Why Are The Aspen So Red?

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At camp this fall, we have a remarkable number of BRIGHT red Aspen. This is unusual, as most of our Aspen tend to be the standard “gold and amazing” types. So what factors are present this fall to create such a remarkable color display?

The timing of leaf coloring til leaf fall is dependent on the increasing length of night. As the days grow shorter, a tree’s biochemical process shifts and its production of chlorophyll slows and eventually ceases. As the leaf’s chlorophyll is used up by the tree, other color pigments—carotenoids and anthocyanins—become visible. According to the USDA Forest Service site, “Both chlorophyll and carotenoids are present in the chloroplasts of leaf cells throughout the growing season. Most anthocyanins are produced in the autumn, in response to bright light and excess plant sugars within leaf cells.”

Carotenoids are responsible for the yellows, golds, oranges and browns in both leaves and in corn, carrots, bananas, and buttercups. Anthocyanins give cranberries, plums, cherries, blueberries, and strawberries their distinct hues. Typically, a tree’s fall color doesn’t vary much from year to year…but this year, we have had a number of unique factors that have contributed to our beautiful display.

  1. Exceptionally dry spring and early summer; all of our trees were highly stressed during that period.
  2. Good rainfall beginning in late summer and early; leaves began producing sugars like crazy to support the renewed growth potential of the trees.
  3. A succession of many warm, sunny days and very cool, crisp evenings.
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Though more anecdotal than scientific, we DO think that the Aspen leaves at camp have more sugars in them than they normally would at this point in the fall because of both the late rains and the very warm days. Anthocyanins are produced during these “lots of sugar lots of light” conditions—and then, with the very cool evenings, the veins of the leaves gradually close—leaving behind the gorgeous reds, and purples of the anthocyanin pigments. Additionally, because of the late rains, the Aspen seem to be a little behind schedule….it is just the beginning of October and many Aspen are still a bit green.

It is almost as though the trees are celebrating this gorgeous end of summer and early fall–and trying to postpone the inevitable long, cold winter days ahead. We hope YOU will continue the celebration with us as we post more fall photos on our Facebook and Instagram pages. Together, we will virtually enjoy these beautiful fall days and, if you are in the area, come on up for a visit…the Aspen will be blazing the trail home.

Photo credit: Nell Davis

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Ariella Rogge
About Ariella Rogge

Ariella started her career at Sanborn when she was twelve. After five years of camper and five years of Sanborn staff experience, she continued her work with kids in the high school classroom. Ariella and her family returned to Sanborn in 2001 to take on the Program Director role which she held til 2012. She and Elizabeth Marable became co-directors of High Trails in 2013. She lists mountain golf, Gymkhana, climbing mountains and making Pad Thai in the backcountry as some of her favorite activities at camp. Ariella received a B.A. in English from Colorado College and is a certified secondary English educator,an ACCT Level 2 Ropes Course Technician, an ARC lifeguard, an AHA CPR trainer and WEMT. She lives at camp with her husband, two sons, 8 chickens, 2 salamanders, 2 hermit crabs and 1 cat.