9 minute read
Building the urban forest
Retrofitting the urban forest into social housing landscapes brings significant benefits, especially when residents are engaged in decision-making and delivery.
In the current climate emergency, retrofit is an increasing remit of landscape practice. This is of particular relevance in urban spaces, but is also applicable to multiple landscape interventions. Trees and other green infrastructure play a critical role by providing multiple benefits and ecosystem services.
Retrofit projects are needed where the scope of works is limited to interventions installed within an already determined landscape or built infrastructure. In cities where open space is at a premium, available land often lies in deprived areas and is surplus to requirements. These landscapes have multiple stakeholders, all with different needs and priorities, from landowners to neighbouring residents.
The ‘urban forest’ refers to all trees planted within towns and cities and is defined by Forest Research as ‘… the whole population of trees and woodlands in urban areas – whether owned by private landowners, institutions or local authorities.’
Urban forest trees may be planted independently of each other, in woodland groups, small, fractured clusters, along streets, transport and linear features such as rivers in parks, open spaces, and private gardens.
Trees for Cities operates in UK towns and cities delivering volunteer and community-led tree planting; targeted on areas of highest social and environmental deprivation. This approach is supported by evidence of a direct correlation between areas deficient in tree canopy cover and areas of social and environmental deprivation. These landscapes and their communities demonstrate underinvestment and stress. Tree planting costs significantly less than what might be needed to bring the hard infrastructure of an entire project up to the standards found in more affluent areas, where investment and resources are plentiful. However the impact and benefits gained from the ecosystem services of trees is significant.
Tree canopy cover refers to ‘the area of ground directly covered by leaves and branches of a tree and is expressed as a percentage’ (Forest Research, 2017). This measurement does not capture tree health, vigour, or species mix, but urban tree canopy cover data is widely used to inform effective tree strategies, management plans and planting targets by identifying areas in greatest need of more trees.
Being aware of landscape-scale tree canopy cover can support equitable proposals at site level and beyond boundaries. This is applicable for new development and retrofit delivery. A simple way of focusing on the interaction of social and physical projects at landscape scale is Cecil Konijnendijk’s 3 - 30 -300 theory,⁶which has gained traction as a highlevel means to engage and target greater areas of urban tree cover. Setting the target at an ambitious minimum 30% tree canopy cover (Defra’s current ambition is 16.5% across England), this simple ask is that everyone can see at least three trees from their windows, live in a community with 30% tree canopy cover and walk 300 metres to a green space. This focus on trees and people recognises the urban forest as an interconnected, planned ecosystem that can meet environmental, spatial, social and health and wellbeing needs.
Twentieth-century housing estates can deliver retrofit tree canopy cover and support environmental and social equity. Estates are an ideal location to embed the multiple benefits of the urban forest, particularly where tree planting has reached the end of its natural life or where it did not form part of the original master plan. Many 20thcentury housing estates utilised trees as a critical part of their infrastructure; however, many did not. Dave Yates describes how former GLA architect, Michael Brown, embedded the integration of trees in his 20th-century estates and revisits the 45-year-old Beavers Farm Estate in West London. He states, ‘Brown’s vision of this estate is held in the canopies of the tallest – they reach out over the estate, touching each other and the very roofs of the tallest blocks – they join to form a roof, a cover that protects, insulates and isolates the estate from noise, from concrete and from misery.’
Racecourse Estate, Northolt
Seven miles north of the Beaver Estate, the former Northolt pony-racing track was developed by Ealing Council in the 1950s into what is known today as the Racecourse Estate. This estate hosted tree planting and other greening interventions by Trees for Cities, over a ten year period, culminating in a multi-year pilot project, funded by National Lottery Community Fund and Ealing Council from 2019 to 2023.
Racecourse Estate is spacious with a dispersed community. A Michael Brown scheme with carefully planned legacy trees this is not; instead its layout followed the ready-made infrastructure of the old pony track, its housing stock utilitarian but solid.
