The anger and outrage that erupt when developers cut down urban trees reveals how highly we value them, but difficulties arise when quantifying their worth
Report by Jo Caird
That apple tree in your garden – how much is it worth to you? What about the one in the park that your children like to climb? Or the one outside your house that you have to be careful not to park beneath because your car will end up covered in bird droppings?
It isn’t easy to put a value on nature. Yet that’s exactly what the Forestry Commission has done, publishing, in December 2022, a report that estimated the total economic value of our non-woodland trees – defined as those standing alone or in small groups in urban and rural environments – to be between £1.39 billion and £3.83 billion a year.
Covering about 750,000 hectares, non-woodland trees make up around 20 per cent of the total canopy cover in the UK. For comparison, the new report follows one from 2018 that valued woodland trees at around £4.9 billion per year. These figures (which cover such a broad range because they represent two different methodologies) quantify the so-called ‘ecosystem services’ provided by these trees, or the direct and indirect contributions that we gain from them. These include carbon storage and sequestration, removal of air pollution, temperature regulation, noise reduction and flood mitigation. The report also provides a total amenity value – essentially a replacement-cost estimate – for all urban non-woodland trees of £429 billion.
These are striking numbers, but how useful are they when it comes to shaping our attitudes to, and therefore our protection of, this most precious of natural resources? Should we not just be able to appreciate and value our trees without reducing them with this crudest of indicators? Jon Stokes, director of trees, science and research at the Tree Council, a charity that works to create and promote diverse treescapes across the UK, acknowledges the challenges inherent in placing an economic value on trees. ‘Whatever you’re measuring is, by default, only a fraction of the things that the tree might deliver,’ he says. ‘How do you quantify the value that a person places upon that magnificent tree at the bottom of their street that makes them feel happy when they get up in the morning because they see leaves and colour and wildlife?’
The report is explicit about the benefits of trees that it doesn’t cover: their ‘social and cultural values’, ‘few [of which] have been monetised’. Future valuations, it suggests, ‘should seek to expand non-woodland tree valuation estimates through a more comprehensive consideration of the range of benefits that these trees are credited to provide to society’.
All that aside, Stokes says, the current figures are useful in enabling comparisons to be made with the value of woodlands. We may, he says, ‘start to realise
that all of these other treescapes are an important part of our landscape, of our culture, of our history, and therefore are worth investment. That enables us to deliver positive benefits for people wherever in the country they happen to be.’
The focus on urban trees is important not only because of their particular benefits in urban environments – around reducing what’s known as the urban heat island effect through providing shade and evapotranspiration, for example – but also because these are the trees that most people encounter in their daily lives (in 2019, 83 per cent of England’s population lived in urban areas). ‘Part of Tree Council’s mission is to try to rebalance the scales a bit and to draw more funding into things that are where people are, where people value the trees, where people see the trees,’ explains Stokes.
‘Part of the conversation has always been about, how do we get all these other treescapes to matter to as many people as possible?’ he continues. ‘To make sure that we realise that we shouldn’t just be planting forestry, we should be planting trees where everybody else may see them and where they may value them – forget the economics – for themselves.’
Understanding and appreciation of the value of non-woodland trees has been gaining momentum over the past four or five years, says Stokes (he credits Michael Gove’s post-Brexit articulation of ‘public money for public goods’ as a turning point), but data thus far have been sparse and localised. This recent report by the Forestry Commission will be helpful in moving the conversation forward because of its national focus.
Professor Giuseppe Scarscia-Mugnozza, head of the BioCities Facility at the European Forest Institute, which conducts research and provides policy support related to forests globally, argues that ‘this type of analysis is fundamental to being able to balance the costs [of urban trees] with the benefits that generally outweigh those costs’.
He adds that this is crucial for both justifying public spending and attracting private investment. ‘We need public–private partnership because public money is important but cannot cover all the expenses,’ he explains. ‘There is a lot of potential for private investment and the money, quite frequently, is there. What is lacking is a clear cost–benefit analysis – information on the possible return on investment.’
Having the figures to hand is certainly helpful when it comes to making the argument for green infrastructure, including urban trees, says Caroline Woodley, the London Borough of Hackney’s cabinet member for family, parks and leisure. Over recent years, following its declaration of a climate emergency in 2019, the council has delivered a tree-planting programme that includes 5,000 new street trees. That programme, which cost around £3.4 million, prioritised streets without existing canopy cover and those where planting could be done relatively simply, without having to navigate utilities or other street furniture. The next stage of the plan is to take space away from vehicles in some streets to give to green infrastructure, which will be far more challenging.
‘To take that [ambition] forward now, we’d have to build out and that will bring in a new level of cost,’ Woodley says. Being able to present figures on the cooling, carbon-storing or air-pollution-removing potential of urban trees ‘will help us to justify doing that build-out work to create new infrastructure on the roads, divert traffic, de-pave, put in sustainable urban-drainage systems and go that next step’.
Being able to point to trees’ economic value has other benefits for policymakers. ‘It helps us make better, more informed decisions or it prevents us making rash decisions to lose things of higher value,’ says Darren Sharpe, natural and historic environment manager at Peterborough City Council.
This is particularly relevant when it comes to making the case for retaining trees threatened by development. ‘We need to be able to differentiate between the higher-yielding tree resource and the lower-yielding tree resource then pick our battle according to its value,’ Sharpe explains. ‘There will be certain things that we will maybe have to compromise on and let some of the lower-value stuff go sometimes, but knowing that the higher-value ones are the ones where we’re going to dig in and fight to keep, because that has the biggest yield, financially, environmentally.’
