Leaves are food producing factories for plants. A main component they produce is called chlorophyll, which harvests light from the sun and produces the bright green color that can be seen throughout the summer.
Plants also produce carotenoids and anthocyanins, which produce colors of yellow, orange, and red. During the summer, those colors are blocked due to the high levels of chlorophyll, according to Utah State Horticulture Assistant Professor Dr. Shital Poudyal.
But as weather cools and sunlight decreases in the fall, chlorophyll degrades, showcasing the colors of fall. Poudyal said it’s also a defense mechanism for plants to protect themselves from sunlight.
He said he finds fall in Utah unique.
“Even though our fall is shorter, the length of the fall over our state is longer,” Poudyal said. “If you go up in the mountains, you can see really good fall color. And then after 15 days, if you are down in the valley or in the lower elevation, you can still see fall, whereas in the mountains the fall season would have already gone.”
Park City sees fall before the Salt Lake Valley largely due to cooler temperatures, a byproduct of being at higher elevation.
Poudyal explained that as temperatures cool and sunlight decreases, oxygen production slows. It’s a sign to plants the seasons are changing and it’s time to adapt.
“It’s a natural phenomenon and I wish the fall would last longer and longer, but then as the leaves are changing the plant is also telling the leaves ‘you need to fall off, we are preparing ourselves for winter,” he said.
He said he expects the colors to be especially vibrant this year.
“I think particularly this year, we are going to have very nice fall color. It’s already started because our wet season, we had a really nice wet summer. So I would like to request everyone to go out and see the fall color. It might not happen next year… with this ongoing drought in Utah. I think this year is unique to see and experience beautiful fall color here.”
Local meteorologists expect Utah’s fall colors to peak in early October.
