I know many of us enjoy the leaf colors we get in Virginia every fall, but have you ever wondered why the leaves change color? In a recent trip to the mountains I saw a large cascade of different colors which made me wonder why some leaves turn one color and others turn another. It turns out there is a scientific reason (go figure).
The primary function of leaves is to convert sunlight into food. This is done with a green pigment called chlorophyll. When fall approaches, and the days get shorter, some plants can no longer get the amount of light (food) required for active growth. When this happens, the plants will begin to enter a dormant state. During this state, the plant is no longer producing chlorophyll. As the green pigment begins to fade, it leaves behind other pigments, which were always in the leaf, but deteriorate slower.
Leaves that are yellow or orange contain the pigment carotene. This is the same pigment that gives carrots their orange color. Reds and purples are caused by pigments called anthrocyanins. These are the same pigments that give radishes and roses their color.
As these pigments fade, tannin becomes the predominate pigment left which gives leaves their brown color. It is right before this occurs that the plant will detach the cell walls around the stem of the leaf. At this point the leaf is connected by its veins which are easily broken. As the wind blows, it breaks these veins and the leaves fall to the ground.
Leaves are still changing across much of Virginia, so it is not too late to plan a visit to one of our state parks to witness this for yourself. Reserve America.
If you have a fall foliage picture of a Virginia State Park you would like to send us, email me at [email protected] and I may include it in our Facebook album. Please include your name and the park it was taken at so I can give you the proper credit.