The plants trap polluting particles like natural air filters, and protect against flooding, too.
Hedges and trees in towns and cities are more than just attractive, they can behave like natural air filters, trapping traffic pollution made up of dangerous microscopic particles blamed for a range of serious health problems, ranging from heart disease, asthma and strokes to diabetes, obesity and dementia.
A study at Lancaster University showed that silver birch trees maintained as hedges at about the height of an adult person were particularly good at cleaning the air.
Their leaves are covered in tiny hairs and ridges that help trap the polluting particles and each time it rains the particles are washed off the leaves, freeing them to trap more particles. The suggestion is that the trees could be planted at pollution hotspots.