Author: BristolTreeForum

We are a group of volunteers dedicated to increasing the tree canopy cover of Bristol.

Ancient trees, missing data, and the fight over Bristol Airport’s planned expansion

So far, most of the public alarm about this expansion has centred on Felton Common, the well-loved local nature reserve on the other side of the runway, where the airport wants to plant 8.5-metre approach lights and fencing across protected grassland. Campaigners under the Save Felton Common banner have campaigned hard against that ‘land grab’, and rightly so. But the fierce fight over the Common has largely overshadowed a second, quieter yet important threat next door — the loss of irreplaceable habitat at Cook’s Farm, which has drawn far less attention. That is what our objection is chiefly concerned with.

Bristol Airport wants to grow. Its planning application (ref. 26/P/0686/OU2) seeks permission to expand from 12 million passengers a year to 15 million. To do this, the airport needs more land — including Cook’s Farm, some 24 hectares of long-established agricultural countryside where hedgerows have stood since at least the 1840s and where some trees have been growing for centuries. The airport now proposes to compulsorily purchase the site so it can carry out its plans.

However, it first needs to persuade the planners that its proposal is acceptable. We say it’s not, and we’ve lodged a detailed objection. It is a technical document, full of hectares and habitat codes, but underneath the detail is a simple story: irreplaceable habitat is at risk, the evidence supporting the plans doesn’t add up, and the law says that should matter.

Here is what our objection says, in plain terms.

The heart of it: three veteran trees

The most emotive part of the case concerns three veteran trees growing in an ancient hedgerow on the boundary of Cook’s Farm — two Ash and one Sycamore. The airport doesn’t propose to simply cut them down. Instead, it plans to translocate them: lift them with a giant tree spade and replant them on the northern edge of the development.

That might sound like a reasonable compromise, but our objections explain why it’s not in careful detail.

A veteran tree isn’t just an old tree, especially those in long-established hedgerows. It’s a whole ecosystem — cavities, rot, deadwood and fungal growth that specialist insects, fungi and other wildlife depend on and cannot find anywhere else. These features take centuries to form. You cannot manufacture them, and you cannot move them.

Worse, veteran trees are extremely unlikely to survive being moved. Their biology works against them. Over centuries they’ve spent their reserves coping with drought, storms, disease and damage, leaving little in the tank to survive the shock of relocation. Their roots are extensive but fragile, they depend on specialised underground fungal networks built up over generations, and much of their internal wood is effectively dead but structurally essential — it can’t be repaired if damaged. Successful relocation needs around two full growing seasons of careful root preparation beforehand. Crucially, the airport’s plan makes no proposal to reduce the trees’ roots at all. As our objection bluntly puts it: if the trees are translocated without root reduction, they will die.

Our conclusion is that, for the purposes of a planning decision, these three veteran trees should be treated as lost. The airport itself seems to half-accept this: it promises a ‘compensation’ package of ten new future veteran trees and the artificial ‘veteranisation’ of ten existing trees. But you can’t conjure a veteran tree on demand. Even with the right conditions, it takes two or three decades for a ‘veteranised’ tree to start resembling the real thing — and it will still lack the fungal decay that gives a true veteran its ecological value.

The evidence doesn’t add up

Beyond the trees themselves, we found that the environmental evidence supporting the application is riddled with inconsistencies. This means that the application can’t properly be decided as it stands.

The airport is required to demonstrate that it will deliver ‘Biodiversity Net Gain’ — a calculation meant to prove development leaves nature in a measurably better state (at least 10%) than it was before development. But our objection shows the numbers in the official metric calculation simply don’t match the airport’s own ecological survey. The two documents use different habitat categories, different reference codes, and don’t cross-reference each other. Some habitats that appear in the survey are missing from the metric altogether. Habitat parcels aren’t sized, and their locations aren’t shown on the map. In short, it’s impossible to reconcile the airport’s own datasets.

The tree surveys are a particular problem. Three surveys tucked into the appendices fail to meet BS5837:2012, the British Standard for trees in planning. Between them they’re missing the surveyors’ names and qualifications, survey dates, crown-spread data, branch heights and directions, life-expectancy estimates, soil assessments, and even the number of trees in some groups. One key survey dates from June 2024 and is now out of date. And when we asked for the tree schedule in a usable spreadsheet format so we could check it, our request was refused — leaving them, in their words, to analyse the data ‘as best we can’.

Even working with that inadequate evidence, their interim analysis is striking. Of roughly 1,618 individual trees on the site, some 367 — more than a fifth — are set to be removed, along with a share of the site’s hedgerows, which the airport’s own figures and the survey record in wildly different numbers (10 hedgerow parcels in one document, 71 in another).

Why this is a matter of law, not just sentiment

This is where our objection turns from ecology to policy — and it’s the part that could decide the outcome.

National planning rules are clear about irreplaceable habitats. Paragraph 193(c) of the National Planning Policy Framework says development that causes the loss or deterioration of irreplaceable habitats — and it names ancient and veteran trees specifically — ‘should be refused, unless there are wholly exceptional reasons and a suitable compensation strategy exists’.

We make two arguments about this test:

  • First, it’s a two-part test that has to be met in sequence: you need both wholly exceptional reasons and a suitable compensation strategy. A compensation package — however good, and here they say it isn’t good — cannot on its own make the reasons ‘wholly exceptional’. The decision in Juden v London Borough of Tower Hamlets [2021] EWHC 1368 (Admin) backs this interpretation.
  • Second, we argue that this scheme doesn’t clear the ‘wholly exceptional’ bar at all. The Framework’s own example of exceptional reasons is nationally significant infrastructure — the kind of once-in-a-generation project decided by government. This application, we say, is simply about increasing the capacity of an existing airport. That’s not the sort of wholly exceptional circumstance the rules have in mind.

Our objection also points to local policy. North Somerset Council’s own adopted Core Strategy (Policy CS4) requires it to protect, connect and enhance important habitats, ‘particularly designated sites, ancient woodlands and veteran trees’. The same protection is included in the Council’s emerging 2041 Local Plan. Approving the loss of these veteran trees would go against the Council’s own rules.

What it comes down to

Strip away the appendices and the acronyms, and our case is straightforward. The airport wants to expand on to land that includes centuries-old, irreplaceable habitat. Its plan to ‘move’ three veteran trees is, on the evidence, a plan to kill them slowly. The paperwork meant to justify all this is inconsistent, incomplete and in places non-compliant with the relevant standards. National and local planning policy both say irreplaceable habitat like this should be protected, not traded away for extra passenger numbers.

