Before the leaves fall, the tree stops producing , the pigment that makes them green. As the green fades, other pigments like carotenoids (yellows and oranges) and anthocyanins (reds and purples) become visible. Eventually, a specialized layer of cells forms at the base of the leaf stalk, acting like a seal that pushes the leaf off and protects the branch from infection.
Throughout the summer, leaves accumulate waste products and heavy metals. Shedding them is a way for the tree to "take out the trash" before entering its dormant phase. The Biological Process: Abscission tree shed their leaves in
When the tree receives the signal to prepare for winter, it stops producing chlorophyll. As the green pigment fades, other pigments that were present in the leaf all along—hidden behind the curtain of green—are unmasked. Before the leaves fall, the tree stops producing
As the chlorophyll breaks down and the colors emerge, the tree begins to construct a special layer of cells at the base of the leaf stem, where it attaches to the branch. This is called the . Throughout the summer, leaves accumulate waste products and
Understanding and why trees shed their leaves reveals the hidden rhythms of the natural world. The Timing: When Do Trees Shed Their Leaves?
However, a leaf is also a liability. It is covered in thousands of microscopic pores called . These pores open to let in carbon dioxide and release oxygen. Unfortunately, they also allow water to escape through a process called transpiration. During the spring and summer, this is not a problem; the tree draws water from the soil through its roots to replenish what is lost.