Autumn colors are still spotty across The Daily Journal area despite  isolated splashes of deep reds and gold on individual trees.

But the change of seasons is a good time to review some curious facts about trees and their color changes.

For example:

• Changes in sunlight brought on by the shorter days of fall causes leaves to stop producing chlorophyll. That chemical gives leaves their green color during the spring and summer.

• Once chlorophyll is removed, the bright color of the leaf shows through.

• Leaves of some trees such as birches, tulip poplars, redbud and hickory, are always yellow in the fall, never red.

• Trees such as sugar maples, dogwoods, sweet gum, black gum and sourwoods are usually red but may also be yellow.

• Sugar maples only grow in a small area of North America. Illinois is at the southern end of that range.

• Bright sunlight is essential for the production of the red (anthocyanin) pigment in the fall leaves.

• if a black mask is placed on part of a leaf before it turns red, the part of the leaf under the mask will turn yellow while the exposed part will turn red.

• Trees are the longest living organisms on the Earth.

• A mature birch tree can produce up to a million seeds per year.

• Two mature trees produce enough oxygen to sustain a family of four.

• One-third of the United States is covered by trees.

The crabapple is the only apple tree native to North America.