Our central demand is modest but firm: these problems need to be resolved before the application can properly be decided. For anyone who cares about Cook’s Farm, its ancient hedgerows and the veteran trees growing in them, that’s the line worth holding.

Here is our full response to the application:

BTF Consolidated Comments – 06 May 2026

Why trees keep drawing the short straw in the new nature rules

We’ve written before about the rule change that, from 6 August 2026, lets the smallest building sites skip the ‘leave nature better off’ requirement. But that small-sites exemption is only one of several changes on the way to the same set of nature rules. Taken together, they keep landing on the same casualty: the everyday trees growing on our streets, and in our parks and gardens.

Here is why trees, in particular, keep losing out.

Trees are the odd one out

Most habitats the BNG rules deal with — grassland, scrub, hedgerows etc. — can, in principle, be recreated somewhere else within a few years.

Plant a replacement tree for one felled and it starts life as a sapling and will take (assuming it lives long enough) years to do what the felled tree was already doing: a mature tree takes decades to mature and at least nine saplings to replace just one. The largest trees would need at least 19 new trees and still take many years to ‘replace’.

And a tree’s real value — the shade and cleaner air it provides us, soaking up rainfall, its character and the nature it shelters that you see daily — is delivered exactly where it stands. Move the ‘replacement’ to a distant field few will ever visit and, while you may have ‘ticked the replacement box’, you have lost the thing that mattered – your local, everyday tree.

That is the backdrop to the changes now coming.

Clearing trees here, ‘making up for it’ miles away

For slightly larger sites, one proposal would let developers skip trying to keep trees on the site and instead allow them to pay for replacement habitat (not necessarily trees) somewhere else — potentially a long way off. The mature tree that was growing near you, ‘replaced’ by a patch of new grassland or scrub far away in some ‘foreign field’ you cannot visit. The paperwork balances but your tree is gone.

A much bigger exemption for brownfield sites

This could be the big one for towns and cities. The Government has floated exempting brownfield sites of up to 2.5 hectares — more than ten times the size of the small-sites limit. Brownfield and urban plots are exactly where many mature street trees grow, so an exemption on that scale could wave through a lot of tree loss. It is still just a proposal and a final decision is awaited, but the threat is real.

‘Temporary’ felling that lasts forever

Another idea would exempt “temporary” development — anything that can put back within five years. That may be fine for many habitats, but not for trees: you cannot regrow a mature tree in five years. Fell it for a short-term purpose and it is gone for good.

Trees removed in the name of nature

One proposed exemption covers work to improve parks, playing fields and public gardens, or projects whose main aim is to help wildlife. Well meant — but these are often the places where big, mature trees grow. If the ‘improvement’ means cutting trees down — for example, to create open grassland or a play space — there would be no obligation to plant replacements.

Why it adds up

On their own, each of these is a small technical tweak. Together, they push in one direction: it becomes easier to remove the trees closest to where people live, and to offset them — if at all — with habitat elsewhere. The result, over time, is fewer trees in our neighbourhoods and the inevitable ‘greying’ of our urban spaces.

The older protections for trees still stand — Tree Preservation Orders, conservation-area rules, and protection for ancient and veteran trees — along with any local tree protection policies your council has adopted, but these are not always fully applied. Even so, this is exactly why these protections will matter more than ever.

Read the full briefing note here

Our earlier companion post is also available here – The small-sites rule change that could quietly cost your neighbourhood its trees

The small-sites rule change that could quietly cost your neighbourhood its trees

From 6 August 2026, a change to the planning rules takes effect that most people will never hear about — but it could reshape the trees on our streets, in our gardens and on the small plots being built on all over the country.

Here is the short version.

What is changing

When land is developed, the law has, since 2024, usually required a small boost to nature — a “Biodiversity Net Gain” of at least 10%. In plain terms, a development is meant to leave nature a little better off than it found it.

From 6 August, the smallest sites — those of 0.2 hectares or less (about 2,000 square metres, roughly a third of a football pitch, or a small cluster of houses and their gardens) — no longer have to do this at all.

For hard-pressed small builders, that is a welcome simplification. But there is a catch for trees.

Why trees are caught in the middle

Under the old rules, removing even a single tree was usually enough to bring a small project into the nature-boost system — because of the way a tree’s protected “footprint” is measured. In practice, that meant a developer could not quietly fell a tree on a small plot without having to make good the loss.

The new rule swaps that “what is the impact?” test for a much simpler “how big is the site?” test. If the site is 0.2 hectares or smaller, the nature rules simply do not apply — however many trees are cleared.

What that means on the ground

On a site right at the new limit, the equivalent of up to 48 small trees — or around a dozen mature ones — could be removed with no requirement to replace or compensate for them under this system. And the trees most exposed are exactly the ones we tend to notice most: established trees on small urban and infill plots.

What still protects trees

It is not a free-for-all. Tree Preservation Orders, conservation-area rules and the special protections for ancient and veteran trees all still apply — they sit entirely outside this change. Some councils also have their own local tree policies: Bristol’s Tree Replacement Standard, for example, still requires replacement planting whatever the new exemption says.

The snag is that these local protections only exist where a council has actually put them in place — and not every council has.

Why it matters

The change is a sensible piece of red-tape reduction for small builders. But it is also, almost by accident, a real step back for the everyday trees that give our neighbourhoods shade, character and wildlife. From August, whether the trees near you are protected will depend less on national nature rules and more on whether your council has its own policies — and on whether a particular tree happens to be covered by an order.

If you value the trees around you, it is worth asking your local council what protections are in place.

We have set out the full detail — the mechanics, the legal position, and what to watch next — in an accompanying briefing note.

Read the full briefing note here.

St Philip’s Marsh: do the green space sums add up?

Bristol’s biggest regeneration plan promises parks within a five-minute walk of every front door. We measured the plan’s own drawings to see whether the promise holds. Here’s what we found.

St Philip’s Marsh is about to become the new place in Bristol to live, work and study. The draft Masterplan, created by the Bristol Temple Quarter Partnership is now out for consultation. It proposes at least 7,000 homes — for roughly 15,000 people — on 94 hectares of old industrial land east of Temple Meads, plus workspace for thousands of jobs and student housing beside the university’s new campus. For an area with almost no publicly accessible green space currently, the Masterplan’s vision of parks, green streets and riverside walks is most welcome, and we want it to succeed.

However, when we measured the plan’s own drawings — every park, square and green corridor, checked against the Council’s own GIS records — the numbers put forward started to wobble.

