Cooling effects of greenery in City of Antwerp

Residents of (large) cities can attest to this: during hot summer months, living in the city is often uncomfortable. Sometimes it can even be 5 to 10 degrees Celsius hotter in the city than in the countryside. This is because of the famous heat island effect.

But what exactly is this heat island effect? On the one hand, the temperature in a city gets much higher because of a higher degree of pavement. Moreover, there are many more substances such as asphalt and concrete, which absorb heat and also retain it for much longer. On the other hand, there is often insufficient green space provided that can provide evapotranspiration and cooling. As a result, temperatures do not decrease sufficiently at night and the heat remains in the city. More greenery in the city can therefore effectively help reduce the heat island effect.

Previous research has already shown, in short, that greenery in the city (such as parks, urban flowerbeds, etc.) lowers temperatures and increases urban liveability. But what the effect of greenery in private gardens is, we don't really know yet. All the more reason to investigate.

Those selected to participate in the citizen science project will measure the air temperature under and around trees for several months. This will be done with small sensors, also known as iButtons. All participants will also receive the result of their own tree study at the end of the measurement campaign: what effect does that tree have on the air temperature precisely? And what effect does it have on the liveability of the city?

The “Bomen zijn cool” project is just the beginning. To obtain truly reliable, detailed data, the project should be able to spread over a larger area. However, it is a good start and helps us finetune our already existing tree portal. We have built this tool in cooperation with our Dutch colleagues and are already using it for several municipalities in Flanders. An excellent lever to future, more extensive studies.