A Breath Of Fresh Air

More and more often we are coming across serious scientific research that backs up our sense that our urban trees are good for us, not just because they look stunning, but because they are making a significant contribution to our health in our gritty city environments. 

A case in point is research recently presented on BBC2's "Trust Me I'm A Doctor" in which the work of Professor Barbara Maher at Lancaster University's Environment Centre revealed the huge benefits of having a screen of the humble (but beautiful) silver birch (betula pendula) placed between houses and busy roads.

After just two weeks of monitoring the effects of the tree screen, the reduction in the amount of iron-bearing particulate traffic pollution was found to be an astounding 50-60% (compared with a row of adjacent houses without the screen). 

Apparently, much of the effect is due to the tiny hairs and ridges on the leaves which collect the pollution. The open structure of the tree canopy also allows the free circulation of air. Each time it rains, the pollution is washed off and the effect is renewed. Given that particulate matter in car exhaust is a serious risk to those with heart disease, this common tree species could provide a relatively inexpensive safeguard for those living along busy city roads. Oh yes, and it's a beautiful tree too! 

(With thanks to Anthony for spotting this item).

Useful links: 

1. British-trees.com entry for silver birch - go here

2. BBC link http://www.bbc.co.uk/programmes/p01dgd9c/features/pollutionexperiment

3. Professor Maher's research paper - go here

Silver Birch outside the Tate Modern in London - February 2008

Notable birch (betula pubescens perhaps?) - Yorkshire Dales - summer 2012