A reader in Stony Creek, New York, submitted this photo of a bubbly substance at the base of a yellow birch. What’s brewing here?
Answer
Foam can form at the base of trees during or after a rainfall. The water dissolves accumulated chemicals on the surface of the tree bark, air gets added to the mix as the water flows down the tree, and the result is this sudsy-looking foam at the bottom of the tree.
This week’s contest winner was David Govatski