1,038 surveyed trees taken from a sample of AIAs submitted in support of previous planning applications. Most of the trees in this sample, 61%, fall within the BNG 3.1 Small range, 38% within the Medium range, with the balance, 1%, categorised as Large.

Table 4 below sets out the likely impact of the proposed changes to BTRS. It assumes that all these trees were removed (though that was not the case for all the planning applications we sampled):

Table 4 Proposed BTRS impact analysis

The spreadsheet setting out the basis of our calculations can be downloaded here – RPA Table 7-2 Comparison.

Our proposed changes to BTRS (published in the Planning Obligations Supplementary Planning Document, page 20) are set out in Appendix 1.

This article was amended on 7 November 2022 to include references to Lines of Trees in the urban environment, the application of the Trading Rules to Urban tree habitats and fix a broken link.

Appendix 1

Our proposed changes to BTRS, set out in the Planning Obligations Supplementary Planning Document, page 20.

Trees – Policy Background

The justification for requiring obligations in respect of new or compensatory tree planting is set out in the Environment Act 2021, Policies BCS9 and BCS11 of the Council’s Core Strategy and in DM 17 of the Council’s Site Allocations and Development Management Policies.

Trigger for Obligation

Obligations in respect of trees will be required where there is an obligation under the Environment Act 2021 to compensate for the loss of biodiversity when Urban tree habitat is lost as a result of development.

Any offsite Urban tree habitat creation will take place in sites which are either on open ground or in areas of hard standing such as pavements.

Where planting will take place directly into open ground, the contribution will be lower than where the planting is in an area of hard standing. This is because of the need to plant trees located in areas of hard standing in an engineered tree pit.

All tree planting on public land will be undertaken by the council to ensure a consistent approach and level of quality, and to reduce the likelihood of new tree stock failing to survive.

Level of Contribution

The contribution covers the cost of providing the tree pit (where appropriate), purchasing, planting, protecting, establishing and initially maintaining the new tree. The level of contribution per tree is as follows[9]:

  • Tree in open ground (no tree pit required) £765.21
  • Tree in hard standing (tree pit required) £3,318.88

The ‘open ground’ figure will apply where a development results in the loss of Council-owned trees planted in open ground. In these cases, the Council will undertake replacement tree planting in the nearest appropriate area of public open space.

In all other cases, the level of offsite compensation required will be based on the nature (in open ground or in hard standing) of the specific site which will has been identified by the developer and is approved by the Council during the planning approval process. In the absence of any such agreement, the level of contribution will be for a tree in hard standing.

The calculation of the habitat required to compensate for loss of Urban trees is set out in Table 7-2 of the Biodiversity Metric (BNG), published from time to time by Natural England. This may be updated as newer versions of BNG are published.

The following table will be used when calculating the level of contribution required by this obligation:


A copy of this blog can be downloaded here:

BTF proposal for a new Bristol Tree Replacement Standard


[1] Biodiversity Metric 3.1 – Auditing and accounting for biodiversity – USER GUIDE.

[2] https://nationalzoo.si.edu/ccs/mitigation-hierarchy.

[3] https://www.local.gov.uk/pas/topics/environment/biodiversity-net-gain.

[4] https://www.gov.uk/government/news/biodiversity-30-metric-launched-in-new-sustainable-development-toolkit.

[5] https://www.bristol.gov.uk/documents/20182/5572361/Ecological_Emergency_Action_Plan.pdf/2e98b357-5e7c-d926-3a52-bf602e01d44c?t=1630497102530.

[6] DBH = Diameter at Breast Height. RPAr = Root Protection Area radius. Area = the calculated BNG habitat area.

[7] RPA area = π × r2 where r is 12 x the tree’s DBH for a single stemmed tree. For multi-stemmed trees, the DBH of the largest stem in the cluster should be used to determine r.

GOV.UK advice is that r should be at least 15 times larger than DBH – https://www.gov.uk/guidance/ancient-woodland-ancient-trees-and-veteran-trees-advice-for-making-planning-decisions.

The Woodland Trust also recommends that r be set to 15 x DBH for ancient and veteran trees – https://www.woodlandtrust.org.uk/blog/2021/04/root-protection-areas.

[8] Paragraph 7.8 – Trading Rules.

[9] These values should be updated to the current rates applicable at the time of adoption. The current indexed rates as of April 2022 are £1,041.6 & £4,517.89 respectively.

[10] DBH = Diameter at Breast Height. RPAr = Root Protection Area radius. Area = the calculated BNG habitat area.

Valuing our urban trees – part III

When is tree not a tree?

Figure 1  Leyland cypress trees on the boundary of the former Police Dog & Horse Training Centre, Bristol.

