We’re in the peak of the red-yellow season. It’s October 22nd, and nearly all the leaves are still on the trees, likely because there hasn’t been much wind lately. I’m wandering with wide eyes, trying to capture this stunning autumn. This is the beech forest near our home.
I asked Chatgpt why leaves turn out yellow and red during autumn:
Leaves change color in autumn due to environmental and biological processes. The primary reason is the reduction of chlorophyll, the green pigment in leaves that plays a crucial role in photosynthesis. Here’s how it happens:
Decreasing sunlight and cooler temperatures: As autumn approaches, days become shorter, and temperatures drop. This signals the tree to begin preparing for winter.
Chlorophyll breakdown: Chlorophyll, which gives leaves their green color, starts to break down as the tree reduces its photosynthesis activity. The tree begins to reabsorb nutrients from the leaves to store in the roots for the winter.
Revealing other pigments:
Carotenoids (responsible for yellow and orange hues) are always present in the leaves, but the dominant green chlorophyll masks them during spring and summer. As the chlorophyll fades, these pigments become visible.
Anthocyanins, which produce red, purple, or blue colors, are formed in some trees (like maples) in response to sugars trapped in the leaves. Cooler temperatures and bright light increase anthocyanin production.
Purpose of color change: This change is part of the tree’s preparation for winter. By shedding leaves, the tree conserves water and energy since leaves would be too costly to maintain during the cold months when water is scarce.
So, the vibrant reds, oranges, and yellows of autumn result from chlorophyll’s retreat, revealing pigments that have been there all along or are newly produced!
