Late October is the height of the autumn color season this year in central Ohio.  The colorful transition of deciduous tree leaves from green to yellow, orange, red and brown started slowly, increased by mid-month and then sprang into high gear recently.  It happens quite fast once it gets going, and it will most likely be over just as fast.

This process has been uneven, with some areas predominantly green while other areas are quite brightly colored, or even with a good portion of their trees bare.  Going to different parks in the area this month has highlighted how local areas can vary significantly in color content.

A brief look at what is going on is in order.  Autumn leaf colors are, interestingly enough, often the result of the color green going away as opposed to leaves changing into brighter colors.  This happens when photosynthesis– the production of nutrients from carbon dioxide and sunlight- starts shutting down.  For technical reasons, green is the predominant color of leaves in the spring and summer when photosynthesis is in full gear.  When the amount of daylight declines, so does the process of generating nutrients, and the green fades as the trees start going dormant and living off of the nutrients stored in their trunks until spring starts the process all over again.  When the color green disappears, other pigments- there all along, but masked until now by the color green- are suddenly visible.  These are the yellow and orange colors we enjoy.  Red colors are the result of sugars in the leaves, and brown is the color of waste products.  Suddenly, all of these colors are visible at once in a riot of seasonal entertainment.

Certain tree species have certain recognizable colors and hues.  Maples cover the spectrum with brilliant colors; beeches are often brilliant yellow, oaks tend towards red and brown.  Walnut leaves turn yellow earlier than other trees; they also lose their leaves earlier as well.

Another fun thing about autumn is that you can identify leaves by looking at them upon the ground.  You can hold them in your hand and study them easier than when they are on tree branches above your head.

Autumn is my favorite season, and the seasonal color show has a lot to do with that.  It’s nice of nature to go out in a blaze of glory, giving us memories to tide us over until spring.