Every fall, a certain store advertises back-to-school supplies while a choir sings, ‘It’s the most wonderful time of the year.’ I suppose after a long busy summer, many parents feel that way; however, there are others who share the same sentiments but they happen to be childless! To many, autumn is the most wonderful time of the year. They enjoy the cooler brisk morning air; they stop to breathe in the scent of smoke from burning leaves; they watch in wonderment as colored leaves drift down and cover the earth, and they turn into children as they purposely step off the path just to walk through crisp leaves.
(I happen to enjoy all of the above and I hate to admit it, but it is not my favorite time of the year.)
Although it isn’t my favorite season, I admit I find it has some interesting features. For example, did you know that in Korea, newspapers inform their readers when it’s the best time to check out the autumn colors? National parks are the favorite destinations. One park in particular is exceptionally beautiful at this time of year. Seoraksan is one of the most famous for ‘leaf watching.’ In Japan, people go ‘hunting for the autumn colors.’
Ah, but why do the leaves change color? What determines if it will be red or gold? Or, like me, have you wondered that if you stared long enough, could you see the color changing? Well, probably not.
The process begins when the days become shorter and the leaves receive less water and nutrients. A separation layer forms at the base of the stalk and it blocks off any circulation from the leaf to the rest of the tree. What happens? The leaves eventually fall to the ground.
However, while this is taking place, carotenoid pigments turn the leaves from green to yellow or orange. This pigment isn’t noticed throughout the summer because green chlorophyll is the predominant color. The red color comes from anthocyanin, a pigment that leaves don’t produce until the autumn. When the chlorophyll breaks down, the leaves become yellow and red. When the chlorophyll is completely gone, a Poplar leaf turns yellow and the Maple leaf changes to red.
Of course, we have to factor the climate in too. For example, the amount of anthocyanin produced depends on the weather – clear sunny days with cool nights produces the most pigment. Where do we find this climate? In the Far East.
This whole process is practical as well as beautiful. Trees conserve water and energy during the winter and also rid themselves of toxic wastes that build up in the leaves during the summer.
What happens to the billions of leaves that fall on the ground? This organic material is converted into humus, a vital ingredient of fertile soil. So not only do all those beautiful colorful leaves bring us joy as we stop and stare at them in wonderment or as we listen to them crunch under our feet, they also provide fertilizer for next year’s growth!
And that, my friends, is the end of your science lesson for today. Actually, it was so interesting that I find myself wondering why autumn isn’t my favorite time of year.
Simply put: I can’t help thinking of what is coming – winter! That is why spring is my favorite time of year. At least, here in central Canada, there might be five more months of warm weather.