Arborist talks about what makes leaves change color in the fall

As autumn's cool breeze begins to replace summer's sweltering heat, the transformation of the trees' leaves is soon to follow. One of nature's most awe-inspiring phenomena is the change of green leaves to golden yellows, deep reds, and vibrant oranges each fall.

This seasonal change is always greatly appreciated, however often misunderstood. Many believe that cool weather causes leaves to change color. While temperature often dictates intensity, it is just one of the factors that play a part in painting a striking fall landscape.

Seasoned arborist, Rex Bastian of The Davey Tree Expert Company, sheds light on the mystery by explaining the changes seen in trees each season.

“As chlorophyll production wanes and leaves begin to shut down, turn color, and drop from the tree in the fall, other pigments become visible,” explained Bastian. “The yellows, oranges, and browns were always there, only hidden. They are the most consistent annually. The red, pink and purple pigments, however, must be manufactured in leaves during the fall. These colors are the most variable from year to year, because their formation is the most dependent on favorable environmental conditions.”

While the various hues appear to be nothing more than a work of art, there are actually many factors that play a role in the changing color of tree leaves: cooler temperatures, changes in rainfall, and most of all, the shortening of daylight hours.

The U.S. Forest Service elaborates, “A late spring, or a severe summer drought, can delay the onset of fall color by a few weeks. A warm period during fall will also lower the intensity of autumn colors. A warm wet spring, favorable summer weather, and warm sunny fall days with cool nights should produce the most striking autumn colors.”

However, Bastian warns homeowners that, “Trees under stress may discolor or drop leaves early. Extreme heat, drought, insects, disease and damaged roots can all be great stressors for trees. The best time of year to examine your trees for signs of stress is early September.”

Healthy, well-cared for trees showcase the most glorious leaf colors. To ensure trees will offer brilliant fall color, talk to a certified arborist at Davey Tree. Find a trusted tree care specialist at www.davey.com.