A table that vanished

The Masterplan’s headline is 22.4 hectares of open space and green corridors, including 8.1 hectares of ‘new open space’. Curiously, the published figure that should show this breakdown contains no numbers at all. The arithmetic survives only in the figure’s hidden accessibility text — the description read aloud by screen readers. This refers to a quantification table ‘overlaid on the side of the plan’. However, this table was removed before publication, and nobody has updated the hidden text. Our own measurements confirm the totals are correctly computed. So why take the table out?

How big is Sparke Evans Park? Pick a number

The document gives three different sizes for the area’s only existing park, Sparke Evans Park: 2.9 hectares in the body text, 2.5 in the hidden arithmetic, and 2.34 as drawn. The Council’s own GIS records 2.3416 ha. A small thing, perhaps — but the body text overstates the park by 24%, which is the baseline everything else is measured from.

A bigger question is how large is the site itself? The Masterplan never says. Its drawn boundary encloses 94 hectares but the council’s investment website says St Philip’s Marsh totals 65 hectares. Nobody reconciles the two. This is important as the site area is the denominator for the plan’s flagship promise of 25% tree canopy. 25% of which number?

What actually counts as a park?

Bristol’s Parks and Green Spaces Strategy is clear that ‘public realm’ — squares, promenades, landscaped frontages — does not count as open space for recreation. Strip those out of the Masterplan’s 8.1 hectares and the qualifying provision shrinks to somewhere between 5 and 6.6 hectares, most generously counted — and only around 2.6 to 4.3 hectares of it is new. The real new parks are two: Chapel Park (1.26 ha) and Fruit Market Park (about 1.3–1.5 ha). Each is roughly the size of College Green. Between them and Sparke Evans Park, they are expected to host school play, neighbourhood events, ecology, gardens and the daily recreation of thousands.

The density arithmetic nobody has published

Bristol’s adopted standard for the city centre zone is 7.75 m² of recreational open space per person — itself barely a quarter of the 33 m² the average Bristolian enjoys citywide. Working through the strategy’s published figures shows that standard has been set with zero headroom: it assumes the central area’s population will rise 65%, offset by just 2.9 hectares of new green space, landing exactly on the 7.75 m² standard adopted.

The St Philip’s Marsh residents will get roughly 3.3 to 4.4 m² of qualifying green space per person on site, about one tenth of the citywide average. And that’s before you include the daytime population, who will share the same spaces: a workforce of 5,000 or more, several thousand students, and those whom the plan rightly invites in, living nearby in The Dings, Barton Hill, Totterdown and Redcliffe — some of the most green-space-deprived communities in Bristol. If the Masterplan’s population exceeds what the strategy assumed — and its unpublished assumptions are a question we’ve put to the Council — the adopted standard is breached simply by the arithmetic.

Five-minute-walk — from the front door, or the tenth floor?

We modelled walk times over the plan’s own street network. The average journey to the nearest named park is about three minutes. This supports the five-minute-walk promise. However, with roughly one in five residents living above the fifth floor in residential towers of ten storeys and more, this will add to the walk time just getting to the ground before setting off. For those households the five-minute promise quickly becomes longer. Sparke Evans Park, in the south-east of the site, is up to 21 minutes from the far north-west corner, while parts of the employment area are 7–10 minutes from any named park.

And five minutes for whom? The plan’s promise assumes a brisk walker covering 400 metres in five minutes. Bristol’s own parks standard describes that same 400 metres as a nine-minute walk — the pace of older people, small children, anyone with a buggy or those whose walking is impaired: exactly the people who parks matter most for. At that pace, every estimate above roughly doubles, and the far corner of the site is nearly 40 minutes from Sparke Evans Park. The five-minute-walk promise is really a 400-metre promise — which should be judged at the speed of the slowest, not the fastest.

Three thousand trees, ready by the 2050s?

The 25% canopy pledge needs 16–19 hectares of new tree canopy: in the order of 3,000 trees. These will largely be planted on streets that must also fit cycleways, drainage and utilities — creating a near-continuous tree ceiling over two-thirds of the public realm. Newly planted trees would deliver under 1% of site canopy on day one and take 25–40 years to mature, on top of the 20 years needed to complete the development. The 25% canopy pledge currently has no target date, no baseline and no monitoring. So for the first couple of decades, a resident on, say, the tenth floor will look down on saplings, not canopy — exactly what the international 3/30/300 benchmark (3 visible trees, 30% canopy, green space within 300 m) aims to prevent.

What we’re asking for

Our submission makes a series of specific requests, including:

  1. Correct the ambiguous reported park sizes.
  2. Reinstate the vanished quantification table.
  3. State the definitive site area and publish the boundary as open GIS data.
  4. Publish a schedule of open space that distinguishes real recreational space from public realm space, and test this against the projected full daytime population.
  5. Publish the population assumptions behind the quantity standard.
  6. Put a date, baseline, funding and monitoring regime on the canopy pledge.
  7. Front-load tree planting.
  8. Adopt 3/30/300 at design-code stage.
  9. Explain how and when the riverside open spaces will be delivered, given their dependency on the Avon Riversides 2100 flood defence programme — for which £88m has been identified against a further £128m still required.

None of this requires redrawing the plan. It just requires the Partnership to show its workings — because on green space, the difference between a promise and a number is where communities lose out, one planning application at a time.

One last thing. This document was meant to be a Supplementary Planning Document — statutory guidance sitting alongside the Local Plan. A change in Government regulations earlier this year means it will now be adopted only as an “endorsed Masterplan”: non-statutory guidance that developers must merely “have regard to”. That makes everything above more fragile, which is why our submission also asks for the green space framework to be secured through Local Plan policy wording, where it will have legal force.

The consultation closes on 28 July 2026. You can respond through the council’s survey or by emailing: hello@bristoltemplequarter.com — and if green space in this new piece of Bristol matters to you, please do.

Read our submission, with methods and maps, here:

SPM Masterplan Consultation – BTF Response

Analysis for this submission included independent measurement of the Masterplan’s Figure 07.34, georeferenced against Bristol City Council GIS data, and walk-time modelling over the illustrative street network, carried out with AI assistance (Claude, Anthropic) under our direction. Methods are set out in full in the submission’s annex.

The Local Nature Recovery Strategy and Bristol: a reassessment

In January 2025 we argued that the West of England Local Nature Recovery Strategy (LNRS) would do little to improve biodiversity net gain (BNG) in proposed development sites in Bristol. Since then, three things have changed enough to warrant a second look:

A follow-up to our January 2025 post, The Local Nature Recovery Strategy fails to deliver for Bristol.

