“Get walkability right and so much of the rest will follow” — Jeff Speck, “Walkable City”, 2012
As city populations grow, urban trees cannot be viewed as a luxury: Trees are an essential component of a livable community and a core strategy for improving public health.
The Nature Conservancy in America has just released its latest report, ‘Funding Trees for Health – An Analysis of Finance and Policy Actions to Enable Tree Planting for Public Health’ and it states that scientific case for the benefits of trees and urban nature has become more solid over the last few decades. The report focuses on the links between trees and public health stating that recent science shows that the link is robust and economically significant. The central question of this report asks: If trees are so important for health, how can cities use innovative finance and policy tools to enable tree planting for public health?
Despite the large literature on the many benefits provided by street trees and other natural features, U.S. cities are experiencing declines in urban forest cover. New tree planting isn’t keeping pace with the mortality of existing trees, either from natural causes or from clearing of trees for new development. If trees provide so many benefits, why are cities letting this natural resource dwindle away?
The report identifies four main barriers preventing cities from fully seizing the power of street trees and other natural features:
The investment gap: How much more investment in trees is needed need to maintain current urban canopy and then significantly expand it to seize greater potential health benefits. The report estimates that an additional investment of around $8 per person annually would be enough to create this green future in US cities. A green urban future is not an impossible dream, but is quite affordable, if policymakers and others decide to make this investment.
The last section of the report describes some specific solutions that can enable tree planting for public health. The solution that will work will vary by city, but what matters is giving value—financial and moral—to the benefits that trees provide to health.
The report discusses some methods commonly used by cities to try to break silos by linking urban forestry to other municipal goals. These can include planning processes such as sustainability or comprehensive plans, heat action planning or planning related to compliance with existing policy such as the Clean Water Act. The report discusses common financial mechanisms for urban forestry, such as funding from public revenues, municipal codes and policies, and partnerships with companies and NGOs. The report suggests a possible way to overcome the funding barrier may be to more closely link the goals and funding of the health sector with the goals and funding of urban forestry agencies. If trees have significant benefits to physical and mental health then why not consider a link between health funding and urban forestry?
The concept of linking finance streams for nature and health seems simple. Those whose mission it is to plant and maintain trees and other urban vegetation spend money and resources to make urban areas greener, which delivers significant benefits for mental health. This helps those in the health sector better achieve their mission of improving people’s health and well-being. To complete the circle, therefore, the health sector (whether public or private institutions) could supply some financial resources that help partially pay for the activities of those in the urban forestry sector.
Sustainable drainage systems (SuDS) could be improved for biodiversity and local people with the help of two new evaluation methods presented by a recent study. The methods, which assess the value of SuDS sites for wildlife habitat, carbon sequestration, recreation and education, are described by the study’s authors as cost-effective, quick and reliable, and could help designers plan and retrofit SuDS that are wildlife-friendly and socially inclusive.
Source: Mak, C., Scholz, M., & James, P. (2016). Sustainable drainage system site assessment method using urban ecosystem services. Urban Ecosystems. DOI:10.1007/s11252-016-0593-6. This study is free to view at: http://link.springer.com/article/10.1007/s11252-016-0593-6.
SuDS mimic nature to manage and treat storm water. There are various forms of SuDS which help prevent flooding and clean up contaminants; these include ponds, green roofs, artificial wetlands and absorbent pavements. The green infrastructure provided by SuDS is seen as an important way of helping EU Member States achieve good surface water status under the Water Framework Directive.
Fig 1. Rural conditions – impacts of urbanisation on a catchment. (Ciria)
In the UK, where this study was conducted, the Construction Industry Research and Information Association (CIRIA) has recently updated its influential SuDS manual (1), which provides guidance on the planning, design, construction, operation and maintenance of SuDS. This latest version promotes the design of SuDS design that provides a range of ecosystem services.
The evaluation methods presented by this study are intended to support this ecosystems-services approach (2). They can help designers understand and improve the value of a SuDS site. They also give designers a better understanding of which features (2) of a SuDS site provide which ecosystem services, to help guide new developments.
The first method considers which features provide biodiversity-related services, specifically habitat for wildlife and carbon sequestration. It is adapted from an existing method (3) and based on evidence that diverse vegetation, at various heights, is best for providing habitat. The method involves assessing which broad types of vegetation are present, such as trees and grasses, at which heights (e.g., upper canopy of a tree, low bush, long grass, cropped grass), and if there are any plants in water.
