From the brains behind brains on, this is the moment of um.

Um, um, um, um, um, um, um, um, moment of um comes to you from APM studios. I'm Rosie DuPont.

Um.

When I look out my window, I can see that spring has officially sprung.

The birds are singing, the flowers are blooming, and all the best climbing trees are sprouting new leaves.

Now that winter is over, I like to change up my style a little bit.

I put away my heavy coats and sweaters, take out my t-shirts, and I even start wearing brighter colors,

vibrant pinks and greens and oranges and blues. Of course, humans aren't the only ones who change

how we dress with the seasons. Right now, trees are budding with green, but last fall, it was like a tree

fashion show. Most of the leaves have turned a mix of vivid reds and bright

oranges, golden yellows, and rich purples. That inspired Summer to ask this great question about the

reason behind trees' seasonal outfit changes. Hi, my name is Summer from San Carlos, California. My question is, why do leaves change color only in the fall?

That is a great question. So I'm Marley-Steugood. I work at the Yale School of the Environment, where I teach classes in forest ecology and tree identification, which we call dendrology.

I'm also a licensed forester, a horticulturist,

and a plant ecologist, so all the things that have to do with loving plants for the most part.

I would start by saying that leaves don't only change color in the fall. We can actually sometimes

get some changes of colors on leaves of certain types of plants at other times in the year. And example, a lot of leaves will get a little bit of red on the edges when they first come out

in the spring, or they might be a little purple early in the season, or if a plant's really stressed

during the year, you might see in the middle of summer a maple tree that puts on red leaves

where everything else is still green. And so it's not only the

fall, but at least here in the northeast, we're really known for our autumn foliage. And we get the

majority of the vibrant color in the fall. And the reason that we get so much color change in the

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