  1. The emerging Bristol Local Plan has moved to the final stages of the public examination and the timetable for the 2045 Local Plan has been published.
  2. The West of England Mayoral Combined Authority (WECA) has published detailed guidance for developers and ecologists.
  3. We have been able to measure how much of the city the LNRS focus areas cover.

    These three changes mean that the picture is now more nuanced than a simple ‘fails to deliver’, but the practical conclusion is broadly the same. This post sets out why.

    What the latest LNRS has now made explicit

    WECA’s guide for planners, ecologists and developers, together with a dedicated BNG strategic-significance map, now spells out how the 15% Strategic Significance Multiplier uplift is meant to work. To attract the uplift, a proposed intervention must be in a mapped focus area for nature recovery and deliver a measure recommended (mapped) for that location.

    Two points in that guidance are worth dwelling on, because they confirm the argument we made in 2025 — this time in WECA’s own words.

    First, on baseline habitats. Our January post relied on Defra’s position that the multiplier applies only to habitats created or enhanced after development, not to what’s already on site – the baseline habitat. WECA’s FAQ now states this directly: the multiplier ‘is never applied to baseline habitats in the BNG Metric’. That is significant: it means the strategy can never reward the retention of existing habitat on a development site; but only new or enhanced habitats, and then only where a matching measure is mapped.

    Second, on where the mechanism is aimed. The single worked example in WECA’s guide is a developer purchasing off-site BNG units in a focus area. That’s a fair reflection of how the uplift is designed to behave: it’s a tool for steering off-site compensation and habitat banking towards priority locations, not something that typically assists the onsite footprint of a development itself.

    How much of Bristol is a focus area?

    In January we said it was ‘hard to imagine’ the LNRS helping on most Bristol sites, but we did not put a number on the coverage. We have now done so, using WECA’s own published data.

    Taking the Combined Authority’s mapped focus-area layer and clipping it to the official Bristol City Council boundary, 24.2% of the city — roughly 2,640 hectares of its 109 km² — lies within a focus area for nature recovery. (We checked the figure in two independent ways: a regular sampling grid and a random sample of over 90,000 points; both give 24.2%, and the method reproduces the city’s official area to within half a percent.)

    This is not a trivial share; anyone tempted to say the LNRS ‘barely touches’ Bristol should note that nearly a quarter of the city sits inside a focus area. But coverage is the wrong thing to count. That 24.2% is a ceiling — the maximum extent over which the multiplier could ever apply — before two much tighter filters are applied: the habitat being created or enhanced must match a measure mapped for that spot, and none of it can be baseline habitat.

    Coverage is not opportunity

    The more telling question is what is mapped, and where. When we count the individual measures that fall within the Bristol boundary, the focus areas turn out to be almost entirely watercourses and existing public green space that’s unlikely ever to be developed.

    LNRS measures mapped within the Bristol City boundary. Management/enhancement of existing habitat and watercourses (teal) dominates; new-habitat creation measures a developer could deliver on a site (amber) are comparatively few.

    River and floodplain measures dominate, followed by public parks & green space management and hedgerow, scrub and woodland under management. These are overwhelmingly measures for the management, restoration or enhancement of habitat that already exists — mostly along the Avon and Frome corridors, in the city’s parks, and on railway and river margins. This is land that is unlikely ever to be developed and, under the BNG regime, cannot be used to offset on-site habitat losses; BNG offsets may only be provided by registered Biodiversity Gain Sites (BGS). There are six in the LNRS but, currently, none are in Bristol.

    By contrast, the measures a developer might be able to deliver as new habitat on a site — creating woodland, hedgerows, wildflower meadow or mosaic habitat — appear only in the low tens of features and are themselves largely tied to the same green and blue corridors. So, the headline coverage figure and the practical opportunity point in opposite directions: a quarter of the city is mapped, yet the fraction of developable land where a scheme could both sit in a focus area and deliver a matching biodiversity improvement remains very small.

    The planning picture

    The wider planning position has moved on since January 2025, though not in a way that resolves the problem we identified at the time.

    Bristol’s emerging Local Plan completed its examination hearings last year with the final consultation has just completed. We are expecting the inspectors’ final report in the autumn so the plan is not yet adopted and still may not be. In the meantime, the Council having just published the timetable for the 2045 Local Plan which, when it starts this September, will not be completed until April 2029 at the earliest.

    Despite this, the two things we flagged in January still stand. No commitment has yet been made to designate any of Bristol’s focus-area sites — its parks, river corridors and green margins as BGSs available for off-site habitat mitigation — one route by which the uplift could be applied. Central Government has still not issued guidance on the role of the LNRS in planning decisions even though the Levelling-up and Regeneration Act requires plans to ‘take account’ of it. Until that guidance arrives, the strategy’s weight in day-to-day planning remains as defined under the BNG regime.

    Conclusion

    The LNRS is better documented than it was a year ago, and WECA deserves credit for setting out the mechanics clearly. On the specific question we raised in January 2025, that guidance has, if anything, confirmed our reading at the time: the multiplier cannot reward existing habitat. It is built for off-site delivery in priority locations rather than for the sites where most Bristol development happens. As none of these locations in the city are BGS sites, it is practically impossible to apply the 15% uplift they provide.

    The new coverage figure sharpens rather than softens the point. Yes, a quarter of the city is mapped as a focus area — but that land is the Avon, the Frome, in parks or railway land, all of which are already managed and enhanced in place. For a developer weighing up a site in Bristol, the chance that the strategy changes their BNG arithmetic is still low and, where it does, it will usually be through habitat bought outside the city.

    If the LNRS is to deliver the benefits promised for nature in Bristol, the gap is not in the mapping but in the mechanism: making suitable focus-area land available for off-site mitigation, and — as we suggested in January — allowing the city’s own adopted strategies, from its ecological network to its tree and green-space plans, to carry strategic significance where the LNRS does not.

    We suspect that this analysis is also likely to apply to other urban areas across England.

    Our earlier explanation of how strategic significance is assessed is set out in Assessing habitat parcels: strategic significance explained. Coverage and measure figures in this post were derived from the West of England Combined Authority’s LNRS layers on its Open Data Portal, clipped to the Bristol City Council boundary (ONS code E06000023), July 2026.

    Analytical research, policy review and initial drafting were undertaken with the assistance of Claude (Anthropic, 2025). All technical conclusions and professional judgements are those of the author.

    Understanding Biodiversity Gain Plans

    Since BNG became mandatory in February 2024, qualifying developments in England must show how they will deliver at least a 10% gain, to be set out in a Biodiversity Gain Plan (BGP) submitted to the local planning authority. We’ve transcribed 160 BGPs from 21 LPAs into a single, comparable dataset.

