Why does moss grow facing north?

Moss, once the scourge of the Arctic, was banished long ago by the Ice King. Moss so loved the northern cool climes that it decided to grow everywhere, covering landscapes far and wide with lush green. But the harsh Ice King declared that his kingdom would gleam in white and not green, the color favored by Moss. With this decree, the ice caps began to grow and glaciers began to flow south, wiping clean the earth for the Ice King. Moss could do nothing but run to the south, where it was forced to hide in the shadows. Moss still yearns to return to the land of the north and reminds us daily by growing on the north side of trees, hill sides, and rocks.

Moss, and other associated organisms such as this prefer cooler, moister habitats in which to develop. The northern sides are cooler and moister due to the relative position of the sun and its plane of travel throughout the day and year. This lends to sites which are preferable for their growth.

Moss does not grow well in direct sunlight

Cooler and moister. More hot and dry on sun-facing south side.

global warming, once it was growing both