Written By Karl VonBerg.

Posted on April 1st, 2020.

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Did you think red leaves were just a fall color? So did I, until I noticed some leaves are red in spring and summer.

Did you think red leaves were just a fall color? So did I, until I noticed some leaves are red in spring and summer. 

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This picture is of a Red Maple taken June 6!

OK maybe not the brilliant red of fall, but still red. So what is up with that? What makes them red? How long do they stay red? Why are they red? Hold on, one question at a time.

Let’s start with some more obvious things. Like, where do you notice the red leaves? Are they the newest, smallest, younger growth? Or on the older leaves? Or on all leaves? Check out these pictures and see what you find.

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Red Maple

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Dogwood

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Red Oak

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Hophornbeam

I see the red on the newer, younger, smaller leaves.

Now we can start making some sense of what is going on:

  • The red color we see in the spring is made up of pigments called anthocyanins.
    • These pigments come from an abundance of sugar that moves into the new leaves to give them energy to grow.
    • The sugar gets converted into the red pigments or anthocyanins.
  • As the leaf grows and uses anthocyanins, they become less plentiful. So the red color is reduced.
  • As the new leaf is exposed to sunlight more green-colored chlorophyll is produced. This green color replaces the red color.
  • If there is a cooler, cloudier spring then the leaves stay red for longer due to the slower production of the green chlorophyll.

Scientists who study how trees function have suggested that anthocyanins may help the new leaves in several ways:

  • To withstand frost
  • To keep ultraviolet rays from damaging the leaf
  • To help protect the leaf from air pollution

So now you can impress your friends about red leaves in spring!

Better yet, how about taking a walk with them in an area that has smaller trees scattered around (your own back yard or a local park)? See if you can spot some red leaves and enjoy their splash of color in the new green landscape of spring.


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