    What the data shows so far:

    • Just over under 60% (95 of 160) deliver their gain entirely on site. Another 34 use a mix of on-site and off-site measures, while 17 rely wholly on off-site units and 14 did not state an approach. Two bought Statutory Credits.
    • Off-site reliance is a recurring theme. A number of plans record an on-site biodiversity loss offset by purchased habitat units — a legitimate route, but one that moves the gain away from the community where the development happens.
    • Net gain has to be met habitat type by habitat type (area, hedgerow, watercourse), not as a single blended figure. Several plans that pass overall are marginal — or fall short — on an individual module.

    Accessing this data was harder than it should be:

    • There is no central register of gain plans – why can’t Defra or Natural England include them in their BGS allocation dataset? These documents should be easily accessible.
    • Each council’s portal has to be searched separately, with no consistent way of identifying the relevant application. Only a few authorities (City of York, Bristol and Cotswold among them) have a dedicated application category for BNG discharges. Otherwise the BGPs sit inside generic “discharge of conditions” applications and are very difficult to find.
    • BGPs are produced in a variety of forms – as clean PDFs, fillable forms, bespoke versions or scanned images requiring OCR – which is challenging, especially if they are hand-written.
    • They are often internally inconsistent: off-site figures just copied from the on-site section, credits confused with habitat-bank units, or headline numbers that do not reconcile.
    • Off-site claims frequently differ from what the Biodiversity Gain Sites register records as allocated.
    • Many applications do not include the required BNG Metric calculation.
    • Some applications can’t be analysed because all that is produced (and approved) is the certificate of the off-site HU purchase – and sometimes not even that. As a result, we’ve been unable to include these in our analysis.

    The information exists, but we can only conclude that the planning approval process makes meaningful public scrutiny far harder than it needs to be. Using the available standard Defra form and creating a single searchable register of BGPs would be a straightforward improvement.

    The full dataset and analysis are here — comments, corrections and more data are welcome:

    https://docs.google.com/spreadsheets/d/1iHWWWN2NBo2hpcqW4CAAGjkfLTbZr9Y3/edit?pli=1&gid=1095363016#gid=1095363016

    NB. This analysis will grow as we add more data.

    #BiodiversityNetGain #BNG #BGS #Planning #Nature #Transparency

    Losing our Local Green Space designations

    Are councils protecting our local green spaces? Our research reveals a worrying picture.

    Parks, playing fields, village greens and community orchards are vital for our wellbeing — places where children play, neighbours meet, and nature finds a foothold in our towns and cities. Yet our research suggests that many local councils are failing to use the powers available to them to protect these spaces, leaving them vulnerable to development and neglect.

    How we did our research

    Using Freedom of Information laws, we contacted 62 Local Planning Authorities (LPAs) across England, asking whether their current local plan includes policies protecting Local Green Space (LGS) sites, as set out in the National Planning Policy Framework (NPPF). We also asked them whether any new local plan would do so.

    The LGS designation was introduced in the NPPF in 2012 to give communities the power to protect the green areas that matter most to them. It remains part of national planning policy, and councils are expected to consider it when drawing up local plans.

    Of the 62 requests sent, 55 councils have responded (88%). Eight told us they don’t hold this information. That left 47 substantive responses from councils with real power over local green space protection. Eight councils have yet to respond. The full collated responses are available online.

    What we found: current local plans

    Of the 47 councils that gave a substantive answer, 17 — 36% — confirmed that their current local plan includes LGS policies in line with the NPPF. Twenty-three said their current plan does not, mainly because it predates the NPPF (2012). Bromsgrove, Redditch and Stoke-on-Trent all have plans dating back to 2009/2011 and so that lack LGS provisions, though Stoke’s does contain general green space protections.

    A further six councils gave qualified answers. South Hams, Stoke-on-Trent, Torbay and West Devon noted that designation of specific LGS sites has largely been left to Neighbourhood Plans. Solihull had adopted both an LGS policy and seven Neighbourhood Plans had also adopted their own LGS policies. This is a permitted approach, but one that places the burden on local communities rather than the council.

    What we found: future local plans

    The picture for future plans is only marginally better. Of the 47 substantive respondents, only 12 — 28% — gave an unqualified yes to designating LGS in their new or emerging local plan: Cheltenham, East Devon, Tewkesbury, Cannock Chase, Cotswold, Gloucester City, Bath and North East Somerset, Cornwall, North Somerset, Stratford-on-Avon, Swindon and Wyre Forest. Cotswold confirmed its 2025–43 plan will contain new LGS sites; Bath and North East Somerset (BaNES) proposes retaining and expanding its LGS policy, subject to Cabinet approval, and Stoke-on-Trent’s emerging plan contains LGS designations, a positive step for a city whose current plan predates the 2012 NPPF.

    A further nine councils said they do not intend to designate LGS at all. Birmingham will continue using strategic, criteria-based policies rather than site-specific designations. Tamworth explicitly ruled out using LGS designations, citing limited space and preferring broader open space policies. Rugby says its emerging plan ‘defers to national planning policy’, and South Gloucestershire, despite having LGS policies in its current plan, will drop them from its new one. Broader open space policies offer some protection, but not the strong protection that LGS provides.

    The largest group — 23 councils — said it was too early to tell or that no decision had been made, reflecting how slowly local plan preparation moves. Bournemouth, Christchurch and Poole, for instance, won’t be scoping consultation until June 2026.

    Solihull is currently working on a new Local Plan, and will be reviewing the status of Local Green Space sites and whether there will be any amendments or additions to these.

    The Bristol case: a warning from the front line

    Bristol offers a stark illustration of what’s at stake. While our FOI research was under way, Bristol City Council, at the request of the examining inspectors, was removing all Local Green Space designations from its emerging local plan. Its current plan had included policy GI1, designating LGS sites identified through years of community consultation involving residents, community groups and the Bristol Parks Forum (BPF), with a matrix showing how each site met the NPPF criteria.

    During examination, the inspectors rejected all proposed LGS designations as ‘not considered to be justified or effective,’ so the Council removed the policy entirely. BPF objects, pointing out that 14 sites met all five NPPF criteria and a further 27 met four, yet the Inspector rejected all designations en masse without considering the individual merits of each proposed site. BPF describe this as ‘a real disservice to the people of Bristol.’

    The Council argues Bristol’s green spaces will still be protected through ‘Reserved Open Spaces’ (now call ‘Protected Open Space’ (POS)) status, but both we and BPF reject this as inadequate. POS does not carry the same weight or permanence as LGS. Other cited designations, such as Site of Nature Conservation Interest (SNCI) status, will offer weakened protection in the new proposed local plan. BPF cites Brislington Meadows as an example of a site that lost out despite its status as an SNCI. BPF says:

    The only robust long-term protection for our locally important green spaces against development is to give a site Local Green Space designation. For a city like Bristol to have none is unbelievable.

