Why deciduous trees go into hibernation
Deciduous trees lose their leaves in autumn. The reason for this has to do with water. A tree supplies its leaves with nutrients and water. It draws the latter from the soil with its roots. In winter, however, this is not possible because the ground is frozen. Therefore, in the fall, the tree withdraws its nutrients, stores them in bark and roots, and takes a rest. Since the leaves no longer receive water, they wilt and fall off.
Now the tree can spare itself to produce new leaves in the spring.