Yes The Leaves Are Changing. But Why?

ever wondered exactly the cause for leave’s to change? The ND Forest Service explains here:


Bottineau – People look forward to the exciting changes in tree color each fall and often ask the question, “Why do leaves change color?”  Most autumn colors are in the leaves even in the middle of summer, but are masked by the green of pigment chlorophyll.  Chlorophyll captures sunlight and converts it to energy that plants use to manufacture simple sugars and starch for food.  During the summer the tree continually replenishes its chlorophyll and the leaves remain green.

“Color changes are primarily brought on by increasing hours of darkness that occur in the fall season, but exact timing of peak color is also affected by cooler weather,” says State Forester Larry Kotchman.

As autumn approaches, shorter daylight hours and temperatures slow the tree’s food production and the tree uses up its chlorophyll faster than it replaces it.  As the chlorophyll decreases, so does the green color, allowing other pigments that were hidden by the greenness to show through.

Carotenoids—the same pigments found in carrots and bananas—give aspen and birch leaves their yellow, brown and orange colors.  A class of pigments called anthocyanins provides the less bountiful reds and purples of autumn.  The two pigment types combine to create the deep orange, fiery red and bronze hues in dogwood, sumac and oak.

The North Dakota Forest Service encourages people to incorporate leaf watching with hiking, wildlife viewing and other activities in our forests and parks or when driving our scenic highways.  There is bound to be something of beauty for everyone this fall.

The US Forest Service maintains a national Fall Color Hotline from September to November for those interested in following the brilliant fall foliage across the country.  The number is 1-800-354-4595