Red, Gold, Yellow and Orange: Fall Colors Hidden Beneath the Green

While all seasons provide something new to see in the Forest Preserves of Cook County, fall may arguably be the most visually stunning time to get out and explore. There are still some late-blooming wildflowers, and of course, canopies are exploding with vibrant colors. But what exactly is causing the leaves to become red, gold, orange and yellow?


Rebecca Collings, Forest Preserves’ senior ecologist, explains that leaves aren’t actually turning a different color—different pigments that have always been present are just becoming visible.


“We always hear people ask, ‘When are we going to see the leaves change?’ But the tree isn’t necessarily changing colors. As the tree prepares for winter, it decreases its chlorophyll production, the green pigment that helps plants photosynthesize. Other pigments are present, but are masked by chlorophyll,” Collings says. “When trees stop making chlorophyll, these other pigments become more visible, and that’s when people will see the radiant yellows and oranges.”


Why do trees stop photosynthesis? There is still sunlight during winter.


For trees to photosynthesize—the process plants use to convert sunlight into energy—they absorb carbon dioxide in the atmosphere and water through their roots. Through photosynthesis trees are able to produce carbohydrates to make tissues and grow.


“In order to absorb the carbon dioxide, the plant has to open up small holes in the leaf called stomata,” explains Collings. “Doing so is a risky for the plant as they also lose water in the process. Some plants, like our deciduous trees, ultimately decide it is a better use of resources to drop their leaves and regrow new ones next year. Essentially they’re in survival mode till next spring.”


What about the trees that stay green, like conifers and evergreens?


These trees will continue some level of photosynthesis in the winter. They have adaptations like small leaf surfaces, meaning fewer stomata on each leaf, and waxy coatings that limit water loss.


Where can I go to see stunning fall color?


Want to experience breathtaking color this fall? Check out this list of recommended hikes and biking trips:





  • Harms Woods – Park at Harms Woods Central to access unpaved Yellow Trail or paved Red Trail
  • North Branch Trail – Park at Miami Woods, north of Oakton. Cyclists can enjoy a ride through a tunnel of maples


Central – The Salt Creek trail system sees a lot of bicyclists. Consider bringing a bike, or renting one in the Forest Preserves.

  • Bemis Woods – Park at Bemis Woods North for bike rentals and easy access to paved Red Trail
  • Salt Creek Woods Nature Preserve – Park at Bemis Woods North, and walk east along the Red Trail, then north along the unpaved Yellow Trail





  • Jurgensen Woods – Access unpaved Yellow Trail and hike through Jurgensen Woods Nature Preserve
  • Sauk Trail Woods – Park at Sauk Trail Woods Central for bike rentals and explore 3.5-mile paved loop trail around Sauk Trail Lake


How can I learn more?


Prefer guided fall color walks with an opportunity to learn more about nature’s fall art show? Check out these family-friendly opportunities:


Falling into Autumn Walk

Spectacular fall colors to view while enjoying a casual walk in the woods.

Sunday & Monday, Oct 7 & 8 • 1:30 pm

River Trail Nature Center – 3120 Milwaukee Ave, Northbrook


Science of Fall Colors

Discover the science behind how and why leaves “turn” colors this time of year. Program will conclude with a short hike to view fall color.

Saturday, Oct 13 • 10 am

Sand Ridge Nature Center – 15891 S Paxton Ave, South Holland


Fall Color Walk

Enjoy the change of colors in nature’s palette. Join us for a leisurely walk and plant discussion with a naturalist.

Saturday, Oct 20 • 1 pm

Sagawau Environmental Learning Center – 12545 W 111th St, Lemont


Autumn Walks

Explore the beauty of the autumn season on a guided nature walk through the woods and by the pond and river.

Saturday, Oct 20; Sunday, Oct 28 • 1 pm

Trailside Museum of Natural History – 738 Thatcher Ave, River Forest


Autumn Hues

Take in the colors of the season and learn a little about the science behind the changes.

Sunday Oct 21 • 1 pm

Crabtree Nature Center – 3 Stover Rd, Barrington Hills


Fall Color Hike

Be captivated by fall colors while enjoying a 3-mile casual hike through the woods.

Saturday, Oct 27 • 10 am

St. Mihiel Woods – Central Ave, south of 167th St, Tinley Park


Fall Color Walk

Join a 2-mile hike around Lost Beach Trail to enjoy the colorful leaves of sassafras yellow, black gum scarlet, black cherry red and black oak orange.

Saturday, Oct 27 • 1:30 pm

Sand Ridge Nature Center – 15891 S Paxton Ave, South Holland

Visit two of the treasures of the Forest Preserves of Cook County