Vegetation has a key role to play in contributing to the overall temperature regulation of cities. Informed selection and strategic placement of trees and green infrastructure can reduce the Urban Heat Island (UHI) effect, and cool the air by between 2 ºC and 8 ºC, reducing heat-related stress and premature human deaths during high-temperature events.

With reduced levels of vegetation and more heat retaining surfaces such as roads and roofs, cities, which are home to over 80% of the UK population are likely to suffer more heat stress than rural areas. Exacerbated by the effects of climate change, urban populations are thereby at risk to a host of heat-related health issues, such as heat stroke and sudden heart attacks, often affecting the most vulnerable. Heat-related mortality has been identified as a key risk to human health, and is reportedly on the increase.

A recent YouGov survey commissioned by Trees for Cities revealed that whilst 86% of UK adults agree that trees are important to help cool our towns and cities, most either underestimate or don’t know the maximum cooling effect of urban trees, which can be up to 8 degrees Celsius (Forest Research).

In addition the survey also highlighted the disparity facing neighbourhoods across the UK in having limited access to trees and their essential benefits. According to the Nature Based Solutions Institute, everyone should be able to see at least three trees from their home; there should be a 30% tree canopy cover in each neighbourhood; and 300 metres should be the maximum distance to the nearest high-quality public green space – the so called ‘3-30-300’ rule. However, the survey revealed that over 37% of UK adults are unable to access trees to help them cool down in hot weather within a 5 minute walk (or equivalent) from their home. The Tree Equity Map shows that most urban areas in the UK have a tree canopy cover of less than 20%, and in some places, it’s as low as 2%.

Trees for Cities is a UK charity working on a national and international scale to improve lives by planting trees in cities.