FALL LEAF LIFE CYCLE: WHY DO LEAVES CHANGE COLORS IN THE AUTUMN
While leaves changing color in the fall is wonderful to watch, it does beg the question, “Why do leaves change colors in the autumn?” What causes lush green leaves to suddenly change into bright yellow, orange and red leaves? And why do tree change colors differently year to year?
- •As summer ends days get shorter, the tree does not have enough sunlight to make food for itself. Rather than struggle to make food through the winter the tree shuts down.
- •It stops producing chlorophyll and allows its fall leaves to die.
- •When the tree stops producing chlorophyll, the green color leaves the foliage and you are left with the “true color” of the leaves.
- •Leaves are naturally orange and yellow. The green just normally covers this up. As the chlorophyll stops flowing, the tree starts to produce anthocyanins. This replaces the chlorophyll and is red colored
- •depending at which point in the fall leaf life cycle the tree is in, the tree will have green, yellow or orange leaves, then red autumn leaf color.
- •Some trees produce anthocyanins faster than others, meaning that some trees skip right over the yellow and orange color stage and go straight into the red leaf stage.
- •You end up with a brilliant display of leaves changing color in the fall.
- •You may have noticed that some years, the fall leaves display is absolutely magnificent while other years the leaves are positively blah — brown even. There are two reasons for both extremes.
- •The fall leaves’ pigment is susceptible to sunlight. If you have a bright, sunny fall, your tree will be a little blah because the pigments are breaking down quickly.
- •If your leaves end up brown, it is because of cold. While leaves changing color in the fall are dying, they are not dead.
- •While maybe knowing why do leaves change colors in the autumn may take some of the magic out of leaves changing color in the fall, it cannot take any of the beauty away.