Fall- what a great time of year! The leaves start to change from a multicolored green foliage landscape to large splashes of vibrant reds, yellows, and dark and light brown colors. For some, it means raking and bagging, while for others, it means making mounds and playing in them. Experiencing the colorful crunch of dried leaves in our yards extends from childhood memories to other uses. Recently, horticulturists have been recommending shredded leaves or leaf mulch as another form of soil protection. This mimics the natural woodland process of leaves falling and creating nutrient rich leaf humus.

No matter how you plan to enjoy them, the science of the transformation is intriguing.

In the fall, leaves stop their food-making process because of changes in the length of daylight and range in temperatures. The chlorophyll breaks down, the green color disappears, and the yellows, oranges, reds and browns become visible and create each year’s unique fall splendor.

Chlorophyll

It’s the green pigment that gives leaves color in the spring and summer. As the days get shorter and temperatures drop, chlorophyll production slows and eventually stops.

Carotenoids

These pigments are always present in leaves but appear yellow, orange, and brown once the chlorophyll breaks down.

Anthocyanins

These pigments are responsible for red, purple, and crimson colors. They develop in the fall when sugars are trapped in the leaves to form anthocyanins in the presence of bright light.

With this abundance of colors and possibilities,  the landscape becomes a picture-perfect postcard. Many communities, especially mountainous areas, are visited by leaf peepers, hikers, and people who enjoy nature—another reason to get out and explore.

As a landscape architect and someone who knows and appreciates the types of trees in our woodlands, I am always amazed at nature's color display this time of year. What a great time to be in the woods!