Autumn is a bright and beautiful season full of vibrant foliage, but why do leaves change color?  To understand this process, we have to explain the process of photosynthesis.

Why Are Leaves Green?

Image Courtesy of Homegiudes SFGate

Plants absorb sunlight which transforms the water and carbon dioxide they have absorbed into oxygen and glucose.  Glucose is a kind of sugar which plants use as energy; glucose is a fundamental building block in the life of a healthy plant.

Photosynthesis is the process by which plants transform water and carbon dioxide into oxygen and glucose.  Chlorophyll  is a chemical plants have which assist  in the process  of photosynthesis.  Chlorophyll is what gives leaves their green color.

When Leaves Change Color . . .

Once summer shifts into fall, and the days become shorter, there is less sunlight and water for the plants to absorb, therefore the plants must rest and live off of nutrients they have stored for winter.

As the bright green color fades from the leaves, we are able to see different colors which have been present in the plant all along.  The absence of chlorophyll makes it possible for us to see the underlying colors, from shades of red to plum.

Bright, Beautiful Autumn Leaves

Photo Courtesy of National Geographic

Some trees, such as Maple trees, keep glucose trapped within the leaf structure long after the photosynthesis process has come to a halt. A combination of cool fall temperatures and sunlight sparks a chemical reaction which transitions these leaves from green to a vibrant red.

Now that you know why leaves change color, enjoy a lovely walk through our beautiful New England foliage!