I took the photograph below of some tree rings. Each division on the ruler is 1 millimeter:
Each tree ring (the areas between the pizza crusts) represents one seasons worth of growth. The growing season is from about March to October. My question is about the small lamellae or dark bands that make up each ring. I have placed a green box around one set of these bands. What are they?
These small bands all seem to be the same width, so tree rings that are wider (good years) have more of them, and rings that are narrow (drought years) have fewer.
What are these bands?