Autumn Leaves and Fall Colors: Nature Facts and a Poem
Autumn and the Death of Leaves
Many people find late autumn a depressing time of year, unlike the start of the fall season. In many parts of the world, the early autumn burst of color is glorious. The leaves change from green to vivid yellow, orange, purple, red, and russet, and—best of all, I think—a mixture of different colors in the same leaf. The ripened fruit is celebrated in harvest festivals and there are still occasional days that are warm enough to remind us of summer.
As autumn progresses into winter, though, it may seem as though death has the upper hand. Leaves are shed and begin to decay, many plants die, and dried, shriveled, and inedible fruits hang on bare branches. Most animals disappear and bird song is silenced. A cold dampness fills the air and soaks the ground. The days are short and color seems to have been drained from the landscape.
Despite the lack of color and activity, I don't find late autumn depressing. Most plants are dormant, not dead, and I know that they will produce new leaves in the spring. The bare trees have a beauty of their own and evergreen plants still maintain their color. The bright red holly berries are a special treat in late autumn, winter, and early spring. New catkins emerge before the year is over. Even when death has occurred, the nutrients in the decaying bodies will be recycled and will enable new plants to grow. The soil is rich with potential.
Fall is a time of rest and potential. The annual plants that have died have left their seeds behind to start new lives. Flowers will reappear in the spring and summer and fresh fruits will form. Animals will return—and in my area some never leave—and birds will sing again. The cycle of life will continue.
Chlorophyll in Green Leaves
Three categories of pigments exist in leaves—chlorophyll, carotenoids, and anthocyanins. The relative amounts of these pigments vary throughout the year and determine the color of a leaf.
Leaves appear green in the spring and summer because they contain a green pigment called chlorophyll. Pigments of other colors are present too, but they are usually masked by the chlorophyll. There are two main types of chlorophyll in a leaf— chlorophyll a and chlorophyll b. These absorb light of different wavelengths, or colors.
Chlorophyll plays a vital role in the life of a plant. It absorbs light energy, which the plant uses in photosynthesis. During this process, carbon dioxide from the air and water from the soil react to produce a sugar and oxygen. The sugar is the plant's food. In the fall, chlorophyll breaks down, revealing the pigments that give leaves their traditional and often very beautiful autumn colors.
Yellow and orange carotenoids and red anthocyanins produce the beautiful colors of leaves in autumn. The pigments also give color to many fruits and vegetables and may have health benefits for humans. Carrots, oranges, and mangoes are three foods that are rich in carotenoids. Red cabbages, cherries, and blueberries are three foods that contain anthocyanins.
Why Do Leaves Change Color in the Fall?
The yellow and orange carotenoids in fall leaves were present during the summer but were hidden by the chlorophyll. The carotenoids helped photosynthesis by absorbing specific wavelengths of light and passing the energy to chlorophyll. The red anthocyanins were made in the late summer and early fall, however. The color of anthocyanins depends on the pH of the environment, so they sometimes look purple instead of red.
There are several theories that attempt to explain why anthocyanins need to be produced in leaves that will soon die, but at the moment there isn't a definite answer to the puzzle. One theory is related to the fact that the chlorophyll degrades as the leaves age and other harmful changes in leaf cells occur. The anthocyanins may help the leaves by protecting them from light damage at a critical time, enabling them to make as much food for the plant as possible before they fall to the ground. This may be at least a partial explanation for the color change in some plants.
For a few wonderful weeks, the beautiful fall colors of leaves are visible. Eventually the leaves are shed and the plant uses stored food to stay alive. In the spring, the amount and intensity of light increases, chemical reactions in the plant increase in number, and new leaves develop, allowing more food to be made.
Red cabbage juice is used in school science experiments because its color indicates whether a substance is an acid or a base. Its anthocyanin molecules are red in an acid and blue or green in a base.
What Is Consciousness?
The poem below describes a tree losing its leaves in late fall. In the poem I imagine that plants and the elements of nature have consciousness, an idea that has supporters, although not amongst most scientists.
Consciousness is a mysterious phenomenon that is still not understood. In general (although there are exceptions), scientists believe that consciousness is created by processes occurring in the brain. Once the brain ceases to function at death, the person's consciousness no longer exists.
Some people have different ideas, however. One theory is that everything has consciousness—even the cells that make up the bodies of living things and the atoms that make up matter. Another is that there is one universal consciousness and that our brain accesses this consciousness during our lives. We may influence it just as it influences us. According to this view, consciousness is still present after our bodies die.
"The Four Seasons" is a set of four violin concerti composed by Anton Vivaldi and published in 1725. The first movement of "Autumn" represents a country dance and the joys of the harvest. The second depicts a period of relaxation after the revelry and drinking. The third depicts a hunt with horses and dogs. The piece below is played by The Academy of St Martin in the Fields. The violinist is Julia Fischer.
An Autumn Ritual
The cold wind plays around the tree,
bound by ancient duty and desire,
and secret knowledge of the Earth,
her powers and her needs.
The golden canopy responds
with joy and thrilling sympathy,
and branches sway in partnership
while leaves vibrate in ecstacy.
The strengthened wind works in delight
and leaves shake wildly in return,
yearning to cooperate, and
sensing wonderment nearby.
At last the bonds begin to break
and leaves detach triumphantly,
then frolic in the boisterous wind
to celebrate their victory.
The leaves fall far away, in grace,
and join the carpet on the ground
where understanding slowly dawns
as decay produces clarity.
Freedom from control reveals
a world much wider than before,
awareness stretched a billion fold,
discovering all that is.
Then slowly memories fade away
while insight clouds and shrinks,
atoms pulled to recombine
as nature builds again.
So now the cycle starts anew,
formation and decay,
forgetting then remembering
until the end of time.
© 2011 Linda Crampton