Emily Kwong

And Nell, from what I understand, you have been getting really into autumn leaves lately.

Well, some of them, some of them, particularly the red ones.

Red freckles, that's so cute.

Okay, today on the show, the mystery of red leaves.

What are scientists' best ideas about what a tree might get from going ginger?

Okay, Nell, so you and I have talked about how in autumn the level of green chlorophyll goes down and the amount of red pigment goes up, at least in some trees.

Right.

Not all go red.

What do scientists think is going on?

Don't they eat it for breakfast?

What exactly is being protected, though?

Because beautiful as these leaves are, aren't they just going to fall off and die anyway?

It's like a last ditch.

We're going to help the tree out as it transitions.

Fascinating.

OK, are there studies and experiments that support this idea?

three tree species that are normally red, but these ones were yellow.

Like the nitrogen didn't get into the tree itself.

It was shed without the red pigment.

Fascinating.