As the days get shorter and the weather cools, trees prepare for winter. The green color we see all summer comes from chlorophyll, a pigment that helps trees capture sunlight to make sugar through photosynthesis. As daylight decreases and temperatures cool, trees produce less chlorophyll and the green begins to fade revealing yellow and orange pigments called carotenoids. Some trees also produce anthocyanins, which create brilliant red and purple colors.
Why do trees go through all this color-changing drama? It’s all about survival. During winter, frozen ground can make it difficult for trees to absorb water. Dropping their leaves helps trees save water and energy. Before the leaves fall, trees pull valuable nutrients from them and store those nutrients for later.
Trees also form a special seal, called the abscission layer, where each leaf stem connects to its branch. This layer gradually separates the leaf from the tree until the leaf eventually falls.
The weather also affects the show. Sunny days, cool nights, and moisture can create especially vivid fall colors. So, the next time you admire the autumn leaves, remember: these beautiful colors are part of a tree’s adaptation process for surviving winter!
