Who’s to Blame for Drab Fall?

By Edie Grossfield, Post-Bulletin, Rochester, Minn.

Oct. 19–Minnesotans look forward to the reds, yellow and oranges Mother Nature paints on the landscape in October, but the weather in our region this year has made autumn rather drab.

Some people guess the dull greens and spotted yellows on our maples and aspens must be the drought conditions southeastern Minnesota experienced early this summer. Actually, it has more to do with fall’s warm temperatures and lack of sunlight, said Jana Albers, a forest health specialist based in Grand Rapids for the Minnesota Department of Natural Resources.

“The fall leaf color, especially in the maples, oaks, birches and aspens, is based on having warm, sunny days and cool nights, like below freezing,” she said. “When you have long periods of rain and overcast weather, the sunlight just doesn’t break down the chlorophyll (in the leaves) as rapidly and the change is slower and less spectacular.”

Northeastern Minnesota, where Albers lives, had extreme drought this year. Yet, the autumn leaves were quite colorful due to cooler temperatures and plenty of sun, she said.

When chlorophyll in leaves is not broken down by the sun, its components return to the tree roots and store there for the next growing season.

Rochester City Forester Jacob Ryg said the warm weather coupled with many rainstorms that knocked leaves down early in the season have contributed to the lackluster landscape.

“The oaks have just started to turn, and they’re usually more muted colors. The sugar maples and red maples are the most vibrant and they lost their leaves early,” he said.

While drought wasn’t a factor in leaf color this fall, it is having an impact on tree health. Drought conditions next year could result in the loss of some Rochester trees, Ryg said.

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