Quick Answer
Most people believe that tree moss grows on the north side of trees due to the prevailing northwest winds and the resulting moisture accumulation. However, this theory is largely an urban legend, and the true reasons behind tree moss growth are more complex. The north-facing side myth has led many to assume moss can be used as an indicator for direction in survival situations.
Misconceptions About Tree Moss Growth
Tree moss primarily grows on tree trunks and branches, especially in shaded areas, due to the reduced light intensity and higher humidity. It thrives on surfaces where the air is cooler and the sun’s radiation is weaker. This usually occurs on the north-facing side of trees in the Northern Hemisphere, but the reason is not the prevailing winds as many assume.
The Relationship Between Tree Moss and Direction
The prevailing winds theory is a myth because the growth of tree moss is more dependent on the local microclimate of the tree. The presence of nearby buildings, hills, or other structures can significantly alter the direction of prevailing winds and create areas of high humidity. As a result, tree moss may grow more abundantly on other sides of the tree than the north-facing side.
Using Tree Moss for Survival Navigation
While tree moss can be a useful indicator of tree age and the local microclimate, it is not a reliable method for determining direction. A more effective method for navigating is to use the shadow stick method. This involves creating a vertical stick with a small rock or object at the top. Mark the end of the shadow at a specific time, and then wait for some time and mark the new end of the shadow. The line connecting the two marks will be approximately south, in the Northern Hemisphere, assuming the sun is high in the sky. This method is more accurate than relying on tree moss for direction.
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