The true spirit of autumn lies in the concoction of crimson, purple, orange, and vibrant yellow leaves.
Fall can be the best season if you want to walk and have a view of a colorful scene in front of you. Nobody can decline the impeccable beauty that each leaf holds but do you ever wonder why leaves change colors in fall?
In this article, you will know the exact reason behind the changing colors of leaves and other changes that happen in trees during the fall. Why do the leaves fall from trees during winter and why do the leaves remain green throughout the year save for autumn?
So without further delay let us get right into the topic.
Why Do Leave Changes Colors in Fall?
To begin with, the trees that have leaves changing their colors are primarily all deciduous trees. And for the better part of the year, these leaves remain green. And they appear so because of the green pigment present in them called chlorophyll.
I am pretty sure you have heard about this term. And this pigment chlorophyll absorbs energy from sunlight and then photosynthesis takes place. Then the leaves convert the energy onto sugar that nourishes the entire tree.
But during the fall the duration of sunlight decreases and there is a drop in the temperature. Due to less sunlight and low temperature, the chlorophyll starts to reduce and ultimately reaches a point where the other colors become visible.
When chlorophyll reduces the other pigments that were already present in the leaf but were covered due to chlorophyll get revealed and the leaves appear in red, yellow, orange, and purple shades. But there is no certain equation for the change of color of these leaves.
Let us get a little deeper and find a little more about the leaves during fall.
Chlorophyll during fall
As we have already seen that due to changes in the duration of sunlight and the fall in temperature chlorophyll breaks down but why?
The real reason behind this is due to the change in temperature and sunlight duration. Trees stop the process of photosynthesis which is their food-making process. Due to this the chlorophyll slowly breaks down and turns into smaller molecules.
When chlorophyll disappears the other pigments appear exposing the orange and yellow colors. These colors appear due to the already existing carotenes (an orange pigment also found in carrots), and xanthophylls.
During fall you can also see leaves having red color. This dark red color is due to the pigment called anthocyanin. But this color isn’t common in all trees. And there are many articles published on this pigment and on why leaves turn red.
This is unlike other pigments that are there in leaves throughout the year. This pigment along with the residue of chlorophyll gives rise to the purple color.
Therefore only a few trees like Sweetgum (liquidambar styraciflua), Smoke tree (Cotinus coggygria), Sumacs, and a few others a purple shade, or bright orange and yellow.
But as I already said the colors of leaves are not fixed it is because the leaf color that we see in fall is just the mixture of the residue of all the pigment. There are various complexions of autumn foliage and they have changed with time.
Different adaptations of trees during fall
You might have not noticed but along with the change in leaves’ color, there are various changes that happen in a tree. These changes lead to the fall of leaves.
The vessel that carries water and nutrients to leaves slowly starts to shrink. And the point where the leaf is attached to the tree a new layer of cells called abscission layers starts to build up.
And the tissue that is supporting the leaf and keeping it attached to the tree gradually gets severed from this layer. And this is the reason why leaves fall from trees during the winter.
By the time the tree seals cut the leaf, it blows away from the wind or from its weight.
Apparently, most of the trees tend to shed their leaves during the fall. But there are various other trees like oaks which don’t shed leaves untill it is spring and the new leaves arise once again.
Some trees keep their leaves
By the end of fall, most of the trees tend to lose their leaves but there are still a few special trees that don’t shed leaves.
The cell layer called the abscission layer responsible for detaching the leaves from the tree is not grown in various trees untill it is spring.
Also in many plants, it is common for them to lose their leaves partially and in some measure retain their leaves. Usually, the leaves closest to the ground remain on the tree.
Trees like white oak, swamp white oak, and ironwood have this peculiar behavior. The leaves have a small area like they are in the shape of needles or scales that don’t fall and remain greenish throughout the year.
Environment altering the color of leaves
The change in the environment, like in duration of sunlight and drop in temperature, leads to a reduction of photosynthesis and chlorophyll breakdown.
Temperatures lower than usual but higher than the freezing point favor anthocyanin (red pigment). Several trees like black cherry, flowering dogwood, sourwood, white oak, and black oak have brilliant red colors during fall.
But these colors might change their intensity depending on the weather. Like if there is a frosty day the colors become light, when it rains the colors become extra dark and windy days might knock off the beautiful leaves.
The best day to enjoy this entrancing view is usually a day that is clear, sunny, and dry.
FAQs
Why do leaves fall during the autumn?
A layer of cells grows at the place where the leaf is attached to the tree. Slowly the cell layer severs the layers that attach the leaf to the tree and then eventually the leaf falls either due to wind or with their weight.
Do all trees lose their leaves in autumn?
No, not all trees lose their leaves in autumn. As in many trees, the abscission layer responsible for detaching the leaves from trees is not grown fully by the fall.
Why in autumn do the leaves change their color?
In autumn the chlorophyll production is stopped by the plants and slowly the pigment breaks down into smaller molecules. When chlorophyll reduces other colors which were already present in leaves start to show up. And the leaves appear yellow and orange.
Conclusion
The reason why leaves change colors in fall is due to no photosynthesis performed by leaves because of which the chlorophyll breaks down into smaller molecules and other pigments such as carotenes and xanthophylls appear on the leaves. These pigments change the color of leaves to yellow and orange.
Some plants also have red color due to the pigment called anthocyanin. And the change in atmosphere and temperature affects the intensity of the color of the leaves. On rainy days, colors get deeper and on frosty days they tend to get much lighter than usual.