... I know when you are in the woods and lost you can look at the side of the tree that has the moss on it and tell north from south.

... Which side of the tree does the moss grow on?

Moss can actually grow on the north, east, south, west, or the entire tree.

I think if you're lost and were to use this as your only means of direction, you have to take a look at many trees in the forest to see if moss is all on the same side --- in which case it's likely to be out of the northsomething.

But if you just look at one tree, you're going to get even more twisted around.