Why Do Leaves Change Color?

Some of us are fortunate enough to live in an area of the world with annual leaf change from the brilliant greens of spring and summer to the vibrant yellows, oranges, and fiery reds. During the fall months as the temperatures start to decrease and the days shorten there is an explosion of color unlike any other.

If you have witnessed the awe inspiring, jaw dropping display you know exactly what I am speaking of. Have you ever wondered why leaves change color and fall off of their branches?

Today during a hike near my house MtnMama and I walked through a wonderful mix of Ponderosa pines, Douglas firs, Blue spruce and Quaking aspen. The aspen were the trees that brought us to this hike and lured deep into the forest as we became entranced by the delicate beauty of the white trunks now alight with every phase of color change you can imagine.

I knew a little of why these leaves turn color and fall but I did not know exactly what was going on so I read up on it and here is what I discovered.

The true cause of the color change is due to the lengthening nights. You see the leaves have chlorophyll in them as a means to capture ultraviolet light and through a chemical reaction called photosynthesis they can turn the light into sugars that feed the tree. Trees store this sugar to make it through the winter months long after the leaves have dropped.

There are three basic coloring agents in a leaf.

• Chlorophyll, which gives leaves their basic green color. It is necessary for photosynthesis, the chemical reaction that enables plants to use sunlight to manufacture sugars for their food. Trees in the temperate zones store these sugars for their winter dormant period.
• Carotenoids, which produce yellow, orange, and brown colors in such things as corn, carrots, and daffodils, as well as rutabagas, buttercups, and bananas.
• Anthocyanins, which give color to such familiar things as cranberries, red apples, concord grapes, blueberries, cherries, strawberries, and plums. They are water soluble and appear in the watery liquid of leaf cells.

Now as the days grow shorter, the chlorophyll looses its ability to make simple sugars and slowly dies off. With its death the Carotenoids and Anthocyanins take over and are able to display there vibrant colors. These colors are displayed until the leaves are shed in anticipation of the cold winter months.

The color displayed is affected by the warmth of the day and cool of the night. The greater the difference between day and night temps- the more vibrant the display.

Fortunately around the west we are seeing a particularly vibrant display.

I got a good deal of this information from this site. All of the pictures MtnMama and I took during our hike this morning.