Paving paradise: When gardens go from green to grey

Photo by Jaume Meneses – Flickr

Gardens are important in making cities pleasant and enjoyable places to be, but as well as being aesthetically agreeable, they serve other purposes, such as providing wildlife habitat and shelter, enabling food to be grown, mitigating the effect of summer heatwaves, and encouraging biodiversity and conservation.

A recent research project conducted in London has quantified London’s private gardens as a component of the city’s infrastructure and allowed conclusions to be drawn about the effects of changes in private garden space on broader environmental outcomes.

The London Wildlife Trust, in conjunction with Greenspace Information for Greater London and the Greater London Authority conducted the research.

Mapping London’s gardens

Using aerial photographs and digital mapping datasets, and making comparisons over time, the study has been able to measure the contribution of London’s gardens to the city’s infrastructure, in terms of both composition and scale. Gardens from 1998-9 were compared to the same gardens in 2006-08 to identify changes that had taken place in the intervening years. Using a representative sample of 1292 garden plots, the results were then extrapolated to make conclusions about changes to London’s gardens as a whole.

‘This is the first research of its kind for London,’ says the report’s author Chloë Smith. ‘The study not only details the amounts of each kind of ground cover in the capital’s gardens–never previously documented–but also the gains and losses within a decade. This is important to test well-known anecdotal evidence and other localised research.

‘We can empirically demonstrate the importance of London’s gardens. Our research emphasises that gardens are a major and valuable part of London’s greenspace.’

An ‘alarming’ loss of garden land

The study showed that 24 per cent of the area of Greater London is comprised of private garden land. More sobering, however, was the finding that London’s gardens are becoming far less green. Vegetated land in London’s gardens makes up just 14 per cent of the city. This is far less than the 24 per cent figure taken up by the gardens themselves. In 1998/9, 25,000 hectares of private gardens were vegetated, that is, covered by lawn, tree canopy or other plants. However, by 2006/08, this area had dropped by 12 per cent to 22,000 hectares. So although London’s private gardens were still 57 per cent vegetated, the amount of vegetation lost equates to the area of 2.5 Hyde Parks per year.

‘As established by this report, London’s gardens cover a vast area,’ said Mathew Frith, Deputy Chief Executive of London Wildlife Trust. ‘But the speed and scale of their loss is alarming.

‘Collectively these losses detrimentally affect London’s wildlife and impact on our ability to cope with climate change. It’s never been more important that Londoners understand the value of our capital’s gardens.

‘A well managed network of the city’s 3.8 million gardens support essential wildlife habitat and offer important environmental benefits in response to climate change including sustainable urban drainage.’

Gardens sacrificed for fashion and development

So what is happening to these gardens? The major reason uncovered by the study is that hard surfacing, such as decking, paving and concreting, has increased by over 25 per cent. The space taken up by garden buildings, such as sheds, has increased by 55 per cent. These changes are likely to have occurred due to a combination of factors. The main culprit is thought to be the growing adherence to fashionable garden design trends, which favour paved areas over lawn, and which have become increasingly popular through home makeover programs on television. Also thought to be contributing to the change are the maintenance concerns of time-poor residents and the need to sacrifice garden for extra car parking spaces.

Another explanation for the reduction in vegetation is the increase in housing development. Chloё Smith estimates that 500 gardens, or parts of gardens, are lost to development every year in London. That equates to 6 hectares of vegetated land lost to development per annum. Although this is admittedly a small figure from a city-wide perspective, it is argued that at the local level, this could have substantial impacts in terms of wildlife resources, flood drainage and climate change adaptation.

Access to nature threatened

So does the loss in vegetated gardens really matter? The answer is a resounding yes. In its policy statement on gardens, the London Wildlife Trust says that gardens are places where people can experience nature on their doorstep.

“Private gardens form an important part of London’s landscape, and for many people these are the places where they have most frequent contact with nature.”

“The Trust will work to maintain the extent and value of London’s gardens for the benefit of people and wildlife.”

Protecting garden spaces

So how to protect gardens? The loss of garden vegetation is greatly concerning, but there are ways forward.

“Within the problem lies the solution,” says Chloë Smith, in the GIGL July 2011 newsletter. “Our figures demonstrate people’s management decisions have significant cumulative effects at city scale. Londoners have the power to affect their city’s environment by managing their gardens in a different way.”

One mechanism for implementing change is education, so that people become aware of the value of gardens to themselves, to other residents, as well as to wildlife, biodiversity, water drainage and as a counter agent to climate change. This does mean a rather radical approach to private garden ownership, however: the development of a ‘collective mindset,’ where each individual garden is seen as part of a network of gardens, and part of a wildlife corridor or habitat, rather than merely private land for private use.

The London Wildlife Trust also advocates the promotion of organic and sustainable gardening methods, with adequate protection of ecological and biodiversity characteristics of private gardens, including the creation of recognised networks of wildlife habitats. It sees a role for community groups and businesses as well as governments in working together to advocate for the importance of gardens to communities.

This leads to the recognition that planning and legislative restrictions about what work is carried out in private gardens needs to be tightened. This sentiment is supported by the Mayor of London Boris Johnson who has proposed strengthening the London Plan in order to make it more difficult for developers to encroach on gardens.

“The Trust strongly believes that the ecological and amenity values of garden sites should be taken into account prior to development decisions,” it says in the Trust’s policy statement.

“The Trust supports the Mayor of London’s application of the national requirement for planning permission to install impermeable surfaces in front gardens.”

Can compact cities be green?

A more thorny and contentious issue is how compatible compact cities can be with green, vegetated cities. In 1992, Breheny raised the issue of the inherent contradiction between a more compact, higher density city, and a green one. Although a compact city is more sustainable through promoting growth in urban centres and reducing the need for infrastructure and housing expansion on urban fringes, he questioned whether these were the sort of places people actually choose to live in.

As Londoners grapple with loss of their garden areas, and the resulting environmental deficits, the critique of the compact city concept is again raised as a legitimate concern. What is the quality of an urban environment created through a compact city strategy? How can the desire of residents to enjoy green spaces be married with pressures towards higher density living?

Perhaps the last word should go to Danish researcher Anne Skovbro who in ‘Urban densification: An innovation in sustainable urban policy?’ issued this warning back in 2001, which maintains its relevance today:

“If the compact city is to provide a more sustainable urban development, local and regional authorities must balance the strong financial interests in current urban development. And as densification is now occurring, this is not the case. In relation to densification in England, Breheny (1992) has pointed out that ‘the town-cramming that we have witnessed is the result of a piecemeal, largely unplanned activity, carried out without regard for environmental consequences.’ We can conclude that if urban densification is to bring more sustainable development to our cities, a more thoroughly planned densification process is an urgent necessity, consisting of both local and regional perspectives.”