Why is it so cool under a big tree?

Why is it so cool under a big tree?

Because the tree is luxuriant, that is to say, the transpiration of the tree is better, the transpiration of the tree is better, that is, the tree is transpiration more water, water evaporation is conducive to cooling!
Transpiration is the process of water loss from the surface of living plants (mainly leaves) to the atmosphere in the state of water vapor