Which direction are we looking in the photo above?
Clue: how many colours can you see?
We are looking north.
There is a bright patch of Xanthoria lichen on the bark of the tree.
This is the ‘colour compass‘ lichen. The closer to orange it is, the more direct sunlight it receives and the more likely it is to be facing south.
Apologies to those who are colour blind. Natural navigation uses shapes more than colours, but on this occasion it is a colour clue.
(On the right, eastern side of the tree, at the same level, you might just be able to make out a patch of the same lichen, but a drabber grey-yellow-green colour.)
In case you’re interested, I’ve added a photo of the branch shape of the tree. This picture is taken from the same spot as the one above, at the same time. We are looking up into the branches reaching out to the southern light.