Why Do the Leaves Change in Autumn?

The bright colors make autumn the favorite season of many kansans.

Humans, it seems, can argue about almost anything. The other day, I witnessed a couple of people arguing about what triggers leaves to change colors. “Shorter days!” exclaimed one. “Cooler nights!” proclaimed the other.

As with most “I am right and you are wrong” arguments, the answer lies somewhere in between with both being important but the intensity of the sun is by far the bigger factor. This is, in part, due to the shorter days, but even more-so due to the lower angle of the sun.

Trees require a substantial amount of sunshine, water and carbon dioxide to produce a green leaf. Reduce any of those and the leaves aren’t as vibrant as they would otherwise be.

Mark Bogner is a proud kansan with a degree in atmospheric science from the university of kansas.

What makes for a “perfect” leaf year? The main thing is a healthy tree. If there has been plenty of rain throughout the growing season along with plenty of sunlight and nutrients, good color should result. This can be greatly enhanced, however, by mild, sunny days and cool, clear (but frost-free) nights.

So as you enjoy the great leaf color this fall, know that several factors have lined up just right to produce such a spectacular show for north central Kansas and the Flint Hills!

A longer form of this article by Mark Bogner appeared in the latest edition of Keynotes. This edition is packed with information on Medicare Open Enrollment, SHICK Counseling, and avoiding Scams, plus our many special features. Are you on our mailing list? If you haven’t received Keynotes in the past but would like to, contact us and we will send you a copy!