The simple answer is this: Leaves fall off trees so that the trees can survive the winter. ... During that process, the trees lose a lot of water – so much water that when winter arrives, the trees are no longer able to get enough water to replace it. And so now we know.

What causes the leaves to drop?

A sudden change in temperature, be it cold or hot, can lead to foliage turning yellow or brown and dropping off. Wet or Dry Conditions – Many plants will drop their leaves as a result of overly wet or dry conditions. For example, overwatering commonly results in leaf yellowing and the dropping of foliage.

Why are so many leaves falling?

Drought. Drought-stress is one common reason for trees dropping leaves in summer when it gets really hot. Some trees are more prone to scorching and drying up quicker than others. But when trees are not receiving enough water, their leaves can start to die and fall off.