You probably heard about the amazing capacity of trees to cool down cities.
The process behind that is called Evapotranspiration and is beautifully exhibited in the video below.
Evapotranspiration can be broken down into two parts:
Evaporation: Water from the soil is absorbed by the tree's roots and transported to the leaves. Some of this water evaporates directly from the surface of the leaves into the atmosphere.
Transpiration: Water that is absorbed by the roots also moves up through the tree to the leaves, where it exits through small pores called stomata as water vapor.
As water evaporates from the leaves, it absorbs heat from the surrounding air, creating a cooling effect. This process is similar to how sweating cools the human body.
The cooling effect of evapotranspiration can be significant.
A mature tree can transpire up to 400 liters of water a day, which can provide cooling equivalent to several air conditioners running for the same period.
Apart from this, trees also provide shade of course and the roots of trees create channels in the soil, improving its structure and allowing water to infiltrate more effectively.
This promotes groundwater recharge and reduces surface runoff.
In summary, if you are in city management, plant more trees.
Thanks to Hicham En Nakhla for showing me the video and to ARTE for creating it.
