Cool trees

When it is hot, one of the best places to be is under a tree. You don’t need a scientific study to tell you that.

But research shows just how important that cooling is and why access to trees will matter increasingly as temperatures rise.

The effect is strongest in towns and cities. Concrete, brick and tarmac absorb heat during the day and release it slowly, making built-up areas considerably hotter than their surroundings. Trees help by keeping the sun off roads and buildings. They also release water through their leaves, cooling the air around them. As the IPCC puts it, trees “locally dampen the amplitude of heat extremes”, taking the edge off extreme heat. Research in London estimated that the city’s existing urban forest helped prevent 153 heat-related deaths between 2015 and 2022. Increasing tree cover further could provide additional protection.

But the benefit of trees is not shared equally. Mapping in England shows that less affluent neighbourhoods often have fewer trees and poorer access to good-quality green space. This leaves some communities with fewer ways to escape extreme heat. That makes urban tree cover an issue of fairness when it comes to good environmental and town planning.

Trees also make a practical difference on farms. Forestry Commission guidance says that farm trees can cut solar radiation reaching livestock by as much as 58%, with animals’ skin temperatures recorded at around 4°C lower than in open pasture while providing shelter from wind, rain and cold at other times of year.

The role of trees in absorbing carbon is well known. In tropical regions, they also move vast amounts of water from the soil into the atmosphere, cooling the land and shaping weather conditions far beyond the forest itself. The picture is more mixed in snow-covered northern regions, where dark forest canopy can absorb more heat than open snow.

This summer, severe heat, drought and wildfires across Europe have brought another question: can having more trees increase the danger of fire?

There’s no single answer. Wildfire risk depends on weather, ignition sources, vegetation condition, forest structure, and landscape management. Dense, uniform plantations can be more vulnerable to severe fire than diverse forests and landscapes. That is why European guidance increasingly emphasises mixed species, varied structures, and active, locally appropriate management.

The answer, then, isn't simply to plant more trees. It is to protect existing forests and restore damaged landscapes well. For ITF, that means working with communities, using species suited to local conditions, building in diversity and caring for trees long after planting.

Trees give us shade on a hot day. At a larger scale, protecting and restoring forests and bringing more trees into farms and cities, can help keep landscapes liveable as temperatures rise. It is a benefit we can no longer take for granted.

Help plant planet cooling trees

Trees do far more than provide shade. They help communities adapt to rising temperatures, protect wildlife and restore the landscapes we all depend on. Donate today and help plant and protect trees where they can make the fastest, most lasting difference.