The importance of urban forests: why money really does grow on trees

A must-read article in today’s Guardian.

This month will see representatives from the world’s cities convene in Quito, Ecuador, for the United Nations conference on sustainable urban development,Habitat III. An agreement called the New Urban Agenda will be launched, to address the challenges facing a growing global urban population that already accounts for over 50% of us.


Here are some of the article’s headline points:

  • Green spaces are essential for mental and physical health, community building and performing urgent ecological tasks.
  • The ecological services that trees provide are staggering.
  • Trees can cool cities by between 2C and 8C. When planted near buildings, trees can cut air conditioning use by 30%, and, according to the UN Urban Forestry office, reduce heating energy use by a further 20-50%.
  • It’s hard to put a price on how an avenue of plane trees can muffle the roar of a main road, although trees do on average increase the value of property by 20%.
  • When the New York City park department measured the economic impact of its trees, the benefits added up to $120m a year. (Compare that to the $22m annual parks department expenditure.) There were $28m worth of energy savings, $5m worth of air quality improvements and $36m of costs avoided in mitigating storm water flooding. If you look at a big tree, says Jones, “it’s intercepting 1,432 gallons of water in the course of a year.”
  • Trees can bring down cortisol levels in walkers, which means less stress.
  • It is suggested that, in areas with more trees, people get out more, they know their neighbours more, they have less anxiety and depression.
  • Research suggests people are less violent when they live near trees.
  • A tree psychology study was done in Toronto by psychology professor Marc Berman, using data sets from the national health system. He discovered that, if you have 10 more trees on a city block, it improves health perception as much as having £10,000 more in income, or feeling seven years younger. There are even some studies on urban trees which showed that they reduce health inequality.
  • The value we place on trees and nature is informed by childhood experience. A Child growing up dislocated from nature will suffer, say some researchers, an “extinction of experience”. Sadly, these children will ultimately understand and value nature less.

You can link to the full article here.


Author: BristolTreeForum

We are a group of volunteers dedicated to increasing the tree canopy cover of Bristol.

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