Any boy scout or girl scout worth their merit badges will tell you: when you’re lost in the woods without a compass, look for moss. As legend has it, moth only grows on the north side of trees, so by finding some moss you can find your bearings. Whether or not you’d know what to do with that information is a different story. But is it true that moss stays on the north side of trees, or is that likely to get you even more lost than before?
It’s an old legend, and it does have some science behind it. Moss thrives in damp, shady, cool environments. Trees generally get significantly less sun exposure on their northern sides than any other side, making the north side the most optimal side for moss growth. But that’s not to say that the legend rings true everywhere.
Moss growth will be most abundant on the northern side of trees – if you’re in the northern hemisphere, that is. If you’re below the equator, moss will predominantly grow on the southern side of trees. A good thing to keep in mind!
If you’re in a shady forest or on a mountain or sloping hillside, it gets a little more complicated. If everything is shady and cool, there’s no reason for moss growth to remain on the north (or south) side of a tree. Many different types of conditions can make a good environment for moss, so unless you can tell for sure that there’s more moss on one side than another, you’re probably better off trying to find another compass.
Of course, in a pinch, you may not have many options. That being said, following flowing water is usually a good idea, as is making sure you don’t lose your compass in the first place!