sealPurdue News


September 1995

Fall leaves show the colors they've carried all summer, expert says

WEST LAFAYETTE, Ind. -- Although looking at the fall colors is a cherished American pastime, the spectacle of nature is more intricate than most people realize.

The leaves aren't dying because they've been killed by frost. The changing of colors is an active process of the trees preparing for winter.

Robert Joly, professor of horticulture at Purdue University, says the first step to understanding the process is to know that tree leaves have three primary pigments:

Source: Robert Joly, (765) 494-6997; Internet,

Writer: Steve Tally, (765) 494-9809; home, (765) 463-4355; Internet,

NOTE TO JOURNALISTS: A color photograph and a computer graphic showing the scientific processes that cause fall colors are available. Contact Steve Tally at (765) 494-2096.

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