FORESTRY UPDATE by Gary Allen Burns 9-7

As days become shorter and nights longer in the fall, the chlorophyll production in the tree leaves slows or stops and the green pigment fades and the yellow carotenes and orange xanthophylls are more visible. Carotenes and xanthophylls are classes of carotenoids, organic pigments.

Carotenoids absorb light for photosynthesis and they protect chlorophyll from photo damage.

Carotenes are hydrocarbons with no oxygen, while xanthophylls contain oxygen.

Carotenoid pigments occur with the chlorophyll pigments in tiny structures called plastids within the cells of leaves. Sometimes they are so numerous that they give the plant a yellow-green color even in the summer, but they usually don’t appear until the leaves begin to lose their chlorophyll in autumn.

The brilliant yellow and oranges can be seen in such hardwoods as ash, black cherry, cottonwood, hickory, maple, sassafras and sycamore.