|Leaves from the CA Native Vine Maple (Acer circinatum)|
|Chinese Pistache: a common Bay Area street tree.|
So what makes leaves change color? In order to discuss color, we must first discuss the pigments responsible. Contributing Autumnal pigments from nature's paint palette go as follows:
- Chlorophyll- the green pigment that rocks photosynthesis (converting light to sugar)
- Carotenoids- such as xanthophylls or the more familiar carotene, responsible for yellows, oranges, and brown pigments (as seen in as carots, corn, apricots, narcissus, bananas, etc)- and function to absorb light energy for use in photosynthesis
- Anthocyanins- as the suffix "cyan" suggests, is the red and purple pigment that gives it's color to apples, berries, grapes, cherries, violas, cabbage, etc. They are water soluble and appear in the watery liquid of leaf cells.
In a nutshell, Fall color happens due to two factors: 1.) the breakdown of green chlorophyll (in response to shorter days), which unmasks the already-present orange and yellow pigments (carotenoids) while 2.) the red is from a simultaneous process going on which I mentioned above with the anthocyanins being produced in response to light.
Why are some years so much better for Fall color than others?
|Lagerstroemia (Crepe Myrtle)|
|Poison Oak in Fall|