Why don't the leaves of the date palm fall?

With the help of its root hairs, the tree picks up more water than it needs and sends it throughout the body. Excess water leaves the body in the process of sweating. Suppose in winter, the leaves can continue this evaporation even if water occurs. There is a process of dropping the leaves to get rid of it. But since date palms are dry (desert) trees, they cannot collect excess water. So it goes without saying that evaporation does not happen. For this there is no need to drop its leaves.