Tuesday, September 23, 2014

Kids Nature Detective: What causes autumn leaves to turn color?

What is the cause for all those beautiful, fiery colors that make people drive the Adirondack highways and seek out the fall leaves? Those Adirondack Leaf Peepers may not care but if your family is anything like mine, they question everything. So if you are taking kids for a walk or hike why not share a few tidbits about the process.


Just like our bodies are like a factory processing food, a tree's leaves convert its food to provide the nutrition it needs to remain healthy.


What makes leaves green?
Chlorophyll. Leaves are green because of a chemical that allows them to use the sun and oxygen into usable energy or food.


What do trees eat?
Well, sunlight, water and carbon dioxide is converted into glucose (a form of sugar) from the leaves which in turn gives the trees energy.


What is photosynthesis?
It is the process used to convert sun and carbon dioxide to oxygen and glucose. Yes, it's back to science class!


What causes leaves to turn color?

Pigments are produced by leaf cells. Chlorophyll turns leaves to green, carotenoid (yes, like in carrots) turns leaves to yellow, orange or brown and anthocyanins (also found in strawberries and cherries) turn leaves to red. 


Chlorophyll (green) and carotenoids (yellows) are always present in the leaves. The anthocyanins are produced in the falls as a result of light and excess sugar in the leaf cells. 


In the summer the green color overshadows the other colors. Once chlorophyll is no longer being produced, it breaks down revealing the other colors.


Warm days and cool nights will cause the brilliant red colors. The warm days produce more sugar (glucose) in the leaves but the cool nights traps the sugar in the leaves. 


What colors do common trees produce?

  • oaks: red, brown or rust
  • hickories: golden bronze
  • dogwood: purple-red
  • birch: bright yellow
  • paper birch, yellow birch, poplar, aspen: golden yellow
  • sugar maple: orange-red
  • black maple: glowing yellow
  • red maple: bright scarlet

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