To conserve energy during the winter!

In the winter the Sun isn't at its peak... more at its weak!
So Some trees, do not produce leaves or fruits and goes dormant, during the winter break!

Winter is a time of rest for nature, Plants don't grow either and many animals leave areas where snow falls. The only animals that stay are predators as Winter is a good time to forage for animals who hibernate underground!

Winter means death, and in early times the word death and snow meant to same thing: Winter is the time the year dies! Spring is when it comes Alive again!

All animals need heat to survive because heat means Alive!
When your body is warm your alive... if your body is cold your Dead!

Winter is a time of Death so leaves die in the Winter!