Designers can then give a SuDS site a score to indicate its potential for providing habitat and carbon ecosystem services. In general, points are given for every layer of vegetation (including aquatic plant species, if present). However, the method considers ecosystem disservices as well as services, and the scoring system deducts points for some layers; for example, cropped grass, which is unbeneficial for carbon sequestration. The presence of any built and impermeable layers at a site (e.g. concrete surface) also leads to points being deducted.
The second method considers which features contribute to recreational and educational ecosystem services. It assesses public accessibility to a site (both legal and physical), evidence of the site being used for educational purposes by community groups, educational signs, the distance to the nearest educational establishment, and recreational infrastructure (e.g. benches and footpaths). Again, ecosystem disservices are considered, so the presence of litter and dog faeces is also assessed, as well as bins, which help reduce these two problems. Each feature is scored on a scale of 0 to 3. Scores for recreational features and scores for educational features are combined separately to produce two total scores.
The researchers tested the two methods on 49 sites in and around the city of Manchester, UK. This revealed that large sites (over 5 500 m2) with permanent aquatic features such as ponds tended to be more capable of providing habitat and carbon sequestration services. Scores for habitat and scores for recreation were positively linked to each other. The researchers acknowledge that there is some subjectivity to the evaluation methods, but say that they provide the right balance of reliability, speed and cost-effectiveness.
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The Moravia Florece Para la Vida project in Medellín, Colombia – an area that used to be a rubbish dump is now the focus of an art corridor and newly formed community garden and public space. The expansion of the corridor of art and memory together with the construction of the second greenhouse are part of the intervention carried out by the Mayor of Medellín in this area of the northwest of the city, which for years was a rubbish dump.
According to Gloria Alzate, Secretary of Environment, “The change in the environment must be accompanied by a social transformation, that is why we have accompanied the families in the transfer to other sites of the city and have strengthened social ties, as well as the creation of productive enterprises has been encouraged “.
The project, according to figures from the Ministry of the Environment, has benefited nearly 40,000 people who live in the neighborhood and its area of influence, since it has allowed the consolidation of small businesses, such as flower crops that are managed by women in the neighborhood. sector.
In the process, which began in 2013, there have been works of urban, landscape and environmental interventions in 35,000 square meters of the 72,000 corresponding to the old garbage dump of the city. In this space they have planted 3,600 square meters with 46 species of ornamental and floral plants.
Among the works carried out is the extension of 265 meters of the Corridor of Art and Memory, composed of 300 linear meters in which the inhabitants portrayed stories, characters and images of the neighborhood.
The construction of the second 1,000-square-meter greenhouse with capacity for 40,000 plants was also completed, as well as the installation of 39 fences with historical photographs of the sector and 14 sculptures by artists from three universities in the city.
“This has been a social and economic process, but also cultural because we change mentalities with art,” said Alzate.
The story begins with internal violence in Medellin during the 1970’s and ‘80s. Conflict involving guerrilla groups, military groups, and drug cartels led to the displacement of a large number of people. Many had been living in impacted rural areas, and moved to Medellin seeking security and the opportunity for a better life. These migrants began to build informal housing at the Moravia garbage dump, which eventually grew into the most densely populated community in Colombia.
Inhabitants survived through the recycling of the waste materials and the close transport links, like the old train station, but continued violence and an economic crisis only exacerbated the influx of migrants and high population density.During this time the sanitation and health standards of El Morro de Moravia were dire. In fact:
In 1983 the dump was moved to prevent the landfill from defining the future development of the area.
By 2006 Mayor Sergio Fajardo and Colombia’s Interior Ministry declared the situation in Morro de Moravia a “public disaster”. A government initiative had begun to transform the community by this time, and the former garbage dump was to be converted into a public space.
First, residents of the dump were evicted and relocated to safe areas, then they began the process of decontaminating the mountain and converting into public gardens. Next came a series of small urban projects, new dwellings, and the opening of an educational and cultural building.
All projects employ residents of the neighborhood, so the transformation can be the pride of those who live there. One stand-out project was a series of greenhouses atop the old garbage hill that employed single mothers from the community.
The goal for the project is “Moravia florece para la vida”, or that Moravia should “blossom into life”. The result of government projects and work by locals seems to indicate that Moravia is indeed blossoming, quite literally. Today, locals have planted more than 50,000 plants of 47 species.
The London Assembly’s latest report, ‘At Home with Nature: Encouraging biodiversity in new housing developments’ published in Jan 2017, delivers the latest findings from the Housing Committee which scrutinises the Mayor’s role and record in delivering the private, social and affordable homes London needs.
