The Slice from PBS North.

Hello, I'm Jessica Savage.

I'm an associate professor at the University of Minnesota, and I'm here to talk about why leaves change color.

Leaves turn colors because the tree is recycling nutrients.

It puts a lot of nutrients into the leaves during the year.

And before they drop, it pulls them back.

And there's a lot of resources, especially nitrogen in the pigment that makes leaves green, which is chlorophyl.

that's retrieved by the plant.

And because that's pulled out we see other colors emerge.

Temperature plays a big role in leaf color change.

If we have a really warm summer and autumn, it can delay.

When the colors turn, it can also impact how bright they are.

So we get brighter colors when we have cooler days and especially cooler nights.

If we're in a drought, there's a chance that we'll have dimmed colors or we'll have earlier leaf drop, especially in some more drought sensitive trees.

Right around Lake Superior, we have a really steep gradient in terms of the climate.

If you go by the lakeside at this time of year, it's very different than when you go inland.

And because of that, we can see a big range in the timing of when color change her happens.

I love going up to Hawk Ridge, Rock Knob in Hartley.

I think sometimes the most brilliant displays just are really small.

Down on the Lake walk, There's a whole bunch of creeper on the walls that always turns bright red, right below the rose garden.

That's really beautiful.

The slice from PBS North.