Way out on Park Point -- past the Aerial Lift Bridge, past the Bay Side Market, past the city beach -- there's an airport.
A handful of planes are anchored near a few metal hangars. They're two-seaters and four-seaters, some on wheels and some on floats. Past the airport stands a grove of pines, thriving somehow on the narrow strip of sand between Lake Superior and the St. Louis River bay.
As the sun sets, the city lights twinkle through the pines.
Louise Levy and some friends stuff their mittened hands in pockets and look around.
"There's a different feel when you're here," Levy says. "This is a special place."
Levy is a volunteer on the Duluth Tree Commission. She's also a forester.
"There's red and white pine, so it's a mixed pine stand. And in fact there's a lot of natural white pine regeneration," she points out. "On the ground there's a lot of pine needles and red and white pine cones. And then, if you follow your eye up the trees, a lot of the branches have fallen off because it's so dark."
This patch of wilderness in the city is so rare, the DNR has designated it as a Scientific and Natural Area. That offers it special protections for preservation.
But here's the problem. The trees are too close to the runway, and so the airport doesn't meet federal and state safety rules. In December, the Duluth Airport Authority announced it would have to cut some trees.
Some locals have been battling the Sky Harbor Airport almost since the day it was built, back in the late 1940s. Jan Olson is part of that fight. She says a lot of people thought things were resolved a few years ago when the airport cut some trees and installed a fence.
"If we top a tree or cut some trees today and put up a light, in five more years we'll have more trees that we'll have to cut, because now they're also in the way of the airplanes," she says. "There's no sense that it will ever stop."
Olson says the trees were here first, and the airport should move the runway away from the trees. There's not enough room for that now. But every year the harbor is dredged, and some local folks say the soil that's dredged could be deposited here to build up the land.
The airport has a small but steady customer base. Jon Messerer maintains and repairs the little airplanes that use the airport. Sky Harbor is one of only four airports in the state where pilots can conveniently switch from floats to wheels.
"I've got customers from Minneapolis, central Wisconsin, northern Wisconsin, northern Minnesota," he says. "They come from all over to have floats taken off and put on. And then you get a lot of traffic from people heading north to Canada, and returning from Canada to get fuel, clear Customs."
That's right, this little airport is a U.S. Customs station.
Right now, the Duluth Airport Authority issues a "notice to airmen" warning that trees present an obstacle in the approach to the runway. Pilots can get the notice on a web page they can check before they fly.
But the Federal Aviation Authority and MnDOT say that's not enough. Airport Authority director Brian Ryks says they've told him to take care of the obstacles.
"And they have a couple of levers they hold over our heads," says Ryks. "One is funding: 'if you don't get your approach area taken care of, you won't be eligible for future state and federal funding for maintaining the airport and making improvements.'"
At first, Ryks thought just a few trees would have to be cut, and he got permission last summer from the DNR's Scientific and Natural Areas program to take about seven old-growth trees.
Once the crews started measuring, though, they realized a lot more would have to go, perhaps a hundred.
No one wants to cut that many trees.
Ryks says he's going to start over. He's going to call together all the agencies and concerned citizens, and try to find a solution.