There is a risk that London will see its biodiversity being squeezed or reduced as planners and developers try to increase housing density in the city. Nature provides physical, mental, social, environmental and economic benefits for city dwellers, but both flora and fauna are rapidly decreasing in UK cities. The Mayor has an important role in ensuring biodiversity is enhanced and new habitats are created, as London attempts to tackle the housing crisis.
Biodiversity is part of national, regional and local planning policies. Collectively, these policies provide a good overall strategic vision for providing for nature in London. Unfortunately, these policies are not always translated at ground level.
Some European cities explicitly recognise the importance of green infrastructure and the environmental, social and economic benefits it provides. Several cities have introduced a planning tool called a ‘green factor’ or ‘green space factor’ (GSF) to ensure a minimum level of greenery in new developments. This planning tool has increased levels of green space and improved resilience to flooding and climate change impacts in these cities.
There are inconsistences at borough level when it comes to approving planning applications. This is due to lack of ecology expertise within planning departments and other pressures, for example housing target pressures, which can impact on the decisions of the authority. Funding cuts have reduced the capacity of planning departments.
Developers are sometimes uncertain of the steps needed to promote biodiversity and therefore the cost of doing so. The historic emphasis on protecting key species sometimes worries developers and mean some avoid biodiversity entirely. However, some developers clearly do value biodiversity on their sites and include biodiversity adaptations and green infrastructure where it is feasible. The inclusion of biodiversity and green infrastructure in a site has been shown to increase the chances of receiving planning permission with fewer conditions, positively affecting prices paid and speeding up the rate of sales.
This report explores the current situation and offers some potential solutions to ensure that London maintains and improves on its current levels of biodiversity, as it continues to grow and change.
London is still one of the greenest cities in the world but, in the rush to tackle the housing crisis, there is a risk that opportunities to protect and enhance local flora and fauna are being lost. In order to build the homes that London needs, a large proportion of these homes will be built on brownfield land and at higher densities. An increased housing density could lead to a more fragmented environment for nature, reducing biodiversity and access to nature for Londoners.
Although nature provides physical, mental, social, environmental and economic benefits for urban dwellers, both flora and fauna are rapidly decreasing in UK cities. The 2016 State of Nature report showed that, in the UK, 56 per cent of species are in decline and 7 per cent of urban species are threatened with extinction. For example, London’s hedgehog population has dropped by 50 per cent since 2000. This is a further concern for London government as nature can also improve the city’s resilience to climate change and can help mitigate issues associated with high density living, such as flooding and the urban heat island effect, thereby generating financial savings in the long term.
The Mayor has an important role in ensuring biodiversity is enhanced and new habitats are created. A large proportion of new homes will be built on public land and will be subject to Mayoral planning approval if they are of potential strategic importance to London. This means that the Mayor can, and should, push for higher requirements for biodiversity on these sites in order for planning permission to be granted.
Restoration of the Mayes Brook in Mayesbrook Park, in the London Borough of Barking and Dagenham, was an opportunity to create an ecological and community focal point within a broader environmental regeneration project. It was designed to produce the UK’s first climate change adaptation public park. This restoration of an urban river within a barren park landscape is a good example of an approach that combines flood storage, biodiversity enhancement and adaptation to climate change within a city environment. This study explores some of the key benefits of the planned river restoration and the wider park ‘greenspace’ improvements, in terms of their impact on ecosystem services. The urban setting means that restoration and improvements contribute to ‘regulatory services’ (regulation of air and water quality, microclimate and flood risk) affecting the local community. Enhanced recreation and tourism (cultural services) are also likely to bring benefits, since many people in the borough lack gardens or ready access to other green spaces.
Robert Oates, Executive Director of the Thames River Restoration Trust introduces a field visit. Source: Ecosystems Knowledge Network
The benefits for ‘supporting services’, which are hard to quantify but important in maintaining ecosystem functions, are significant in terms of nutrient cycling and providing habitats for wildlife. This latter ensures there are animals and plants capable of colonising the wider landscape as the habitat improves. These improved habitats also serve as ‘stepping stones’ for wildlife to move across and between limited and fragmented suitable habitat in the urban landscape. Due to the urban setting and lack of biodiversity in Mayesbrook Park and the Mayes Brook, restoring the river does not boost ‘provisioning services’ (things that can be taken from ecosystems to support human needs, such as fresh water, food, fibre and fuel, and so forth). Many of the more important benefits of the Mayesbrook Park restoration can be seen in social and health aspects, enhancing the quality of life in the borough and the wellbeing of local communities.
