Urban tree campaigner Alice Whitehead shows why the trees on our streets and in our parks are so important.
Trees are good for us and the planet. It’s a fact. But nowhere are the benefits of trees felt more strongly than on our city streets and town doorsteps.
Urban trees bring a greener view, cleaner air and create biodiverse, wellbeing corridors that breathe life into the monotonous grey. And with more than 80 per cent of the UK’s population living in the built environment, the establishment of ‘urban forests’ has never been more important.
Urban trees are not a new phenomenon in the UK. When tree-lined boulevards began popping up in continental cities in Europe in the 19th century, public figures and horticulturalists began to put pressure on the government to follow suit.
While it might have started as an aesthetic movement, gradually, as the expanding suburbs absorbed farmland and field boundary trees – the Victorians began to see how trees were an antidote to overcrowding and industrial pollution. Many of the mature species we see on our streets today – the common lime, the plane tree, the sycamore and the horse chestnut – were planted during this time.
But it wasn’t until much more recently that scientific studies revealed their true value. No single human-made asset can match what a mature street, park or garden tree can deliver in terms of urban cooling, air-conditioning, water filtering and stormwater management.
The reason? Tree canopies act as oversized nets, intercepting harmful urban pollutants such as carbon monoxide, ammonia and sulphur. It’s thought a single tree can absorb as much as 48lbs of carbon dioxide per year, releasing enough oxygen back into the atmosphere to support two human beings.
Further research shows that street trees can lower surface and air temperatures through evapotranspiration and by providing shade. This combats the ‘urban heat island’ effect, which sees urban areas reach temperatures eight to 12 degrees higher than rural areas.
Fallen leaves, flowers, fruits or other tree parts also form mulches that provide a natural filter for polluted rainwater, and bark and roots absorb and reduce water run-off, which reduces the chances of stormwater flooding.
Trees are also natural traffic calmers. Tree-lined streets appear narrower and can be used as an alternative to bollards and speed bumps. And they dampen road noise by up to 50 per cent, through reflection, deflection and absorption.
So, what does this mean for city dwellers? Above all, quieter, cleaner and safer streets. Studies have shown communities in tree-rich neighbourhoods have stronger relationships and interact more with others. There are lower rates of crime and littering, and improved wellbeing and health.
Of course, trees also connect us with nature, offering vitally important habitats to insects, birds and small animals.
Threats to urban trees
But while this Victorian legacy might have grown bigger in stature over the years, in many UK towns and cities, trees haven’t always increased in number.
Roads, factories, housing developments and utilities have taken their place. And coupled with shrinking council budgets – which often view trees as a cost rather than an investment – many older trees have been taken out and never replaced.
Worse still, poor public perception, apathy and misinformation, as well as fewer experienced Tree Officers, has led to healthy trees being chopped down for simply nudging kerbstones out of place or dropping leaves.
People power is changing this. Many cities are showing they can reach and exceed the recommended 20% tree canopy cover target.
Catch a London bus, and your trip might take you under the city’s ever-growing tree canopy – which now totals eight million trees. Birmingham has also recently been recognised as a ‘Tree City of the World’ for its 1 million trees, with plans to increase this number by 30% by 2026.
How does your area compare? Is it time to lobby your local council and find out how it plans to increase tree canopy cover?
If you feel there isn’t enough being done for trees in your city or town, get in touch with a tree charity or organisation (see this list) Or create your own group – and fight hard to retain, maintain and grow your leafy, green neighbours.