    Notably, Bristol’s FOI response makes no mention of this removal, instead stating that under the new system introduced by the new Levelling Up and Regeneration Act 2023 (LURA), it has ‘not yet decided’ whether its new local plan will designate LGS sites.

    Both we and BPF are calling for the LGS policy and the proposed designations to be reinstated until a future local plan can provide equivalent or better protection, warning that any gap between local plans will leave green spaces exposed to development with no adequate defence.

    LURA: a planning system in transition

    Under LURA, there’s a transition deadline: plans submitted under the old system must be published by 31 December 2026. Authorities that fail to do this must use LURA’s streamlined 30-month timetable instead ­­— roughly half the current time required.

    This is, in principle, an opportunity: many councils currently without LGS policies are operating under plans that predate the NPPF, and the obligation to produce a new plan forces the issue. But the compressed timetable, reduced consultation, and a shift of generic policies to national level all create conditions in which LGS designation could be marginalised or skipped. The Bristol example, where the Inspectors rejected all proposed LGS designations en masse, demonstrates this.

    The role of Neighbourhood Plans

    Local Green Space designation has often been left to Neighbourhood Plans rather than local plans. Bristol, Plymouth, Torridge, Torbay, Rugby, Solihull and Newcastle-under-Lyme all have made Neighbourhood Plans designating LGS, even where their local plan does not. These designations carry real weight, but Neighbourhood Plans require significant community time and resource. Relying on them risks a two-tier system where well-resourced communities can protect their green spaces but those with fewer resources cannot.

    Why these issues matter

    Bristol is a symptom of a wider problem. Access to good-quality green space improves mental and physical health, supports biodiversity, helps manage flood risk, and strengthens community cohesion. In cities like Bristol — which declared an Ecological Emergency in 2019 and is involved in nature recovery initiatives — densification without adequate green space protection directly contradicts those commitments. When councils fail to use the tools available, a community may find itself powerless to save a local green space, sometimes valued for generations, once a development application arrives.

    What needs to change

    Councils preparing new local plans should treat LGS designation as a core part of the process, not an optional extra, and should engage residents early on which spaces matter most. The Planning Inspectorate should also assess LGS proposals on their individual merits rather than rejecting them wholesale, as happened in Bristol. Councils currently reviewing plans that predate the NPPF have a clear opportunity to put this right.

    What you can do

    • Get involved in your local plan consultation and make the case for LGS designation — and if your council is proposing to remove or weaken protections, say so clearly.
    • Ask your councillors whether your local plan protects local green spaces and what they’re doing about it.
    • Explore Neighbourhood Planning, which gives communities the power to designate LGS directly and may, in some cases, come with government funding.
    • Engage with council open-space strategies and green infrastructure reviews to help build the evidence base for future designations.
    • Support your local parks forum: organisations like the Bristol Parks Forum hold councils to account and amplify community voices. If your area doesn’t have one, consider helping to start one.

    The places where we walk, play, breathe and connect with each other and with nature are worth fighting for — but only if we use the planning system’s tools, hold councils to account, and make sure that our communities are genuinely heard.

    Speaking up for Bristol

    The last opportunity for us to comment on Bristol’s proposed local plan has now passed, so all we can now do is hope that the Inspectors change their minds and reverse their decision to revoke all proposed LGS designations.

    In any event, the Council assures us that it will publish its timetable for a further new local plan, as required under the new LURCA regime, by the end of June. When it does, we must insist that it reinstates its original ambition to adopt an LGS policy and designate LGS sites.

    A copy of this article is available here: Losing our Local Green Space designation – 16 June 2026

    Here are Bristol Parks Forum’s representations: Bristol Parks Forum response to Bristol Local Plan EXA064: Schedule of main modifications 11 June 2026

    Cotham School and the Stoke Lodge trees

    In its Information Statement of October 2025 concerning its recent fencing works at Stoke Lodge Playing Fields, Cotham School has chosen to misunderstand our concerns about the welfare of the trees at Stoke Lodge Playing Fields.

    The Information Statement includes the following:

    ‘In planning the work to reinstate the fence, the School wanted to respond to feedback, to improve safety by removing muddy paths, to respond to the Bristol Tree Forum concerns regarding footpaths impacting on the roots of trees protected by Tree Preservation Orders, to reduce any other ecological impact and to create an enhanced local open space.’

    Our complaints about the detrimental impact caused by the school’s original fencing layout on all the trees – not just the trees protected by Tree Preservation Orders (TPOs) – growing around the boundary of the site and on the playing fields were made in February 2020, nearly six years ago, in this blog: The trees at Stoke Lodge Park and Playing Fields – a letter to the Council. Cotham School has ignored these complaints and has never approached us to discuss our concerns.

    Furthermore, Cotham School’s decision to drive its new fencing through the root zones of several TPO trees, one of which is a veteran boundary oak, and to destroy other trees, some of which are protected by a TPO, makes it clear to us that the school continues to ignore the welfare of the trees growing at Stoke Lodge.

    We have reported these most recent breaches of TPO legislation to the Local Planning Authority. We have also made clear to Bristol City Council our concerns about the welfare of the Stoke Lodge trees generally. We have been ignored.

    As a result of this neglect, the long-term welfare of all the trees growing on and around the playing fields is at risk.

    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.

    Analysing the Armada Way Biodiversity Net Gain Assessment

    Our Friends at Straw (https://strawplymouth.com/), have been fighting hard to save the few remaining trees on Armada Way, Plymouth so we decided we would try to understand the true impact of the soon-to-be-obligatory Biodiversity Net Gain requirements – how they have been used compared with how they ought to be used – so that the trees that still grow there are properly valued and the loss of their companions can be compensated.

    Our conclusion? Over 1,300 extra new trees will need to be planted to replace what has been lost and achieve the 20% net gain promised by the Council.

    We have been looking in detail at the Armada Way Biodiversity Net Gain assessment report and calculations, which were provided as part of Plymouth City Council’s ‘Meaningful Community Engagement’. We referred to the Biodiversity Net Gain Metric 3.1 User Guide and additional guidance. This document details our thoughts on the assessment. In summary, we believe the assessment has several flaws that led to the baseline (existing) habitat being undervalued. We also found there was a major flaw in the Metric itself, which led to a significant overestimation of new tree (post-intervention) habitat area. The new Metric (4.0), which supersedes the one used in this assessment, has rectified this issue. If the new Metric were to be used, well over 1000 new trees would need to be planted on site to compensate for losses of healthy, mature trees and achieve the required Biodiversity Net Gain.

