When the temperature drops below zero degrees Celsius, water freezes. Plants cannot make use of frozen water in photosynthesis. If the water contained in the cells of living organisms freezes over, the structure of the cells are destroyed. 

When the winter arrives, a layer of snow often covers the ground. For many animals, it makes both movement and searching for food more challenging. Invertebrates die or spend the winter in brumation, and the animals that eat them likewise either hibernate or migrate elsewhere.


A birch forest during the winter.

Although wintry forests can look still and lifeless, that is not the case. Both plants and animals have developed various ways to survive the cold, harsh winter. Some plants, for example, adapt to the winter by dropping their leaves and gathering sugar into their roots and rhizomes.