Transcripts

CATHY WURZER: It's about 7:20 on a Thursday morning. I'm glad you're with us. I'm Cathy Wurzer with Minnesota Public Radio News. Expert fire crews from Montana are expected to begin work today on Minnesota's Pagami Creek Wildfire, a fire that continues to burn in the Boundary Waters Canoe Area Wilderness.

Ahead of the fire, some homes have been evacuated, and folks hope the weather will help tamp down the blaze. It's the biggest fire in the Boundary Waters in more than a century. But historically, big forest fires used to be commonplace in that area. In fact, they're part of a natural process that rejuvenates the ecosystem.

Lee Frelich is a forest ecologist at the University of Minnesota. He joins us this morning on the phone. Good morning, Professor.

LEE FRELICH: Good morning, Cathy.

CATHY WURZER: I'm betting that forest fires offer an interesting lab for researchers like you. What do you find in the aftermath of these fires?

LEE FRELICH: Well, you find that a lot of trees within the fire perimeter are still alive, and they are the seed source for the future forest. You find areas that are black as a moonscape and burned down to bare rock. It's very interesting. And the things that you see pop up in the fire will be having several PhD students at the University of Minnesota looking into the aftermath of these big fires we've had in recent years.

CATHY WURZER: And I want to ask you about that. Cavity Lake and the Ham Lake fires in the BWCA were pretty much back to back. Now there's this Pagami Creek Fire. What does the frequency of these big fires say to you?

LEE FRELICH: Well, it looks like the frequency of big fires is increasing in the last decade. But if you look back historically, for the last 300 years, during the 1600s, 1700s, 1800s, a fire as big as the Pagami Creek Fire occurred about once a decade on average. And then during the 1900s, there were hardly any fires of significant size after 1910 in the Boundary Waters. And now we seem to be returning to a period with big fires again. So I think the anomaly was the 1900s when we had fewer fires.

CATHY WURZER: What about maybe the climate nowadays? Does that factor into why we may be seeing more warm, dry weather?

LEE FRELICH: I think it is, with a much warmer climate that we're experiencing in Northern Minnesota today. This new pattern of more extreme droughts and floods will be conducive to fires because you get those long gaps without rainfall. And that's more characteristic of the climate that you see out on the Great Plains than a forest climate which tends to have more even rainfall. So it may be an indication that as we've been predicting, the climate of the savannas and prairies to the west is beginning to shift into Minnesota.

CATHY WURZER: Generally speaking though, is a fire like the Pagami Creek Fire ecologically beneficial to the forest?

LEE FRELICH: Yes. These fires are necessary because the species of trees that grow in the Boundary Waters are fire-dependent. Jack pine and black spruce, for example, have closed cones that don't open unless there is a fire. And even the birch and aspen resprout from their roots. They're killed on top by the fire, but often their roots survive, and then they sprout after the fire.

And in fact, in the absence of fire. Spruce, fir, and cedar tend to take over, and you get more of a homogeneous landscape. When you have these fires occurring in different places across the landscape, then you get a mosaic of forest in different stages of succession, and there are species of wildlife that use all different stages.

Moose, for example, would probably benefit from having a lot of younger forests. We think that these recent fires will have a lot of young birch saplings in them, and that's one of the favorite foods of the moose. So having a mixture of different forest ages on the landscape is something that will happen if fires occur on a regular basis over time.

CATHY WURZER: Always a pleasure talking to you, Professor.

LEE FRELICH: Well, it was a pleasure talking to you. Thank you for having me on.