Chlorophyll is the pigment that gives most leaves their familiar green color. It is found inside tiny structures called chloroplasts in leaf cells. Its important job is to absorb light. Energy captured from sunlight starts a sequence of chemical reactions. Using that energy, the tree takes carbon dioxide from the air and water from the soil and builds energy-rich carbohydrates. That stored solar energy fuels almost everything the tree does: growing roots and branches, making

Every autumn, trees seem to perform a kind of magic trick. The green of summer gradually disappears, and forests, neighborhoods, parks, and streets fill with gold, yellow, orange, red, and purple. But those colors are not appearing out of nowhere. Many of them have been there all along, hidden beneath the dominant green of chlorophyll. As days shorten and temperatures cool, trees begin preparing for winter. One of the most visible signs of that prepa-ration is the gradual dis

Every autumn, trees release millions of leaves. We often think of them as the remnants of summer—the colorful evidence that chlorophyll has disappeared and the tree is preparing for winter. But a fallen leaf isn’t really the end of the story. It is the beginning of another one. Once a leaf reaches the ground, it becomes part of one of nature’s most important recycling systems. Its nutrients return to the soil, its carbon becomes food for decomposers, and it can provide shelte