Labor Day provides a much-needed respite and last hurrah before the busy season ahead.  Children return to school, gardens are harvested, lawns are renovated, and preparations are made for the following spring.  As we make one final push before winter’s arrival, trees begin to tuck themselves in for their long, winter slumber but not before a final, spectacular show.  We all love and marvel at the fall display.  Some of us even plan vacations and road trips around peak color, but why do leaves, all of a sudden, trade in their green visage for more flamboyant, intense hues?  Hint – it has nothing to do with Jack Frost and is far more involved and interesting.

  Cooler temperatures and shorter days (less sunlight) provide the catalyst for leaves to stop producing chlorophyll, the classic green pigment.  As less chlorophyll is being produced, the leaf’s other pigments begin to leach through.  These other pigments, like yellow, orange, red, and purple are present in the leaves at all times.  Carotene and xanthophyll are present in the foliage all year and produce a yellow pigment.  Other trees also produce anthcyanins which gives foliage its red and purple pigments that mask the carotene and xanthoyphyll’s yellow pigment.   Sunny days and cooler nights fuel the pigment’s intensity because the sugar content of the foliage increases.  That’s why you may see brighter colored red, purple, or orange leaves on the outside of the tree and more yellow toned leaves towards the inside.  It’s almost as if the tree’s true colors are finally able to shine and take center stage.

  As we witness the miracle of Fall, is it safe to say we are finally seeing nature’s true colors?   As trees go into survival mode, conserving energy for the cold, dark winter ahead, are they finally able to reveal themselves and flaunt their individuality?  Sort of.  I mean, scientifically speaking, they don’t exactly spell it out that way, but left to poetic interpretation, it sure seems that way, and there’s something terribly romantic and spirited about the whole process.  Nature, my friends, is a wondrous thing.  But you already knew that.

“How beautifully leaves grow old.  How full of light and color are their last days.”

– John Burroughs

Best wishes,

Kim Sweeney

Hungry for more?  Click on the “Answers Expert” badge on the left side of the screen for more landscape and gardening articles from Answers.com.