In fact, if the annual value of services to health, risk and culture are pooled, despite there remaining many unmeasured or possibly unquantifiable benefits, they will account for over 90% of the total annual ecosystem service benefits for the Mayesbrook Park restoration scheme. The overall benefits are substantial relative to the investment. The lifetime value of restoring the site across the four ecosystem service categories (provisioning, regulatory, cultural and supporting) yields a grand total of calculated benefits of around £27 million, even if ‘likely significant positive benefits’ for the regulation of air quality and microclimate are excluded. This is compared to the estimated costs of the whole Mayesbrook Park restoration scheme at £3.8 million including the river restoration works. This produces an excellent lifetime benefit-to-cost ratio of £7 of benefits for every £1 invested. Urban river restoration would therefore be of major public value, fully justifying the planned investment and providing firm evidence that investment in urban ‘green infrastructure’ is highly favourable for the health and wellbeing of local people and the economic improvement of deprived wards. Restoring the vitality and function of the natural environment tends to enhance or maintain benefits across all ecosystem service categories. This contrasts with traditional single element solutions, which tend to maximise only the targeted services and often are associated with unintended consequences for other interconnected services. The case for the application of ecosystem-based solutions to environmental management problems is thus substantiated.
View of one of the lakes to be restored. Source: Thames Rivers Trust
The study sets out a range of options for further enhancing public value from
the restoration scheme, through new or redesigned initiatives or in management
practices. These include:
Assessing the ecosystem service implications for all of these options, and others that may be identified in later phases of planning and research, would help to support the economic case for their implementation. This case study provides evidence to help improve the current scheme design and the greater integration of social, economic and ecological benefits in future initiatives. The results of this assessment are valuable not only in the Mayesbrook Park restoration project but are also applicable to wider urban river and urban area restoration initiatives and will support future research in this field. It will also help in achieving ‘good ecological potential’ for the Seven Kings water body as part of the Water Framework Directive.
Restoration of the Mayes Brook – Executive summary – full text
What is this initiative about?
This project illustrates how an assessment on the services that nature provides for people helped in the regeneration of Mayesbrook Park. The transformation allows the park to better serve the local community and also the city of London under a changing climate with increased flood risks.
The park is in the Borough of Barking and Dagenham, one of the twenty most deprived boroughs in the UK. It was previously under-used and had few amenities, whilst the river was confined to a concrete channel and lay behind a metal fence, providing little value to wildlife or people.
How does it reflect the ecosystem approach?
An assessment of the ecosystem services provided by the park both now and in the future identified its role in reducing flood risk, as well as its value for recreation and wildlife. The assessment illustrated that £7 of benefits will be provided for every £1 invested in restoration of the park, which provided the basis for a funding partnership worth £1.6 million.
In valuing the ecosystem services, the project reflects the ecosystem approach, in that “Conservation of ecosystem structure and functioning, in order to maintain ecosystem services, should be a priority target of the ecosystem approach”. The project also considers the long term effects of climate change and the associated risk of increased flooding and increased summer temperatures. As such it reflects the ecosystem approach, which states “consider mitigating actions to cope with long-term changes such as climate change”.
Progress so far
The first phase of the project includes re-routing the Mayes Brook along a more natural course, renewing the disused lakes and planting trees. The second phase includes the restoration of the two lakes, one for boating and one for angling, which will also improve habitat conditions for wildlife. A visitor and facility centre will be built, along with a café and permanent exhibition on what the park is doing to adapt to climate change.
Challenges and lessons learned
The project highlights how an economic appraisal of the benefits that an area of land can provide for people, can bring about significant change. The clear demonstration of the value of the project helped reassure and engage representatives of the local community.
It is also an example of partnership working, and of a scale of park regeneration that was only made possible by the combination of staff, funding and technical resources provided by the various partners involved. It illustrates the potential for such a project to cause a resurgence of public interest in nature and access to the outdoors. The involvement of the Environment Agency as a partner helped in the process of securing the numerous approvals needed (flood risk, contaminated land, soil disposal etc.).
“Get walkability right and so much of the rest will follow” — Jeff Speck, “Walkable City”, 2012
Allies and Morrison’s proposal is based on reimagining the existing infrastructure of James Cubitt’s 1869 designed Blackfriars Bridge by using spare capacity to accommodate a through public garden of similar size of the proposed Garden Bridge, while still providing the vital north-south link for vehicular and cycle traffic along the Blackfriars Rd – Farringdon Rd axis. The Allies and Morrison team state, “By consolidating both the east and west pavements into one larger 14m wide pavement on the west side, we could create a brilliant pedestrianised garden.”
This alternative design would still offer dramatic views of St Paul’s and the City to the east and Westminster to the west and offers a positive response to the Mayor for London’s recent publication Public London: Creating the best public realm – authored by Peter Murray, Fred Manson and Pam Alexander. The Mayor’s ambitions for the creation of new public spaces and places in London are to, “bring public transport, walking and cycling together to create high quality public realm.”
