Public domain photos

The image shows a close up of a tree trunk with a ruler next to it, and on the bark of the tree there is a patch of lichen. The lichen is a vibrant green color, and the ruler is a standard measuring tool used to measure the size of the lichen on the tree.

The image shows a close up of a tree trunk with a ruler next to it, and on the bark of the tree there is a patch of lichen. The lichen is a vibrant green color, and the ruler is a standard measuring tool used to measure the size of the lichen on the tree.Open in library