The Biodiversity Metric 3.0 (BNG 3.0) User Guide defines Urban Tree habitats as follows:

Individual TreesYoung trees over 75mm in diameter measured at 1.5m from ground level and individual semi-mature and mature trees of significant stature and size that dominant their surroundings whose canopies are not touching but that are in close proximity to other trees.
Perimeter BlocksGroups or stands of trees within and around boundaries of land, former field boundary trees incorporated into developments, individual trees whose canopies overlap continuously.
Linear BlocksLines of trees along streets, highways, railways and canals whose canopies overlap continuously.

These habitats are measured by area (hectares). Using this measurement and other parameters (Distinctiveness, Condition and Strategic Significance), their baseline biodiversity value is calculated in area biodiversity habitat units (ABHUs).

BNG 3.0 also includes separate calculations for two types of linear habitat, one of which is ‘Hedgerows and Lines of Trees’. These linear habitats are measured in kilometres. Using this measurement and the same parameters used for ABHUs, their baseline biodiversity value is calculated in hedgerow biodiversity units (HBUs).

Hedgerow habitats are a feature almost unique to the British Isles, but ‘Lines of Trees’ have been included as a linear habitat as they ‘display some of the same functional qualities as hedgerows’.

Box 8-2 of the BNG 3.0 User Guide (Figure 2) uses this key to help identify Hedgerow or Line of Trees habitat types:

Figure 2 Box 8.2 – BNG 3.0 User Guide

The BNG 3.0 User Guide states that ‘Urban trees are considered separately to lines of trees in the wider environment, since they generally occur in an urban environment surrounded by developed land’. However, it is possible for disagreements to arise where the site is not clearly part of ‘an urban environment’, even though the trees fall within the Urban Tree habitat definition as either Perimeter or Linear Blocks.

A recent example demonstrates the issue. It involved 34 Leyland cypress trees growing along the boundary of the former Police Dog & Horse Training Centre on Clanage Road, Bristol, on the edge of the city. These trees were planted to form a screen between Clanage Road and the training centre (Figures 1 & 3).

This issue was argued before the Planning Inspector when the Secretary of State called the matter in (APP/Z0116/V/21/3270776) following a grant of planning permission for a change of use to a touring caravan site.

It was agreed at the inquiry that these trees had been planted between 1.5 to 2 metres apart, had developed average stem diameters of 33 cm and had grown to about 10 metres high and eight metres wide. The whole row is about 72 metres (0.072 km) long.

Figure 3 The site on the edge of the city (red boundary line)

Using the flow chart at Box 8-2 above, the developer’s ecologist argued that these trees were a Hedge Ornamental Non-native habitat. So, using the BNG 3.0 calculator, they would be assessed as a linear habitat 0.072 kilometres long. This habitat is given a Very Low Distinctiveness (score 1) and has a Poor Condition (score 1) [1]. Because of its location, it was given a Strategic Significance of Within area formally identified in local strategy (score 1.15). As such, the baseline habitat value is calculated as 0.072 x 1 x 1 x 1.15 = 0.08 HBUs.

We argued that these trees formed an Urban Tree habitat and that, using the BNG 3.0 calculator, it should be treated as 34 Medium-sized trees with a combined area of 0.1384 hectares with a Medium Distinctiveness (score 4) and is in Poor Condition (score 1) – even though it was agreed that the trees were in good condition and could be categorised as B2 using BS 5837:2012. Because of its location, it was given a Strategic Significance of Within area formally identified in local strategy (score 1.15). On this basis, the baseline habitat value is calculated as 0.1384 x 4 x 1 x 1.15 = 0.64 ABHUs (nearly 8 times the HBU value).

Whilst Rule 4 of the BNG 3.0 User Guide (page 37) states that ‘… the three types of biodiversity units generated by this metric (for area, hedgerow and river habitats) are unique and cannot be summed’, it is clear that adopting either of these two approaches will result in very different outcomes when assessing biodiversity net gain.

In our view it is vital not to undervalue baseline habitats by the selective use of the habitat definitions given in BNG 3.0.

The planning inquiry decision (refusal) has now been published – APP/Z0116/V/21/3270776.

A copy of this blog is available here.


Valuing our urban trees – part I

Valuing our urban trees – part II


[1] The Very Low Distinctiveness and Poor Condition parameters are the only options available for this habitat type under BNG 3.0.

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”.’

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’.

A letter to our Councillors

Dear Bristol City Councillors,

We recognise the fundamental importance of the natural environment, the value that nature has in an urban setting and the global threat posed by the ongoing climate catastrophe. We also recognise that trees are a crucial component in all these concerns.