Knowing the value of what’s there is also essential for securing suitable compensation from developers for trees lost, although Sharpe stresses that, ‘mitigation is not the ideal; the starting point is always wanting to retain what’s already there’.
The tension between enabling urban development – for housing, transport, commerce or whatever else – and maintaining existing green infrastructure is being felt very palpably at the moment, thanks to recent furores over the felling by developers of much-loved trees in Wellingborough, Plymouth and St Albans. For barrister and climate activist Paul Powlesland, who last February found himself climbing an ancient lime tree in Wellingborough to prevent its felling to make way for a dual carriageway, ‘trees have an intangible value. But it does help to show that what is seen as a stack of wood by some councillors is actually a very valuable thing and, to some extent, irreplaceable.’
Recognising the value of particular trees is one thing; guaranteeing protection for that tree is another. Powlesland points out that the lime trees felled in Wellingborough earlier this year had tree preservation orders (TPO) on them, so should have been safe. That development, including any further tree felling, is now currently on hold ‘to enable wider community engagement’, with a spokesperson for North Northamptonshire Council pointing out that leadership of the local authority has changed hands since the planning application was granted. However, it highlights the fact that a local authority can simply remove a TPO if an exemption is deemed to apply.
‘One of the big problems with tree protection in this country is that we often have the fox guarding the hen house,’ Powlesland says. ‘So councils, who are often the ones who want to chop trees down [to enable development] are those who are supposed to protect them. And even when the council doesn’t want to chop them down, we don’t have an independent voice advocating for trees.’
The data bear out this view. Out of 59 UK cities included in a 2020 OECD report on urban-tree loss, all but ten (80 per cent) showed a decline in tree cover between 1992 and 2018. That compares to a decline of 50 per cent in all OECD cities, and 72 per cent of OECD cities with a population of at least one million people.
There’s clearly a lot of work to do here but the situation may not be as dire as it seems. Stokes, of the Tree Council, is optimistic that there has been a policy shift in the past five years that isn’t yet reflected in the data on urban tree coverage. ‘It feels that something has changed and people are starting to see that value,’ he claims. ‘But quantifying that is currently very difficult. There is definitely an element of hope in that thought process, as well as reality. But in the absence of data, which we don’t have because of the timescale, I have to go with hope.’
He points to local authorities’ enthusiastic uptake of the various pots of central-government funding now available for non-woodland tree-planting schemes as evidence of this shift – including the Local Authority Treescapes Fund (LATF), which launched in 2021 and saw 139 local authorities share £4.4 million, and is now in its third round. ‘There is a huge wish to take up the offer in this space and that’s because we’ve been economically starved of money for those trees,’ he says. ‘Some of those spaces that have lost trees now have the opportunity to put them back, which they haven’t had for a very long time.’
One of the local authorities taking up that offer is North Northamptonshire. It has received, among other funding, £497,184 from the LATF and £150,000 from the Woodland Creation Accelerator Fund (which, confusingly, also covers non-woodland trees) to fund two new roles that will help fulfil the council’s ambition to restore canopy cover in the area historically covered by Rockingham Forest. For Liam Faulkner, who, as grounds services manager at the council is responsible for street tree planting, the economic value of non-woodland trees has little bearing on how they’re perceived by the public:
‘There’s already an understanding. Over the last five to ten years, people have definitely come to appreciate the benefits of nature,’ he says. ‘Trees impact on our mood and emotions, our psychological wellbeing, but the impact of that can be immeasurable. Through the pandemic, people became reconnected with their local green spaces. People have this real sense of ownership.’
That engagement is feeding through to local businesses and developers, Faulkner says, who are responding to increased demand for green infrastructure with better provision than in the past. ‘Corporations really want to not just tell people that they’re doing the right thing, but show them as well,’ he says.
While appreciation for green spaces surged as a result of the pandemic (44 per cent of respondents to a 2021 poll by Natural England said visiting green and natural spaces had been more important to their wellbeing since coronavirus restrictions began) not everyone is enamoured of urban trees. Peterborough City Council’s Darren Sharpe has seen the same shift in attitudes as that described by Faulkner, but adds that ‘there are people who see trees as untidy and unclean and unpleasant’.
Hackney Council tree officers have also encountered negative attitudes to street trees among some residents, but have found that people usually come around if time is taken to discuss their concerns. ‘You get into a conversation with people about the types of trees that we’re planting, that these trees will be correct for the location, they won’t get too big, they’re not going to cause problems like some of the species that were planted by the Victorians and Edwardians,’ says aboricultural officer Raffe Ross-Pearce. ‘You explain that this is going to have lovely flowers in spring and in autumn it’s going to have a beautiful red hue, and bees are going to love it. People start to see why you’re doing it and by the end of the conversation, normally they’re quite happy.’
That’s important because buy-in from the public is going to be crucial to the success of the urban tree-planting schemes taking place up and down the UK right now and in years to come, both in terms of community planting sessions within green spaces and supporting local-authority tree-maintenance schemes with watering as the climate crisis bites.
As Stokes says: ‘It is vital that we engage the community in the journey. We say to local authorities that it has to be not just a strategy for the trees that you own and manage – it needs to be a strategy for the wider treescape around you that involves the community, that involves the businesses, that starts to think more holistically than we have done.’
Ultimately, then, the economic-value argument is just one of the tools in the arsenal. ‘It’s sad to think that you have to commodify [trees],’ Stokes says. ‘Anything that gives articulation to the fact that trees matter, any evidence that we can compile that proves that they have value, and any way that that can be articulated to the right people in the right way, all of that is a good thing. No one tree is going to make a global difference per se, but every single tree collectively does.’
