If you are like a lot of us, you probably have been asked by a child or inquisitive adult, ‘Where did the green go?’ when looking at autumn leaf color. You could tell them, ‘The same place the white goes when snow melts,’ and hope they don’t push the subject. But it seems that the snow answer doesn’t suit some little brainiac and they push for more information. If you want to stall for time as you don’t know the answer, tell them, ‘As the snow melts and the water either enters the ground or runs off, the white enters the air and forms the clouds you see in the sky.’ This just might frustrate them enough to get you off the hook where they drop the subject and you won’t look as if you don’t know the answer.
Or, you could go for the short answer and tell them that the 3 main factors affecting leaf color change are: the increasing length of night means the leaves are getting less light; weather changes and the tree cuts off water and nutrients from getting to the leaves; and, the biochemical processes in the leaves change where the chlorophyll that gives them their natural green color decreases and stops but the other two pigments remain and take over.
If that isn’t enough for the bow-tie wearing little nerd, you could maybe baffle him/her with some of the following.
Remind them that chlorophyll is necessary along with sunlight in the photosynthesis process for the leaves to manufacture sugars for their foods. Carotenoids, which produce yellow, orange and brown colors are also present with the chlorophyll in the chloroplasts and don’t leach out of the leaves like the chlorophyll does. Anthocyanins, the third pigment found in leaves, are produced during the fall in response to the bright light and extra plant sugars. They produce the reds, oranges, blues and purple colors in the leaves. After the chlorophyll is destroyed, the carotenoids and anthocyanins are unmasked and show their colors.
If that doesn’t do the trick, continue with the following. Temperature and moisture are the two big environmental factors that influence the brilliance of the colors during and after the loss of the chlorophyll. For the best color, warm, sunny days and cool, crisp nights are needed. A late spring, or a severe summer drought can delay the onset of color in the fall. If we have a warm spell in the fall, we can expect a lower intensity in the colors as well. For the best fall colors, a warm, wet spring, good summer weather, and a warm, sunny fall with cool nights is needed.
Still not enough information for the little bugger? Different species of trees produce different colors. Oaks turn red, brown or russet; hickories turn golden bronze; aspen along with yellow popular turn a golden-yellow; dogwood, popular here in the south, turn purplish red; beech trees turn light tan; maples vary by species; red maple turns a brilliant scarlet; sugar maple an orange-red; black maple a glowing yellow while striped maple becomes almost colorless. Other trees, such as the elms, show very little color other than a drab brown.
Hopefully, you’ve baffled the little darling. If he/she needs more information tell them to contact the county agent or extension director in their area. A landscaping specialist or nursery owner would be another good source to pawn them onto. Just hope that they don’t ask you what causes the leaves to fall after they’ve changed color. If they do, RUN, don’t walk.
Keep your fork