Have you ever wondered where those amazing fall colors in the Rocky Mountains come from?Even though I know the answer, I still can’t help but ask myself that question every fall.
It is just so incredible to go from the hot, sunny days of summer to the cool, crisp days of fall when the mountains become covered in yellows, oranges, and reds. The change always sneaks up on me slowly. At first it is just certain species of trees that change color, then a few others until eventually all of the trees are different colors or have already lost their leaves.
When the leaves change color the mountains become draped in reds and oranges, and golden yellows. People that normally wouldn’t care about the mountains decide it is time to take a drive up into the mountains to see the fall colors. The bright, vivid colors do not last very long before they fade and the leaves fall off as the trees are ready for winter.
We all enjoy the fall colors, but what causes them?
As you recall trees and plants make their own energy by the process of photosynthesis. Inside the leaves is something called chlorophyl – a chemical that helps make photosynthesis happen. There is a lot of chlorophyl inside of the leaves, which has a green color. All of this chlorophyl makes the leaves appear green during the summer while photosynthesis is happening.
Then in the fall, once the days get shorter, the leaves stop photosynthesis and the chlorophyl disappears. This means that the green chlorophyl is no longer in the leaf and you can begin to see the oranges and yellows that were in the leaf the whole time.
Some leaves, like leaves from Maple trees, turn red. This red color was not in the leaves the whole time, but is created in the leaves in the fall. Certain trees, including Maples, leave some of the food produced during photosynthesis in the leaf. Then the cold nights of fall combine with sunlight during the day to change that leftover food into a red color.
Other trees, such as Oak trees, have leaves that turn brown. This brown color is caused by waste left in the leaves.