A study of urban nature conservation suggests a more ecological style of planting could pervade the cities of Northern Europe
'The theme of the book reflects the current fashion among landscape professionals in Northern Europe towards the production of more natural landscapes where ecological criteria are taken into account and attempts are made to encourage wildlife within the urban fabric.' Urban Nature Conservation* is written firstly for policy-makers and for professional creators and maintainers of urban green space. Although most architects are not directly involved, there is still much to interest them in understanding this shift in a key element of the urban environment. It may affect any urban planting - verges and traffic islands, old parks and new, building settings and graveyards.
Many of the issues will be broadly familiar - the natural and sustainability, approaches to conservation, community involvement, cost-cutting and the harmful effects of cct (compulsory competitive tendering), environmental education, style wars.
So what is being conserved? The highest goal for ecology is to preserve the diversity of species. Rarely is it the case, however, that urban areas are home to any endangered species. Nor, as a general urban landscape policy, would it be practicable to turn most urban green space into a series of artificial ecologies - 'plant zoos' - for conservation of rare species. It is too public, too disturbed, too polluted, and landscape budgets are already stretched.
Could we at least preserve, or at least create and maintain, a set of natural landscapes - conserve natural landscapes as systems? According to the book's authors, Kendle and Forbes, there are no natural landscapes left in Northern Europe, only what is slightly disparagingly known as semi-natural. Could we then re-invent them; what could these be like? The authors draw a useful distinction between the aesthetic design of landscapes and the process (dynamics) of a living landscape. For some people, a natural landscape by definition has no intervention from man. It is just process. Colonies of native species are left to get on with it, dynamically competing. What results is nature's design of landscape. Man destroyed the natural; all he is allowed to do is give it a chance to start again.
One of the most extreme recent workings out of this approach can be found in Germany, notably Munich, interestingly a place with some authoritarian history. Non-natives are not admitted. Municipal lists of plants that are native and naturalised have to be followed where planning permission is required. 'Even where two or more family houses are to be built, a separate freespace plan (Freiraumplan) must be produced, showing that the development will be accompanied by enough trees, a high percentage of which must be native.' (In the private areas, exotics are permitted.)
In streetscapes there is sometimes encouragement of 'spontaneous vegetation' - species mixes that arise without planting. In Stuttgart, for example, this has happened with blocks of roadside verges where previous ground- cover planting has been removed and there is now an initial mix of common, aggressive perennials (known to others as weeds - a very value-laden concept in this context).
The authors do not record whether the public applauds the look of this as much as the intention. And even if the planting began instead as a wildflower meadow, a currently popular landscape (at least in the flowering season), succession is likely to lead over the years to a general scrub. Today few people find this lifts their hearts, though some landscapers hope we will learn to love it.
Such plant genetic cleansing is a minority approach. Most of those favouring ecological planting are ready to include exotics (non-natives). The focus on system dynamics remains - of planting that achieves a competitive balance rather than plant-mix control through maintenance of individual plants. In Germany some very complex mixed perennial plantings have been tried, but have had to be fenced, regularly supervised and given specialist maintenance to keep at bay the pernicious influence of man and his ally, the unwanted plant.
For most landscapers, management should have a major role in ecological approaches to planting, though more by trying to go with the flow than imposing a regime. It is early days for this more ecological approach; the knowledge of which plants will co-exist successfully in which habitats is still being developed. Clients cannot yet be so readily assured about future success, the landscape forms that will develop and the maintenance requirements.
Some clients, notably local authorities, have welcomed more-ecological approaches to planting for their apparent promise of lower maintenance costs. After all, the cost of maintaining Wimbledon Common is 3 per cent of the cost for Kensington Gardens. Unfortunately, the general picture is that maintaining traditional and ecological landscapes can cost much the same, though there are some significant exceptions. The authors point out that the cost of a season's 16 grass cuts with a gang mower can be comparable to scythe-cutting a wildflower meadow twice a year. More management precision tends to be needed for ecological plantings, especially with the deskilling of the labour force. And management needs to be more responsive to the way the planting develops, which allows less pre-programming, which in turn does not sit well with price-driven outsourcing of maintenance and cct.
A few other popular conceptions are also given the critical treatment in a book which puts forward many other opinions. For example, the authors point out that ecological planting is not necessarily any better for wildlife than formal planting, just different, and not necessarily any help in conservation. It is no use being good for wildlife; for conservation the focus has to be biodiversity, hence being good for threatened species.
Another misconception is the idea of urban planting as a functioning green lung. It may usefully raise the spirits. But 140 mature trees are needed to compensate for the co2 emissions of one driver. And 30-40m2 of typical green space is needed to supply the oxygen needs of one person.
Along with others, the authors conclude that the main conservation role of urban planting is educational, to change our culture, to get us to care and act globally to preserve biodiversity. They say, 'Any global fight to preserve biodiversity (on present terms) is already lost.' The action needed to preserve biodiversity happens in the countryside but the decisions are made in the city, where the people are. To win, change them.
Greening the city
The authors discuss the historical threads woven into current ecological landscaping approaches - for example, the English Landscape Movement which, despite the apparent naturalism of, say, country estates, wanted the hand of man to be clear; passing on to Gertrude Jekyll, who was happy to include exotics. This is all interesting, but it is a professional history, not a history of popular culture. The jury has hardly arrived yet to start deciding whether it likes the new urban ecological planting now emerging. Efforts to rig the jury, some successful, have been made by trying to involve local people in new planting schemes, especially in Germany and the Netherlands. The authors warn against expecting too much of public commitment for too long.
They address the practicalities and institutional issues of moving to more ecological planting in some detail. Planners, for example, can do relatively little. Sometimes they include ecological planting as part of planning gain, but are not able to insist on continuing maintenance beyond five to 10 years. Where there is to be new planting, such as around major infrastructure works, the planting agenda could be shifted. As with other styles, change toward ecological planting will come by infiltration, by a new generation of landscapers moving in.
As for the public, the authors see ecological landscapes making their own argument, by appealing to the human spirit. Added to some traditional landscape appeals, a more ecological approach can provide 'more delights, more sounds, more colours and more scents - not just the scent of flowers but of hay and the fallen leaves, the sight of dragonflies dancing in the sun, the colours of fungi emerging from the litter beneath trees, the sparkle of spider webs in the fog, the sound of bees humming around heather'.
The ambition, say the authors, should be to break down the dichotomy between town and country. Nature needs to be an integral part of urban life, of urban thought. At the level of understanding ecologies, who can object? At the level of a 'current fashion among landscape professionals', there appears to be no debate about the nature of urbanity. Do we like cities because they are distinctly different from the country?
* Urban Nature Conservation. Tony Kendle and Stephen Forbes. E & F N Spon (Routledge), tel: 0171 583 9855. 352pp. £35.