Using the existing Blackfriars infrastructure connects the north and south shores of the Thames using existing infrastructure thus providing increased capacity in pedestrian access between The City to the north and Southwark and Elephant and Castle to the south whilst creating a green space for commuters plus additional green infrastructure capacity for London. The provision of additional pedestrian space also links with the latest ‘Cities Alive’ report, a collaboration between Arup’s Foresight + Research + Innovation, Transport Consulting and Urban Design teams. The report ‘Cities Alive: Towards a walking world’ discusses the benefits of walkable cities – economic, social, environmental and political – and sets out measures for improving walkability. “Creating safe and efficient transportation systems, liveable environments, a sense of place and community, and smart and responsive cities will all help to make walking a normal part of everyday life and the natural choice for shorter journeys.”
This Blackfriars Bridge Garden concept celebrates existing infrastructure heritage just like New York’s Highline Parkway . Allies and Morrison claims that their proposal does not require extensive construction and can be delivered minus the initial cost of construction of a new bridge whilst connecting two areas of London where there is an existing need for additional commuter capacity. “It would provide 40,000 sq ft of new green space. It would remain public and accessible to all, seamlessly integrated into the existing public realm on both sides of the River without obstructing any of its views of St Paul’s. This light touch approach would be carbon neutral, and together with the cycle superhighway and solar panelled roof of Blackfriars Station, would be at the heart of a global exemplar for sustainable infrastructure.”
Source Text and images : www.alliesandmorrison.com. June 2016.
“We believe that greater priority needs to be given to prevention of ill health in public health and social care. All those involved in creating healthy places – public health professionals, planners and landscape architects – need to recognise that landscape has enormous potential to improve our health and wellbeing.”
Source: Honold, J., Lakes, T., Beyer, R. & van der Meer, E. (2015). Restoration in Urban Spaces: Nature Views From Home, Greenways, and Public Parks. Environment and Behavior. 1-30. DOI: 10.1177/0013916514568556.
Urban nature — such as trees and public parks — is beneficial to human health. A number of studies have found that living close to nature can have immediate positive effects on mental and physical health. However, the longer term health impact of urban nature remains poorly understood. This study investigated how exposure to nature affects health in residents of two inner city neighbourhoods in Berlin. The researchers investigated the links between different kinds of urban nature, including green spaces and views of vegetation from the home, and health. To do this, they assessed life satisfaction, perceived general health and levels of cortisol — commonly known as the stress hormone — in hair samples from 32 participants.
Changed patterns of cortisol in the blood have been linked to depression and psychological stress. Over time, elevated levels of cortisol suppress the immune system and can therefore also contribute to other illness. The authors hypothesised that the amount and diversity of vegetation visible from the home would affect health. They also thought that more regular use of public green spaces could encourage better health.
They found that views of vegetation from the home (as assessed by photographs) and the use of green spaces (determined by interview) were linked to the amount of cortisol in participants’ hair. Participants’ hair cortisol levels were lowest when their view was of both a high vegetation quantity and diversity. No significant link was found between the view from the home and self-reported general health or life satisfaction.
When assessing the use of green spaces, the researchers found one of the most frequently visited areas to be a local canal with a highly vegetated trail. People who used this trail at least once a week had significantly lower cortisol levels than less frequent users and reported higher life satisfaction, although they did not differ in general health.
Overall, this study suggests that exposure to urban nature in different forms could be related to lower cortisol levels and better life satisfaction, which corresponds with findings made in other countries and continents.
These results provide important considerations for urban development and suggest that adding diverse vegetation to residential streets and backyards, and developing more urban greenways, has the potential to improve human health. The authors recommend that local authorities use this information when designing sustainable and healthy urban areas.
While the authors do note limitations to the study, including sample size, the methods used to analyse vegetation and the extent to which cortisol correlates with stress and health outcomes, their findings have been reinforced by other research. They also propose that hair cortisol analysis could provide a promising new health indicator for future research.
The Dalston Eastern Curve Garden in east London is a thriving community garden, developed on a small piece of derelict railway land by landscape architects J & L Gibbons, with muf art/architecture and Exyzt. The video shows some of the improvements in community health and wellbeing that the garden has brought, providing an oasis in the heart of a busy, noisy, high-density part of the city, where public green space is severely lacking.
This is the first in a series of Landscape Institute videos on landscape and health, featuring some of the landscape projects that illustrated the 2013 publication ‘Public health and landscape: creating healthy places’.