THE FINANCIAL VALUE OF TREES

Capitalising on the potential of trees
Trees improve quality of life, and may even help city
dwellers live longer, writes Matthew Appleby

Everyone knows trees are valuable. Horticulturists know the value of their crop; garden centres know the value of their stock; customers know how much they are willing to pay for a garden, park or even a Christmas tree. But a recent survey in New York has found trees are worth more than their garden centre label - an average of over £1,840 each thanks to their anti-pollutant value, through natural respiration.

US Neighbourhood Tree Survey Pilot Project researchers surveyed 322 street trees and concluded they had an average value of £1,985 and a total value of over £615,587. The most expensive, a 214-year old tulip tree on Staten Island, is worth £14,200, while the cheapest, a scrawny Ginkgo in the Bronx comes in at just £33.24. A London plane is Manhattan's most valuable at £1,390, scrubbing 12.27kg worth of pollutants per year from the air, the survey noted. The total carbon dioxide, carbon monoxide, nitrogen dioxide, ozone and sulphur dioxide caught by the 322 trees was 145.3 tonnes - £501,037 worth of pollution.

Liverpool City Council Parks and environmental operations manager Giles Nance valued Liverpool's 300,000 park and highway trees at £1,036,800,000 at the Arboricultural Association Conference in 1996. With the policy at Liverpool of two for one replacement, the value of the city's tree stock will continue to rise as long their perceived value in health and financial terms stays high.

Nance said: "I don't see money as being a particular issue because it doesn't cost a lot to plant a tree. Long-term maintenance shouldn't be too much either, as long as you aren't putting the wrong tree in wrong place."

Acknowledging the role of trees
At Trees for London 10th anniversary celebrations last week, it was the UK's turn to acknowledge the contributions trees make. London Mayor Ken Livingstone said: "They make the place more beautiful and much healthier for all of us."

Reports on city life show that living in cities is bad for your health. A study in the American Journal of Public Health in 2000 found that city living increased the risk of death under 65 for men by a factor equivalent to that of smoking. In the UK, latest official figures unsurprisingly found urban dwellers have a poorer life expectancy than country residents. However, recent reports, such as Urban Residential Environments and Senior Citizens Longevity in Megacity Areas: the Importance of Walkable Green Spaces, published last year by Japanese researchers, indicate that life expectancy can be increased if residents have access to green spaces.

The Government has recognised this and as a result £9 million will be available between now and next April from the Living Spaces Programme. Regional director of Groundwork Northwest Ian MacArthur said health trusts could "shift spending from the treatment end towards the preventative end".

"I would advocate Primary Care Trusts to look at the parties involved in the greening agenda like Groundwork and how they can come together and share resources for the best effort."

He added that US environmental psychologist Professor Roger Ulrich's work at Texas A&M University showing patients recover better when surrounded by green environments "begged the question why big hospitals are still building hospital wards looking at blank walls rather than green spaces".

MacArthur commented: "For far too long now, the public's health has been seen in the context of a National Health Service fixated on the treatment of illness, waiting lists and the miracles of medicine. This approach makes little sense in terms of sustainability and creates an economic black hole, which will consume ever-increasing resources for marginal returns. I believe that the wider determinants of health - the social, the economic and the environmental fabric of our communities - need to be prioritised. The communities Groundwork works with are not interested in the differences between the health and the environmental agendas."

A crucial addition to urban areas
Marketing manager of the National Urban Forestry Unit Mark Dixon said that a quantifiable method of looking at tree worth was something that could create a good argument for the "bean counters" to look at. "Instead of trees being seen as a drain on resources, they're coming more in favour rather than being something that needs looking after."

Tree Council chief executive Pauline Buchanan-Black agreed: "It's certainly something we feel very strongly about. We've been running a campaign all this year under the theme 'Trees Matter' trying to get messages like this across."

She said the council aims to demonstrate trees' fiscal and environmental value taking into account wildlife, amenity value, wood products, agricultural value and noise attenuation.Tree Council campaigns director Kevin Hand believes there are a whole host of reasons why trees matter and why everyone should play a part in growing new ones. "Trees help to regenerate neglected areas, bringing more wildlife into the heart of urban areas. They are good for our health, as research is increasingly demonstrating, and help to reduce air pollution, soil erosion and flooding. Yet Britain is one of the least-wooded countries in Europe."

Analysis, 17 July 2003, HORTICULTURE WEEK
Visit the website at www.hortweek.com

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© Edinburgh Tree Warden Network, 2003