James A. Surrell, M.D.

Autumn, also known as our Fall season in the USA and in Canada, is one of our four great seasons, that is followed by our Winter, Spring, and Summer seasons. Of course, Autumn marks our transition from our Summer season and leads us to our Winter season. Autumn is our season when the duration of daylight becomes noticeably shorter and the temperature cools considerably. The first day of Autumn this year was on Monday, Sept. 22.

The amount of daylight time decreases during our Fall season and night time darkness increases as the season progresses until the first day of Winter. The first day of Winter this year will be on Sunday, Dec. 21. This date is also known to have the shortest amount of daylight. Here is an interesting Fall fact. On the first day of Fall, on Sept. 22, the hours of day time daylight and of night time darkness are just about equal. After Dec. 21, the first day of Winter, our days will start to get longer by about 2 minutes each day. This will then lead to about one extra hour of daylight by mid-January.

One of the great features of our Upper Peninsula Fall season is the striking change in the color of the leaves on our many beautiful trees, as they prepare to shed these leaves. These shorter days of the Fall season serve as a sign to the trees to begin to prepare for winter. The reason for this is that during winter there is not enough light for photosynthesis to occur, so as the days become shorter throughout autumn, the trees begin to close down their food production systems and reduce the amount of chlorophyll in their leaves. Chlorophyll is the chemical which makes tree leaves green, and as it declines, other chemicals become more prominent in the leaves. These other chemicals are the cause of the vibrant ambers, reds and yellows seen in the autumn leaves. These tree chemicals that cause these beautiful leaf color changes are known as various types of flavonoids, carotenoids and anthocyanins.

Now it is time for some silly Fall humor.

* Humpty Dumpty had a great Fall. And I sincerely hope you also have a great Autumn.

* What did Autumn say to Summer? Make like a tree and leave.

* What happens when Winter arrives? Autumn leaves.

* What do trees say when their leaves grow back in the Spring? What a “re-leaf.”

I wish you all a fun Fall season enjoying the beautiful tree leaf colors in our wonderful Upper Peninsula.