Yesterday, I was at the Timucuan Preserve in Jacksonville where there are the most amazing samples of moss growing on the tall trees. It is said that moss grows mostly on the northern side of trees. An article from "Popular Science" says that this rule applies only in the Northern Hemisphere. In the Southern Hemisphere, it's the opposite.
Moss is probably the best known natural navigation indicator in the world.
For thousands of years, explorers have navigated by following the natural world: the sun, stars, prevailing winds, and even moss. It is also excellent at demonstrating how easy it is to go wrong if you take unnecessary shortcuts.
Tristan Gooley says in 'The Natural Navigator', "For many decades natural navigation has been treated as a skill that is only likely to be used in an emergency. Consequently it has too often been written about and taught as a series of ‘quick tricks’. There are two problems with this approach:
Tricks are never totally accurate.
Tricks are never as interesting as understanding why a method actually works.
If you learn the trick that moss grows on the north side of trees, rocks and buildings then it may help you sometimes, but it will fool you on an equal number of occasions.
If, however, you learn that moss does not care about north or south, but thrives on moist surfaces, then your chances of finding direction accurately shoot up. Moss needs moisture to reproduce."
Gooley also says that a near vertical smooth surface that is not too close to the ground and has moss growing on it likely has only one reason for its surface to stay moist: it is in shade in the middle part of the day when the sun is doing most of its drying. It is very likely to be on the northern side in northern latitudes."
Moss requires damp and shady environments to keep the trees on which they grow, from drying out. But Moss is a Bryophyte, which means mosses can lose moisture very quickly. One of the reasons you'll find moss in cool and shady places, says Fong. And lots of things can create the shady conditions that moss prefers, including the cracks in rocks and boulders and in trees’ shadows in a dense forest. So if you look closely enough, you’ll see moss growing in all directions.
To read Gooley's complete article, check out https://www.naturalnavigator.com/the-library/the-truth-about-moss/