It’s spring, and if you’ve take a stroll around your neighborhood, you might see early buds on the trees, and flowers poking through the soil. Sofia Rudin takes us on a walk with Providence College professor Maia Bailey.



Sofia Rudin: Can you describe where we're walking now?

Maia Bailey: We're walking up the main drive on PC's campus. We have some beautiful crimson maples and we also have a few cherry trees. And you can see the buds on these cherry trees are getting nice and fat. And starting to get a little bit of color to them.

S: They're so tiny. I mean, walking past, I might not even notice them.

M: Right, exactly.

S: So how do trees know when to make their flowers?

M: [Laughs] Trees have several different ways of sensing what's going on in the world. So not only does temperature affect them, but they can also keep track of day-length. They have a very special chemical called a phytochrome that has two different conformations. And it will switch back between those two different forms depending on if it's getting visible light or not. And so by letting that reaction go overnight, it can tell how long it's been dark out.

S: So just so to make sure I'm understanding right, they're sort of using a combination of the daylight and the temperature?

M: Right. They don't even turn on those suits genes to be like, hey I'm making flowers now, until they know it's the right time of year. Because flowers need to cross pollinate with other flowers. And so they need to have some coordinated time where they're each flowering so that their animal friends can show up and move pollen in between them.

And so, that's why people are getting concerned about climate change. As we keep getting more and more extreme, we're worried that we might not get fruits certain years because pollinators aren't there to make that happen.

S: And talk to me a bit about what scientists are finding with climate change, how it's affecting the flowering.

M: There's a huge effect of each year's kind of average temperature. But because that average temperature is changing with climate change, that the first day of flowering is steadily moving earlier and earlier in the spring.

You can see that we've got a bunch of little buds of daffodils coming up here. But further along these nice green shoots are of hellebore. That's gonna be a hellebore flower.

S: Well thank you so much for the tour!

M: Yeah! Yes, no problem.