Astronomical Fall began this past weekend and here in Muncie we are beginning to see our weather begin to cool. The season of multiple seasons is upon us: Soup season, everything-pumpkin season, the holidays of Halloween and Thanksgiving, and overall a season of change. Some might see that change in their wardrobe. For students the change may come in the form of their grades as they are taking more tests, quizzes, etc.
The biggest overarching change that is linked to Autumn though, are the leaves on the trees. Fall produces some of the most beautiful landscapes across the U.S.A. as the leaves on deciduous trees begin to change color. Perhaps you know why from long ago, or perhaps you’ve forgotten. Either way, lets go through what makes these leaves change.
It all comes back to the process of photosynthesis. This chemical process in the leaves takes place in the cells that contain chlorophyll. This is what absorbs the sunlight that goes through the photosynthesis process and what gives leaves their green color. This is because chlorophyll absorbs blue and red light but reflects green. Different leaves contain different compounds that actually reflect the fall colors we see, but there is so much chlorophyll in leaves that those compounds are masked.
When the amount of daylight decreases and the temperatures get cooler, photosynthesis slows and the chlorophyll breaks down. This then allows yellow and orange pigments to show. As other chemicals break down in the leaves, reds and purples begin to show as well. How vivid these colors are depend on the influences of the temperature, light, and water. Varying combinations of these influences determine how bright or dull the colors are during the season.
If you have the time to go for a walk among the fall colors this year, take a moment to stop and think about the process behind these colors. It might add to your enjoyment of the season. Here are some more pictures to enjoy as we wait for our trees here in Muncie to change.
If you are curious about when we might see changes in the leaves this year, check out this awesome link:
Here’s to a colorful autumn season! Enjoy!
-CWS Forecaster Maurice