We are supportive of Bristol City Council’s declaration of a Climate Emergency and an Ecological Emergency and the goals detailed in the One City Climate Strategy, including the commitment to carbon neutrality by 2030 and doubling the abundance of wildlife by 2050. We are also supportive of their commitment to doubling the tree canopy by 2046.

However, we have a real concern that the commendable words are not being matched by effective actions.

A principle aim of the BTF is to promote the planting and preservation of trees in Bristol for the well-being of its citizens, the sustainability of urban habitation, the enhancement of nature in the cityscape and as our contribution to combating climate change (see A Manifesto for protecting Bristol’s existing Urban Forest).

A recurrent concern we have is the continued loss of trees as a result of environmentally insensitive developments that are not sympathetic to the City’s declared commitments outlined above. On the other hand, the BTF supports developments that favour a sustainable environment over high density occupancy, and those that prioritise retention of existing trees.

Bristol’s policy on replacing trees lost to development – adhering to the Bristol Tree Replacement Standard (BTRS) – is widely well regarded. As such, decision makers believe that tree loss is mitigated by subsequent tree replacement. However, recent studies undertaken by the BTF have shown that this is not the case over the timescales committed to by Bristol City Council and the Green Party.

Typically, tree planting undertaken under the BTRS takes between 30 and 50 years to recover the biomass (and therefore the CO2e) lost by felling, well beyond the 10-year commitment on carbon neutrality, and even beyond dates set for doubling the tree canopy or doubling wildlife abundance.

The BTF study has been developed into a versatile online tool for calculating the extent and timescale of the carbon deficit, with a wide range of inputs. This can be accessed via the link Tree Carbon Calculator, and we encourage you to try this yourself. See also the BTF blog Tree replacement and carbon neutrality.

In the example shown here, a mature tree felled in 2020 is replaced by four trees (as per BTRS) of the same species. The carbon released (2 tonnes CO2e) is not recovered until 2064, a full 34 years beyond the date Bristol aims to be carbon neutral.

This model can also be used to determine how many replacement trees are needed to recover lost carbon within a particular timescale. In the example shown, to be carbon neutral by 2030, a reasonable expectation as this is the declared aim of BCC, the felled tree would need to be replaced by 37 plantings of the same species. Scaled up to, for instance, 500 trees, new plantings would need to number 18,500 to mitigate the lost carbon.

This new information represents a fundamental change in the evidence base for tree replacements, and emphasises the need to retain existing mature trees, and not to consider replacement by new plantings as adequate mitigation.

We request that you consider this new information with urgency and make a commitment to oppose developments where mature trees are removed and tree replacements do not deliver carbon neutrality by 2030.

A Manifesto for protecting Bristol’s existing Urban Forest

We invite all candidates standing in this May’s Mayoral and Councillor elections to endorse our tree manifesto which we set out here.

Bristol has declared a climate and ecological emergency. An emergency means making radical changes now – in every council department, by every developer, and by all those who own or care for trees.

All these proposals fit under Bristol’s existing 2011 Bristol Development Framework Core Strategy – BCS9 Green Infrastructure Policy which should now be implemented.  We must stop the needless destruction of so many trees in our city and instead learn to work around and with them.

Everyone from all sides of the political spectrum is talking about planting trees.  We fully endorse this, but it will take time for these new trees to mature. In the meantime, retaining existing trees will have the biggest immediate effect.

We propose that

  • There needs to be genuine community engagement in Bristol’s tree management decisions.  The council needs to listen to communities that want to save trees, not just to those who want to remove them.
  • Urban trees (planted or self-sown) have a tough life. Many bear the wounds and scars of previous damage or interventions.  These trees, though they may not be perfect, should be valued for the ecosystem services they provide and retained with appropriate and careful management wherever possible.
  • Alternatives to felling must be given priority, whether for street trees, or for those threatened by planning applications, or for other trees in the public or the private space.  
  • We need to strengthen planning policies to help retain trees on development sites by building around them, especially when the trees are on the edge of the site. 
  • Veteran and ancient trees require specialist management to ensure their retention whenever possible.
  • When surveys identify trees that present a risk, there should be consultation about the range of options available to mitigate the risk. This should always balance risk with the benefits the tree provides. Felling is only ever a last resort.
  • If trees must be felled, then more trees need to be planted to replace them. This should be based on well-established metrics used to calculate how to increase (not just replace) the natural capital of the lost tree.

Click here to print a copy of the manifesto. Candidates are welcome to download and use to support our aims.

Our Blogs contain many examples of the sorts of issues that have caused us to write this manifesto.

%d bloggers like this: