The trees in Rocky Mountain National Park in colorful northern Colorado are at their best in the autumn months. When leaves start to change their colors, as they are doing here at Bear Lake, they look spectacular!
The rest of the year, when leaves appear green, it is because they contain an abundance of chlorophyll. There is so much chlorophyll in an active leaf that the green masks other pigment colors. Daylight regulates chlorophyll production, so as autumn days grow shorter, less chlorophyll is produced. The decomposition rate of chlorophyll remains constant, so the green color starts to fade from leaves.
At the same time, surging sugar concentrations cause increased production of anthocyanin pigments. Leaves containing primarily anthocyanins appear red. Carotenoids are another class of pigments found in some leaves. The carotenoid production is not dependent on light, so levels aren't diminished by shortened days. Carotenoids can be orange, yellow, or red, but most of these pigments found in leaves are yellow. Leaves with good amounts of both anthocyanins and carotenoids will appear orange.
Leaves with carotenoids but little or no anthocyanin will appear yellow. In the absence of these pigments, other plant chemicals also can affect leaf color including tannins, which are responsible for the brownish color of some oak leaves.
Temperature affects the rate of chemical reactions, including those in leaves, and plays an important part in leaf color. However, it's mainly light levels that are responsible for fall foliage colors. Sunny autumn days are needed for the brightest color displays, since anthocyanins require light. Overcast days will lead to more yellows and browns.
Some digital effects were applied to the original image after the photograph was made. No electrons were harmed during the transition.
Image copyright 2024 Jon Burch Photography
January 28th, 2024
Viewed 54 Times - Last Visitor from Estes Park, CO on 03/03/2024 at 11:18 AM