Yates continues, ‘The estate which was eventually constructed was by no means a high-density development and made very effective use of open space. Large areas were left unbuilt upon, including the ”backstretch” of the racetrack.’ The site relies on old field boundary trees for mature canopy while the dominant landscape consists of underutilised, species-poor, close-mown amenity grassland dotted with sparsely scattered trees.
The project focused on a clustered social hub of existing facilities: GP practice, schools, shops and social housing all within 500m of each other. Falling within the top 20% deprived wards in London, the top 15% deprived neighbourhoods in Ealing and the top 20% deprived in the country, Racecourse Estate’s green spaces offered potential for positive community impact, if residents could be mobilised and energised.
This became an exercise that sought a cohesive solution to the estate’s low tree canopy cover, one that would visually and physically unite residents with their landscape. In doing so, the team hoped to reconcile the estate’s social ‘disconnectedness with nature’ by enabling a more engaged and self-determining community. The process involved multiple site-based engagement events – walks, talks, drop-in sessions, visits to local schools – leading to annual and frequent tree planting sessions and summer celebration events.
Trees for Cities allocated a dedicated community coordinator to the project, who focused on relationship development with residents to establish a legacy greening group. This was a long-term desire of local people, achieved with support of the Freshwater Foundation. Targets for tree planting and people engaged were achieved through the creation of tree-lined streets, pockets of woodland and new community orchards. Community and volunteer planting events were well attended and new planting was accepted positively by local people, with minimal subsequent vandalism.
The team faced complex community issues that could not be addressed with available resources, stakeholder support and the timeframe. Structural tree planting was successful, but green interventions to courtyards and small social spaces were less so. Despite huge efforts to engage through Covid-19 lockdown, failure to fully capture residents’ strength of feeling meant interventions had to be adjusted after they had been installed. This is reflected in the social impact research, where well-attended tree planting events resulted in a general improved perception by residents of their open space. However long-term interest was not achieved, and microscale social spaces failed to result in impactful positive activity and feedback.
Reporting on ambitious community impact data was difficult, which caused the team to spend time reflecting on what worked well and what did not. These considerations are set out in an honest and positive impact analysis resulting in Critical Success Factors (CSF) which are being shared and followed for future schemes.
Using the Critical Success Factors can support better definition of project scope from the outset to enable improved planning for micro-spatial and social geographies, as well as wider estate landscapes. ‘Understand the social and geographic landscape’ is the most pertinent fit, and captures best the need to address different spatial scales and people’s interactions with them.
Tree planting will not resolve multiple social problems. Planning at large spatial scale will only work by understanding and resourcing solutions at micro scale at the same time. Separating this project into two aligned programmes of structural and microscale projects with separate social and environmental impact targets, might have shown better outcomes for the smaller sites. Focused community engagement activities could be prioritised and given targeted resources for bespoke solutions. Structural tree planting activities could then have been planned across the programme with different impact objectives relating to a larger-scale plan rather than seeking to spread limited funds thinly.
This pilot aimed to ‘develop and test an effective, sustainable and replicable cluster approach model by creating opportunities for everyday interactions with diverse natural spaces for residents across the estate.’
As the impact evaluation indicated, building community cohesion on a diverse social housing estate is complex and takes time, and there are many factors which affect community cohesion that are beyond our control, including crime and anti-social behaviour and the transiency of the population.
Nevertheless, we know that over the final four-year programme, people gained new experiences, knowledge and skills about planting trees from events, and children gained confidence to plant trees. People agreed that the appearance of the estate improved and overall levels of respect for their greenspace increased. The new greening group increases the chances of long-term and positive interaction with estate’s green spaces.
A vast amount of learning has been accrued, providing valuable insight that can be applied in future to deliver more effective community-led projects. The new trees will quietly continue to deliver multiple benefits to the residents of Racecourse Estate in the same way as Michael Brown’s trees continue to do after 50 years thriving on the Beavers Farm Estate.
Suzanne Simmons is Urban Forest Director at Trees for Cities. She is a chartered landscape architect and specialises in planning and delivering urban green infrastructure.
