Do you ever wonder why leaves change color? Is it because they are dead or dying during winter months? No — the real reason that leaves change their color is because the chlorophyll, a pigment in the chloroplasts of plant cells, starts to break down. 

Because the chlorophyll is used to absorb the sun’s energy during photosynthesis, chlorophyll levels drop in the fall, when there is less sunlight. According to the Smithsonian, when the levels of chlorophyll drop, we start to see the red and yellow pigments in the leaves that had been masked by the high levels of green chlorophyll. 

While many would think that the loss of chlorophyll would be harmful for the tree, the truth is that it is a vital part for tree health! You may ask: how is this possible? How can breaking down chlorophyll be vital for tree health? 

The answer is found in the chloroplast, an organelle in plant cells, which plays an important part in photosynthesis. When the chlorophyll breaks down, the chloroplast is actually being shielded from the sun during the fall months. According to Harvard Forest, the broken-down chlorophyll acts like a sunscreen for the chloroplast so that it is preserved until spring. 

You may also notice that some trees turn a dark red or burgundy color. This happens because of a chemical reaction in the plant cell, which produces anthocyanins in response to trapped sugars. Anthocyanins are not just another layer of sunscreen, but also antioxidants and nutrients for the trees! Knowing all of this, we can come to appreciate the process of fall leaves and fall in general with a new, more scientific light.  

By Tvesha Patel ‘27, Photography Editor

27tpatel@montroseschool.org