As we welcome December, the end of fall is fast approaching. In fact, there are only 17 days left of autumn. While River Legacy and North Texas in general do not see much traditional autumn foliage, there are a few trees that exhibit some fall hues. By now, most of the leaves have begun to fall to the ground, but there are still some trees with their green, orange, brown, red, or yellow foliage.
But, what drives the leaf color change? It has to do with the chemistry inside the leaves and how it responds to seasonal changes. Leaves contain many pigments, including chlorophyll as well as carotenes, xanthophyll and others. Chlorophyll is probably the one most of us are familiar with. This is the pigment that gives leaves their green color. When a plant undergoes photosynthesis, the process by which it creates its own food, chlorophyll takes center stage. It absorbs energy from the sun’s rays to be used in creating this food. As autumn approaches, the temperature gets cooler and the length of sunlight the leaves receive shortens. This causes chlorophyll to break down, making the green color go away. So, leaves are left with the other pigments and these become visible. Carotenes and the other pigments give leaves their yellow to orange colors in the fall. There are other chemical processes at work that add the red hues that are commonly seen as well.
Eventually, the leaves break off the tree. Since trees will no longer be able to make their food during the winter, they go into a state of dormancy where their metabolism slows down. It is a process that is very similar to animal hibernation. The trees are not dead during this time, contrary to what it might seem.
Before all of the leaves fall in a few days, come take a walk at River Legacy to catch a glimpse of some of the beautiful tree color changes in the park and Science Center grounds.