    Background to Biodiversity Net Gain

    Plymouth City Council (PCC) along with many other local authorities, were early adopters of Biodiversity Net Gain (BNG), which is due to become mandatory in November 2023 as part of the Environment Act 2021. While planning permission for nearly all new developments will require a biodiversity increase of 10% or more, Plymouth City Council have decided that they will require at least 20% BNG for this scheme.

    The BNG Assessment for the Armada Way development claimed that a 25.09% BNG would be delivered on site. Biodiversity Metric 3.1 was used for the assessment, which was undertaken by the Environment Partnership (TEP) using YGS tree survey data; with baseline habitat ‘walkover survey’ data provided by a local ecologist. The Biodiversity Metric is a tool used by ecologists to measure changes in biodiversity on a development site. Biodiversity Metric

    3.1 has now been superseded by Biodiversity Metric 4.0, which was released on 24 March 2023 (more on this later).

    In a BNG Assessment, the biodiversity value of a development site, pre and post ‘intervention’, is measured. Post-development biodiversity value can be increased through the enhancement of baseline habitats and/or the creation of new ones either on or offsite.

    Biodiversity value is calculated in Habitat Units (HUs). These are derived from the habitat area, the habitat’s ‘distinctiveness’ and its condition, as well as any ‘strategic significance’ applicable to the site of the habitat. The time taken to achieve the target condition of newly created habitats is also taken into account, as well as the difficulty involved in creating the habitat. A 30-year maintenance and monitoring plan must be included to ensure newly created habitats will survive and reach the desired condition within the period.

    Requests from STRAW for further information and evidence

    STRAW tell us that they had several concerns and queries regarding the Armada Way BNG Assessment so wrote to the assessor asking for clarification on several points. They also wrote to the ecologist who carried out the baseline habitat walkover survey. Despite a follow-up email, they never received a reply from the assessor. The Armada Way development project manager at PCC, assured STRAW and Plymouth Tree Partnership that the BNG Assessment had been ‘triple checked’ and peer-reviewed and promised that the peer review would be shared. Despite repeated requests, this information was never shared.

    Concerns about the Armada Way assessment

    Significant overestimation of post-intervention habitat area

    One of STRAW’s main concerns around the BNG Assessment for Armada Way, was the significantly greater habitat area ascribed to post development (new) trees than to the existing trees, due to an issue with the Metric itself. We accept that the PCC’s ecologist followed Metric 3.1 correctly in using actual Root Protection Area (RPA) calculations for the existing trees and in using the ‘Urban Tree Helper’ tool for new trees to be planted. However, the two methods are not comparable. If the existing tree measurements had been put into the Urban Tree Helper tool, instead of a habitat area of 0.67 hectares (ha), they would have had a habitat area of over 3 ha. This significant flaw in Metric 3.1 has now been addressed in Metric 4.0, which now requires existing tree habitat measurements to be entered into the tool as well as post-intervention (new tree) measurements.

    Note: Root protection area (RPA) is used as a proxy for tree habitat area. RPA is calculated using a standard equation provided in BS5837:2012 – Trees in relation to design, demolition and construction. Recommendations, using the ‘diameter at breast height’ (DBH) measurement, where the diameter of the trunk is measured 1.5m above ground.

    Although we believe PCC’s ecologist followed the 3.1 User Guide correctly for habitat area calculations, (i.e. using actual root habitat area for the baseline trees and the Urban Tree Helper tool for new trees) we believe they should have noted the significant flaws in the use of different methods for the baseline and post-intervention calculations, which result in the lowest possible habitat area for baseline trees and a significantly exaggerated habitat area for newly planted ones.

    Issues with use of the Urban Tree Helper tool only for the new trees

    The BNG Urban Tree Helper tool assigns trees to ‘Small’, ‘Medium’ and ‘Large’ categories, according to their DBH. When considering the categories for new trees to be planted, the ‘Small’ category is for trees with a DBH of between 7cm and 30cm after 30 years and the ‘Medium’ category for trees with a DBH of >30 – <=90cm after 30 years. Large category trees are those with a DBH of 90 cm or over.

    The 33 new trees (to be planted) were assessed as reaching the ‘Medium’ category after 30 years. Having consulted tree experts and looked at the available literature, we do not believe that these 33 trees should have been assigned to the Medium category. They should have been assigned to the Small category. What is really interesting is that the Medium category trees – those with a DBH of between >30 and <=90cm – are all given a ‘metric area equivalent’ of a tree with a 90cm DBH, so that even a 31 cm DBH tree has the equivalent habitat area of a 90cm DBH tree. This obviously means a significant overestimation in the habitat area for a tree of 31cm DBH. Our researches have found that, if these trees did reach the medium category after 30 years, which is very unlikely, they would only just enter this category – i.e. they would be at the very low end of the range.

    Importantly, an existing tree with a 30cm DBH, using Metric 3.1, would be given a habitat area based on 30cm – 0.0041 ha whereas a newly planted tree – still expected to reach a DBH of 30cm after 30 years, would be assigned a habitat area of 0.0366 ha. This is clearly ridiculous given that they are both the same size trees.

    Using Metric 3.1, if there were 100 existing trees due to be felled, that all had DBHs of 30cm, the total habitat area would be 0.41 ha. If these were to be replaced by 100 trees that were expected to achieve a DBH of 30cm after 30 years, they would be credited with a habitat area of 3.66 ha even though they would probably never grow so large. This demonstrates this important failing of Metric 3.1 and the huge overestimation of the habitat value of newly created tree habitat area as part of the proposed scheme. Fortunately, this has been addressed in Metric 4.0, with the requirement for existing trees also be assessed using the Urban Tree Helper tool – though this is now too late for the Armada Way trees. Metric 4.0 also addresses the issue of newly planted trees being wrongly assigned to the Medium category and thereby achieving a significantly exaggerated habitat area. All new trees must now be assigned to the Small category unless there is strong evidence to support assigning them to higher categories.

    We entered baseline tree data into the Urban Tree Helper tool. The Results show a much higher baseline habitat area (over 3 ha) when following the Metric 4.0 User Guide. Post- intervention habitat area is 1.6 ha; a net loss.

