It has taken me three hours to write this post. Not because it is a difficult topic to write about, but rather because I am blissfully distracted by the beautiful maple trees in my front yard and all the birds and critters hanging around them.
(Sighs) I Love Fall!
And there is so much to love about the season. Today, I will be writing about why leaves transform into all those stunning autumn hues. But in the next few days I will also be writing about and posting reels on fall décor, fun fall outdoor activities, and animal behaviors in the fall as they prepare for winter (and how we can help them).
So, let’s talk about why leaves change color in autumn:
The primary reason trees do this is because of a physiological process which helps them conserve energy and survive winter’s cold.
It’s a Response to Environmental Signals: The green color of leaves is due to chlorophyll. During spring and summer, the combination of chlorophyll, sunlight, and warmer days drives the process of photosynthesis which creates the energy trees need to grow. As days get shorter and temperatures cool, trees begin preparing for winter dormancy. They produce less chlorophyll and gradually reabsorb nutrients from the leaves into their roots and branches. Without a constant chlorophyll supply, the leaves’ green color fades, and other pigments begin to show
Carotenoids (Yellow and Orange): Carotenoids are stable pigments in leaves that stay even after chlorophyll fades. These pigments are responsible for the yellow hues in species like birch, beech, and hickory and contribute to the warm oranges of maples and oaks.
Anthocyanin Production (Reds and Purples): Anthocyanins are different because they aren’t present year-round in the leaves. Instead, trees produce anthocyanins in the fall, especially in response to sunny days and cool nights. These pigments can vary from red to purple depending on the tree species and leaf acidity. Anthocyanins protect leaves from light damage and allow trees to reabsorb more nutrients. Trees like red maple, sumac, and dogwood are known for their brilliant red leaves due to anthocyanin.
Tannins and Brown Colors: As the leaf’s life cycle ends, it loses all chlorophyll, carotenoids, and anthocyanins, leaving behind tannins. Tannins give a brown color to dead leaves, which eventually fall to the ground.
Finally,
Environmental Factors: Temperature, light, and soil moisture influence the intensity and timing of leaf color change. A warm, wet spring; a summer that’s neither too hot nor too dry; and a fall with warm, sunny days and cool nights generally lead to the most vivid autumn colors. However, extreme weather conditions (like an early frost, drought, or heavy rain) can reduce the vibrancy of fall foliage by impacting chlorophyll production and pigment stability.
Here is a short video of my backyard garden for this week.
Have a great day – and go hug a beautiful tree.
