Autumn tends to be a season full of color and splendor that is reflected in various facets of everyday life from fashion to flowers. Due to chemical processes that take place in trees as summer turns to fall, you’ll see multiple pigments begin to emerge. The pigment that gives leaves their green look, chlorophyll, is essential for plants to make food using sunlight. With less sunlight in the fall, among other factors, leaves tend to look different this time of year. Here are a few reasons why.
Less Chlorophyll Transmission
As mentioned, chlorophyll is a vital pigment that helps leaves make food to sustain themselves. As temperatures become colder and sunlight is less prominent during autumn, less chlorophyll can be produced. As a result, other pigments in leaves, such as carotenes (responsible for photosynthesis) or xanthophyll will become more visible. These pigments range from orange to yellow in color, making them look brighter and more exotic.
Other chemical changes tend to occur as well, forming additional colors such as red and purple. A mixture of chlorophyll residue with other leaf pigments makes such color changes possible. These changes tend to happen before leaves fall off trees as it takes a lot of energy to produce chlorophyll. As a result, energy is saved, which allows the plant or tree to reabsorb molecules and make chlorophyll again whenever conditions get warmer.
Weather Changes
Fall color is influenced by climate change, with temperature, light, and water all determining factors. Rainy days increase the intensity of fall colors, making them more striking. Low temperatures above the freezing mark will allow for pigments such as the water-soluble anthocyanin to form, producing bright red and maple colors.
Anthocyanin is incremental in the sense that it is only produced in the fall while it protects leaves from being sunburned or eaten.
If there is a severe drought, the arrival of fall colors will be delayed a few weeks. A severe frost, on the other hand, can turn leaves brown and cause them to fall early.
In essence, colors change as trees acclimatize themselves going into the winter months. Some trees, such as oaks, get brown-colored leaves because of the waste they leave in the leaves. Particular trees will produce bright colored leaves such as hickories (golden bronze), dogwood (purple to red), and sugar maple (orange-red).
In St. Louis and across the Midwest, leaves tend to start changing color in mid-October.
Other Changes
At the precise point where the stem of the leaf and tree are attached, a layer of cells develops and severs tissues supporting the leaf. The tree seals the cut afterward, so when the leaf falls or is blown off, a leaf scar is left behind. Vessels that supply leaves with nutrients and water are cut off, trapping simple sugars in leaves as well. As a result, the green in the leaves becomes less apparent.
Get a head start on all your tree care needs heading into the fall by calling Jackson Tree Service today!