Autumn colors. Fall colors have been late this year, including the beech leaves in my picture.

As green chlorophyll pigments that manufactured food for the tree decompose, their nitrogen and phosphorous compounds are exported to the roots for re-use next spring. During the process, yellow carotene pigments that helped the chlorophyll to capture sunlight are revealed.

Another family of pigments, called “anthocyanins,” paints the reds and purples of autumn landscapes.

Long thought to be an accident of autumn chemistry, anthocyanins are now believed to act as sunscreens, shielding leaf tissues from sun damage during the interlude when chlorophyll compounds are being dismantled and recycled.