How green are our gardens?
23 November 2011
How green is gardening? That was the question posed by Professor Diane Pataki in the inaugural RHS John MacLeod Lecture today (23 November).
“In general terms we tend to feel that greening our towns and cities must be good but it is not as simple as that,” said Professor Pataki, (pictured), an urban greening expert and adviser to the US Government from the University of California.
“There are benefits but we mustn’t forget the costs such as the use of water and fertilisers,” she said.
Professor Diane Pataki, who spoke about the issue when interviewed on the BBC Radio 4's Today programme, encouraged her audience and city planners to look more closely at the balance between the environmental costs and benefits of urban greening.
More research needed
According to Professor Pataki the effects of vegetation on local air temperatures affect the climate in desirable ways but there are environmental and economic costs that have to be taken into account. For example, fertilised landscapes may emit greenhouse gases such as nitrous oxide. There are very large species differences in the way that horticultural plants use water, which affects the way that gardens mitigate flooding, storm water and the urban heat-island effect.
“We need ways to determine whether our landscape designs are effective in providing the services we intended,” she said. “There is a great effort at the moment to design methods to monitor and validate greenhouse-gas emissions but there are few programmes to measure the effectiveness of green spaces in meeting the needs of city dwellers. This needs urgent attention.”
Welcoming Professor Pataki to the lecture Dr Roger Williams, Head of RHS Science, said, “It is an honour to have a world-renowned expert on urban greening give the inaugural lecture and this speech has set an extremely high standard for future speakers. Urban greening is an important topic for the RHS and we are working with a number of groups across the UK to carry out more research into the benefits.”
Adviser to the US Government
Professor Pataki is based at the University of California, Irvine where she is Associate Professor, Earth System Science in the School of Physical Sciences and Associate Professor, Ecology & Environmental Biology and Director of the Centre for Environmental Biology, both in the School of Biology. She also advises the US Government and is on the board of Scientific Counsellors of the US Environmental Protection Agency and the Carbon Cycle Scientific Steering Group for the US Climate Change Science Programme.