    Other concerns with the BNG assessment

    Not including all existing trees in the baseline calculations

    Apart from this obvious flaw that significantly overestimates new habitat area, we believe the assessment also has several other flaws. There were 11 ‘Category U’ trees that should have been included in the baseline habitat area calculations but were left out. These are trees that were considered unsuitable for retention under BS5837:2012. They should however, according to the Metric 3.1 User Guide, have been included in the baseline calculations. This would have given a greater total habitat area for the baseline urban trees on the site.

    Trees growing in groups were also disregarded and counted as just one tree. Had they all been assessed then this would also have increased the baseline habitat area (as detailed in Section 7 of User Guide 3.1).

    Misleading statements on damage to the built environment

    The BNG assessment stated that ‘the current tree stock is understood to be generally inappropriate to their urban setting, with several causing damage to the built environment’. No evidence was referenced to underpin this statement in relation to Armada Way, and it is not relevant to a BNG Assessment save for assessing their condition. The assessor appears to have used data from a larger tree survey of the area (487 trees), not just Armada Way, and there seems to be no clear evidence in the reports that damage had occurred in Armada Way from the existing (now mostly destroyed) tree stock.

    Strategic significance

    The BNG Metric includes a consideration of ‘strategic significance’ where local plans and strategies are taken into account. We believe there is room for doubt over the strategic significance being set as ‘low’. The Plymouth and South Devon Joint Local Plan, the Plymouth Plan for Trees and the Plymouth Policy Area Open Space Assessment were possibly relevant and if included might have justified setting the baseline ‘strategic significance’ at ‘medium’ or ‘high’. The Plymouth and South Devon Joint Local Plan refers to the mitigation hierarchy: ‘AVOID LOSS – retain suitable existing arboricultural features on site wherever possible’. DEV26.5 in the plan states that ‘applying Biodiversity Net Gain is not an alternative to the application of the mitigation hierarchy and it would be unacceptable practice for a developer to compensate without first seeking to avoid and mitigate’. Whether or not this should have been considered under ‘strategic significance’, it should have been an important consideration for the project. There appears to be no evidence of any attempt, at any stage of the design process, to retain existing healthy, mature trees.

    The Plymouth Plan for Trees (2018) also does not appear to have been considered. The following principles should arguably have been taken into consideration:

    • Plymouth’s trees and woods should be celebrated. Arguably an urban forest in the heart of the city, which happens to be a designated public green space and in a ward with well below average tree cover, should have been valued and celebrated and included in the design from the early stages. Tree canopy cover in the St Peter and the Waterfront ward is 9.3% (forestresearch.gov.uk). The national average for council wards is 16%. The minimum council wards should aim for is 20% (Woodland Trust, 2023). New trees, even if greater in number, would have a much-reduced canopy cover, even in the longer term.
    • Use all available planning and forestry legislation and powers to safeguard Plymouth’s trees. It would be expected that the Plymouth and South Devon Joint Local Plan (adopted in 2019) would have informed the process, particularly: ‘AVOID LOSS – retain suitable existing arboricultural features on-site where-ever possible’.
    • Increase overall canopy cover in the city. The Armada Way proposal appears to reduce canopy cover, despite tree numbers increasing. Tree canopy cover in the St Peter and the Waterfront ward (that Armada Way lies within) is 9.3% (forestresearch.gov.uk). The national average for council wards is 16%. The minimum council wards should aim for is 20% (Woodland Trust 2023).

    The Plymouth Policy Area Open Space Assessment identified Armada Way as a Green Corridor. This does not seem to have been considered and could potentially have increased the ‘strategic significance’ score in the BNG assessment. If these plans and strategies were considered and ruled out as having ‘strategic significance’, the reasoning should have been explained in the assessment, or at least provided upon request, to meet BNG transparency principles.

    Habitat condition

    There may also have been an undervaluation of the condition of tree habitat and ‘other habitats’ in the assessment. The lichen, bryophyte and other epiphyte communities associated with the existing trees (now gone) does not seem to have been adequately considered. There is the potential for bat roosts, and we have photographs of bryophytes, lichen communities and fungi associated with the trees. There were also a number of nests in the trees that were felled (not active ones, but evidence of the suitability of the trees for nesting). These factors form part of the condition assessment of Urban trees.

    The condition of grass habitats and hedge features were set to low, even though they had recently been significantly cut back, and according to the User Guide, they should have been given higher scores as a precautionary measure if recently altered/ cut back. We noted at least 10 different plant species making up the grass habitats, possibly over 15 species. If these had been considered, as they should have been, the condition score would have been higher. When we queried this with the ecologist who undertook the habitat walkover survey, they said they visited the site for an hour to look at the grassland which had just been mown and that he was not involved in the BNG assessment. We also understand that the survey was also carried out during the intense heatwave of 2022.

    Lack of maintenance budget

    It should be noted that the stated BNG (25.09%), which we believe we have shown here to be incorrect, was to be achieved after 30 years. No maintenance budget had been identified beyond the project construction period (approx. 2 years). Further maintenance funding was to be sought from future (unknown) levies on residential development projects, i.e. funding for 28 years of maintenance had not been secured. With the significant uncertainties over changing climatic conditions over this period, and temperature increases highly likely, we would expect a low confidence in survival potential of newly planted trees. This does not comply with the new provisions of the Environment Act 2021 which require that post intervention habitats be maintained for at least 30 years.

    From our detailed analysis, we have advised STRAW that if PCC used the same baseline data for urban tree habitat with the baseline urban tree habitat updated to 3.1137 hectares, which is the area calculated using Metric 4.0, PCC would need to plant at least 1,384 ‘Small’ category trees to achieve at least the 20% net gain promised. On this basis, we calculate that the plans as detailed in the TEP BNG assessment will instead deliver a 62.10% net loss of habitat.

    Here is a copy of our BNG 4.0 calculation.

    Here is a copy of our Urban tree habitat area calculation.

    Conclusions and recommendations

    We conclude that, ignoring the other issues identified above, even if PCC’s calculations were compliant with the Metric 3.1 User Guide, the information detailed here highlights the actual losses on the ground. These losses should be of concern to PCC and should be communicated to the public. It is too late to amend the plan to include the 110 healthy mature trees that have now been felled. The remaining trees could however be included. Significantly more trees would need to be planted to compensate for these losses than the number currently proposed, and even more to achieve the 20% biodiversity net gain aspired to. We believe that both the assessment and the methodology were flawed and that this is an important case study that should inform other projects.

    In our view, it would be prudent now for PCC to undertake a new BNG assessment (particularly as plans have since been amended and most of the trees surveyed have now been felled) using Metric 4.0 and to publicly share the findings, especially given the previous lack of transparency on the ecological assessments.

    We sincerely hope that they will do this and meet their obligation to make good the losses which Plymouth has suffered.