Every autumn, the scenery changes colors.
The leaves of some trees always turn one color. For example, the black walnut turns yellow. Other species, such as sweetgum, turn different colors, even on the same tree.
Sunny days and cool nights are key to fall leaf displays. Bright, sunny days and cool, but not freezing, nights are required for vivid autumn shows. If there is an early frost, the leaves are likely to turn brown and drop.
Although botanists understand the mechanics of some of these changes, other parts remain a mystery.