HOW DO WE GET THOSE COLOR CHANGED LEAVES?
Chlorophyll usually steals the spotlight, but leaves also contain other pigments (that’s a substance that provides color), including the ones that make carrots orange and turn egg yolks yellow. Without chlorophyll’s green, these pigments finally make themselves known.
Sometimes, trees also produce the same red pigments that give raspberries their color. Leaves make those red pigments only in the fall, and scientists aren’t sure why it happens. But it must be for a good reason, because it takes a lot of sugar — which the tree needs to save up as much as possible. One guess is that these deep reds help protect dying leaves from sun damage, allowing them to collect energy just a little longer. They may also serve as a warning to animals that might otherwise eat or lay eggs on the leaves.
The exact coloring of fall foliage is the result of a mix of these red, orange and yellow pigments. So environmental conditions that change how much there is of each — such as sun exposure, soil moisture and temperature — can make a big difference. Colors vary by species, too.
Eventually, sunlight and frost kill off all pigments but tannin, which is brown. The very cells of the leaf will break down as well, making them fragile and dry. Meanwhile, the tree creates corklike cells to seal itself off from its leaves, even creating a sort of scab where each one connects to the branches. Eventually wind or some other disturbance will break the dying leaf away, leaving the tree with a tiny scar.
That’s how we get those brilliant bursts of color — and wonderful leaf piles to hop around in. In the spring, trees get to make new leaves and start the whole process again.