The common belief that moss only grows on the north side of trees is a misconception. In fact, moss can grow on any side of a tree under the right conditions. The distribution of moss on trees is influenced by a variety of factors, including sunlight, moisture, temperature, and the tree’s microenvironment.
Here are some of the factors that can affect where moss grows on a tree:

1. Sunlight: Mosses are shade-loving plants, so they tend to grow on the shadier sides of trees, which may be the north side in regions that experience significant sunlight on the southern side due to the Earth’s axial tilt. However, in areas with less sunlight or in the Southern Hemisphere, moss might be more likely to grow on the south side of trees.
2. Moisture: Moss requires a moist environment to thrive. It is more likely to grow on the sides of trees that are consistently moist, such as those that are sheltered from the wind and receive higher levels of precipitation.
3. Temperature: Mosses prefer cool, damp conditions. They may grow more on the north side of trees in regions with colder climates because the north side tends to be cooler and more sheltered from the sun.
4. Tree species and structure: The type of tree and its bark texture can also influence moss growth. Some tree species provide a more favorable environment for moss growth, regardless of the direction. Additionally, trees with smooth bark are more likely to host mosses than those with rough bark, which can shed water and inhibit moss growth.
5. Wind and other environmental factors: The side of a tree that is more exposed to wind can be more challenging for moss to grow on because the force of the wind can dislodge the moss or dry it out.

In summary, while moss growth on trees can be influenced by the direction of sunlight, moisture levels, and temperature, it is not accurate to say that moss only grows on the north side of trees. The actual distribution of moss on trees is more complex and depends on a combination of factors specific to each tree’s environment.