Why Fall Colors Are Different Around the World

The colors of autumn are different all around the world: in America, they take on a hot and blazing shade of red, while in Europe, they are almost always yellow. Hasn’t it puzzled you why the fall-blooming colors differ depending on which side of the world you’re on? I certainly was surprised to find out that in different regions of the world, we have different autumnal colors; I thought they were all the same!

Groups of researchers were just as interested, and they have developed a likely idea why the fall colors are different around the world. But first, we need to know about the pigment processes.

Pigment chlorophyll is a molecule found in the fresh, green leaves of the spring and summer, and they allow plants to capture sunlight and make energy in the process of photosynthesis. Chlorophyll is extremely sensitive to coldness, so when summer slowly fades into the cooler fall, plants stop producing it. Then the yellow and orange pigments take over the dominating green color of the leaves. These new, colorful pigments that we see commonly during the fall season are called carotenoids.

I mentioned yellow and orange, but what about red? The hues of red prove to be a lot more complicated than the colors of yellow and orange. This is because the red color comes from a substance different from carotenoids, called anthocyanins, and the difference lies in the times they are produced. The pigments of carotenoids can be shown when the green fades away, but are always present in the leave’s color. The mechanism of anthocyanins is different because they only produce in the fall.

This concept is a lot harder to comprehend from my reader’s point of view, but my perception on the leaves of autumn has now broadened as I feel this is something very important to understand.

Now we can talk about the idea on color evolution: the idea states that in larger areas in the world, they are covered with green forests and tropical jungles, and there is a phase in which series of ice ages and dry spells occur. This results the species of trees to drop their leaves for winter.

In North America, the “north-to-south mountain chains enable plant and animal migration to the south or north with the advance and retreat of the ice according to the climatic fluctuations,” says Simcha Lev-Yadun of the University of Haifa-Oranim in Israel, “and, of course, along with them migrated their insect ‘enemies’, and the war for survival continues.” East Asia goes along the same concept.

In Europe, “the mountains— the Alps and their lateral branches— reach from east to west, and therefore no protected areas were created,” says Jarmo Holopainen of the University of Kuopio in Finland. As a result, the tree species that did not survive the cold died and so did the insects that depended on them. The trees that had survived in Europe had no need to survive with the insects that had died out, and thus did not need red leaves since the red pigments were believed to be able to ward off pests that munched on the trees’ leaves— in my opinion, I think it is because red is a very brilliant and warning color.

Did you know...

Did you know that carotenoids (the yellow and orange pigments) are responsible for the orange color of carrots?

Did you know that anthocyanins (the red pigments) act as sunscreen for trees? They block the harmful radiation of the sun, preventing overexposure of light, and they also act as anti-freeze so the leaf cells won't freeze during the autumn chill.

Links:

Why Fall Colors Are Different (http://www.livescience.com/environment/090922-fall-leaves.html)

Autumn Leaves Picture (http://casarobles.info/wp-content/uploads/2008/11/2-autumn-leaves.jpg)