Forests evolved during Earth's prehistoric past. Since then, all forests have developed in essentially the same way, by means of a process called succession.

The First Forests

The first forests evolved from ferns and other prehistoric plants that, over time having adapted to the surrounding environment, grew more tree-like. Trees that preferred a warm, humid, tropical climate developed first, followed by those that were adapted to drier, cooler weather. The first deciduous trees evolved about 180,000,000 years ago.

About 1,000,000 years ago, during the great Ice Ages, glaciers (slow-moving masses of ice) covered much of the planet and destroyed many of the world's forests. By the time the glaciers finally retreated to where they are today, about 10,000 years ago, they had scoured the land of plants. As time passed, deciduous birch trees were among the first to return to the regions once covered by...