Why leaves change colors in autumn

Why do leaves change colors in autumn? While some cultures found the answers in the stars, Mountain School students can find the answer on their breakfast plate.

Native Americans believed that a long time ago, as the air was getting colder and the days shorter, three great hunters were pursuing game in vain. With cold weather settling in, the hunters desperately tried to find food for their tribe. They searched for days and days, climbed mountains, crossed rivers, and fought through dense thickets but still could not find any food. Eventually, the hunters found themselves in the celestial realm. One of the hunters spotted the Great Bear and quickly shot him with his bow and arrow. The blood of the bear dripped onto the leaves of the earth down below. In joyous celebration, another hunter pulled out a pot in which to cook the bear meat, while the other hunter lit the firewood he had been carrying. As the pot boiled over, the yellow fat of the bear painted the other leaves on the trees. In the night sky, you can still see these three hunters as the “handle” of the Big Dipper in the Ursa Major constellation.

Red vine maple shows its colors at the Environmental Learning Center

Mountain School students just have to peer at their breakfast plate to find a piece of the autumn colors mystery. During the winter, deciduous trees cannot receive enough sunlight or water for photosynthesis. Additionally, their leaves are too fragile to withstand the chill of winter. Instead, these trees will live off the glucose produced and stored during the summer. As autumn daylight continues to dwindle, the production of green chlorophyll halts, resulting in pigments underneath being revealed. Leaves covered by shade display a yellow pigment, xanthophyll, which can also be found in bananas and egg yolks. Leaves that change orange share a common pigmentation with carrots called carotenoid. Red and purple shades are caused by anthocyanins, a pigmentation found in grapes, beets, and red apples. Formed by glucose trapped in the leaves of some trees, the red pigment thrives during autumn seasons with bright sunlight during the day and cool nights.

Sunlight dances among vine maples

Visits to the North Cascades flaunt this fall’s great conditions for vibrant leaf colors. Pockets of gold and streaks of red, surrounded by green evergreens, paint the landscape. Hearty enough to last the winter, the leaves of evergreens do not seasonally lose their leaves. Evergreen leaves are resistant to cold and water loss, containing a special fluid resistant to freezing.

Highlighted in the New York Times, the North Cascades is home to a deciduous conifer, the subalpine larch, which loses its needles seasonally. The yellow needles are displayed before dropping for the winter. Great hikes for viewing this stunning display include Cutthroat Pass, Blue Lake, and Maple Pass, all trailheads easily accessible from Highway 20. So pack some food containing your favorite fall pigments, and enjoy the stunning season in the North Cascades!

A larch’s vibrant yellow needles against a blue sky backdrop at Cutthroat Pass