As autumn begins sunlight diminishes and the temperatures begin to drop there is not enough water or light for photosynthesis. Now the sunlight is not warming the Leaves with the same intensity of the summer months. Trees begin to rest living off the nutrients stored during the late spring and summer months. As Leaves shut down their internal nutrient factories the green chlorophyll vanishes from the Leaves. When the bright green fades away, we can see the now visible yellow and orange colors. These colors have been in the leaves in small amounts all along, but in the spring and summer other colors are hidden by the dominant green chlorophyll.
How are the bright reds and purples we see in Leaves made? Within some trees, such as Maples the glucose is trapped in the Leaves after photosynthesis stops. Now the sunlight plus cool nights in autumn causes the Leaves to turn the trapped glucose into a red color. The rust and brown color of Trees Leaves as found on Oaks are made from waste left in the leaves.
What conditions cause the most spectacular color display? The weather affects both the leaf color intensity and its duration. The perfect combination for spectacular color display are a warm, dry summer followed by a rainy autumn. Then in autumn, warm, sunny days with cool nights trigger brilliant color formations. If an early frost occurs this lessens the intensity of red. As a photographer I always think a gray rainy or overcast day will intensify the depth of vibrant autumn leaf colors.
For a more detailed scientific explanation please read The chemicals that cause leaves to change color in fall
Hope you all had a glorious leaf hunt this autumn…
Love to ALL!